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A list of forthcoming papers related to immunology is presented. These include "Variable influences of iodine on the T-cell recognition of a single thyroglobulin epitope," by Hong Jiang, "Triacylated lipoproteins derived from Mycoplasma pneumoniae activate NF-jB through TLR1 and TLR2," by Takashi Shimizu, and "Disruption of Rxra gene in thymocytes and T lymphocytes modestly alters lymphocyte frequencies, proliferation, survival and Th1/Th2 balance," by Alexander Borowsky and Kevin Kent Lloyd.

Pulmonary fibrosis involves various types of immune cells and soluble mediators, including TGF‐β and IL‐35, a recently identified heterodimeric cytokine that belongs to the IL‐12 cytokine family. However, the effect of regulatory IL‐35 may play an important role in fibrotic diseases. The aim of this paper is to explore the immunoregulatory role of IL‐35 in the development of fibrosis in interstitial lung disease (ILD). To gain a better understanding of this issue, the concentrations of IL‐35 and different profibrotic cytokines in fibrotic (F‐ILD) and non‐fibrotic (NF‐ILD) patients by ELISA were compared to that of intracellular IL‐35 and IL‐17 on CD4+ T cells stimulated in the presence of BAL or with different ratios of recombinant IL‐35 (rIL‐35) and TGF‐β (rTGF‐β), which were evaluated by flow cytometry. We observed that BAL concentration of IL‐35 was lower in F patients (p < 0.001) and was negatively correlated with concentrations of TGF‐β (p < 0.001) and IL‐17 (p < 0.001). In supplemented cell cultures, BAL from NF but not F patients enhanced the percentage of IL‐35 + CD4+ T (p < 0.001) cells and decreased the percentage of IL‐17 + CD4+ T cells (p < 0.001). The percentage of IL‐35 + CD4+ T cells correlated positively with BAL concentration of IL‐35 (p = 0.02), but correlated negatively with BAL concentrations of IL‐17 (p = 0.007) and TGF‐β (p = 0.01). After adjusting the concentrations of recombinant cytokines to establish a TGF‐β: IL‐35 ratio of 1:4, an enhanced percentage of IL‐35 + CD4+ T cells (p < 0.001) but a decreased percentage of IL‐17 + CD4+ T cells (p < 0.001) was observed. After adding recombinant IL‐35 to the BAL from F patients until a 1:4 ratio of TGF‐β: IL‐35 was reached, a significantly increased percentage of IL‐35 + CD4+ T cells (p < 0.001) and a decreased percentage of IL‐17 + CD4+ T cells (p = 0.003) was found. These results suggest that IL‐35 may induce an anti‐fibrotic response, regulating the effect of TGF‐β and the inflammatory response on CD4+ T cells. In addition, the TGF‐β: IL‐35 ratio in BAL has been shown to be a potential biomarker to predict the outcome of F patients with ILD. [ABSTRACT FROM AUTHOR]

New short-lived strains of mice (SAM-P), which have been developed by Takeda et al. (1981), show a defective antibody response to T dependent (TD) antigen in vitro, as demonstrated in the accompanying paper (see page 419). In the present study, we investigated the cellular site of the defect, using a cell culture system. In this paper, it is demonstrated that T-helper (Th) cell activity for the antibody response to TD antigen is impaired, while other cellular immune responses, e.g. mixed leucocyte reaction, cytotoxic T-lymphocyte response, and delayed-type hypersensitivity reaction, are normal. These results suggest that the defect in T-helper subset is limited in helper function for the antibody response, and that the helper function for the cell-mediated immune responses is intact. These two functions of the T-helper subset are apparently regulated in a different manner. The SAM-P strains of mice may thus serve as an appropriate model for studying functional heterogeneity in T-helper/inducer cell subsets. [ABSTRACT FROM AUTHOR]

As the amount of biomedical information available in the literature continues to increase, databases that aggregate this information continue to grow in importance and scope. The population of databases can occur either through fully automated text mining approaches or through manual curation by human subject experts. We here report our experiences in populating the National Institute of Allergy and Infectious Diseases sponsored Immune Epitope Database and Analysis Resource ( IEDB, http://iedb.org), which was created in 2003, and as of 2012 captures the epitope information from approximately 99% of all papers published to date that describe immune epitopes (with the exception of cancer and HIV data). This was achieved using a hybrid model based on automated document categorization and extensive human expert involvement. This task required automated scanning of over 22 million PubMed abstracts followed by classification and curation of over 13 000 references, including over 7000 infectious disease-related manuscripts, over 1000 allergy-related manuscripts, roughly 4000 related to autoimmunity, and 1000 transplant/alloantigen-related manuscripts. The IEDB curation involves an unprecedented level of detail, capturing for each paper the actual experiments performed for each different epitope structure. Key to enabling this process was the extensive use of ontologies to ensure rigorous and consistent data representation as well as interoperability with other bioinformatics resources, including the Protein Data Bank, Chemical Entities of Biological Interest, and the NIAID Bioinformatics Resource Centers. A growing fraction of the IEDB data derives from direct submissions by research groups engaged in epitope discovery, and is being facilitated by the implementation of novel data submission tools. The present explosion of information contained in biological databases demands effective query and display capabilities to optimize the user experience. Accordingly, the development of original ways to query the database, on the basis of ontologically driven hierarchical trees, and display of epitope data in aggregate in a biologically intuitive yet rigorous fashion is now at the forefront of the IEDB efforts. We also highlight advances made in the realm of epitope analysis and predictive tools available in the IEDB. [ABSTRACT FROM AUTHOR]

The first paper in this series reported that it was possible to reconstitute the response of low concentrations of mouse spleen lymphocytes to concanavalin A (Con A) by adding small numbers of peritoneal exudate cells (PEC) to the cultures. In this paper it is shown that the role of the PEC in this system can be partially replaced by conditioned medium (CM) prepared from PEC cultures or completely replaced by CM taken from lymphocytes cultured at optimal concentration. These CM were inactive unless fresh Con A was added to the assay cultures. Activity was present in CM which was incubated with lymphocytes or PEC for the shortest possible time but maximal activity was found after 24 hr of incubation. Activity was also found in CM prepared in the absence of Con A. Only in the case of lymphocytes cultured at optimal concentration for 24 hr was there substantially more activity in the CM thus prepared if Con A was present. PEC preparations depleted of T lymphocytes produced as much activity in CM as the untreated control. CM produced by PEC was less sensitive to heat treatment or to freezing and thawing than that produced by lymphocyte cultures. [ABSTRACT FROM AUTHOR]

In the early 1970s a spate of papers by research groups around the world provided evidence for a negative regulatory role of thymus-derived lymphocytes (T cells). In 1971, Gershon and Kondo published a seminal paper in Immunology entitled ‘Infectious Immunological Tolerance’ 1 indicating that such negative regulation could be a dominant effect that prevented otherwise ‘helpful’ T cells from mediating their function. Over the next decade, suppressor T cells, as these negative regulatory cells became known, were intensively investigated and a complex set of interacting cells and soluble factors were described as mediators in this process of immune regulation. In the early 1980s, however, biochemical and molecular experiments raised questions about the interpretation of the earlier studies, and within a few years, the term ‘suppressor T cell’ had all but disappeared from prominence and research on this phenomenon was held in poor esteem. While this was happening, new studies appeared suggesting that a subset of T cells played a critical role in preventing autoimmunity. These T cells, eventually dubbed ‘regulatory T cells’, have become a major focus of modern cellular immunological investigation, with a predominance that perhaps eclipses even that seen in the earlier period of suppressor T cell ascendancy. This brief review summarizes the rise and fall of ‘suppressorology’ and the possibility that Tregs are a modern rediscovery of suppressor T cells made convincing by more robust models for their study and better reagents for their identification and analysis. [ABSTRACT FROM AUTHOR]

MHC class I-related gene protein (MR1) is a non-polymorphic MHC class IB antigen-presenting molecule that is the restricting molecule for mucosal-associated invariant T (MAIT) cells, a prominent population of innate-like antibacterial T cells. The MAIT cell-MR1 axis represents a new paradigm in antigen presentation, with the MR1 ligand derived from vitamin B compounds or their metabolic precursors. Many bacteria and some fungi produce the activating ligand for MR1. In evolution, MR1 is highly conserved in most, but not all, mammals. In humans and rodents it is expressed in a broad range of cell types, both haematopoietic and non-haematopoietic, although cell surface expression has been difficult to detect. Although MR1 trafficking shares features with both the MHC class I and MHC class II pathways, it is distinct. Several strands of evidence suggest that the intracellular location where MR1 is loaded differs for soluble ligand and for ligand derived from intact bacteria. The regulation of MR1 surface expression may also vary between different cell types. This paper will review what is currently known about the expression and trafficking of MR1 and propose a model for the loading and trafficking of MR1. [ABSTRACT FROM AUTHOR]

Summary: There have been substantial strides forward in our understanding of the contribution of regulatory T (Treg) cells to cancer immunosuppression. In this issue, we present a series of papers highlighting emerging themes on this topic relevant not only to our understanding of the fundamental biology of tumour immunosuppression but also to the design of new immunotherapeutic approaches. The substantially shared biology of CD4+ conventional T (Tconv) and Treg cells necessitates a detailed understanding of the potentially opposing functional consequences that immunotherapies will have on Treg and Tconv cells, a prominent example being the potential for Treg‐mediated hyperprogressive disease following anti‐PD‐1 therapy. Such understanding will aid patient stratification and the rational design of combination therapies. It is also becoming clear, however, that Treg cells within tumours exhibit distinct biological features to both Tconv cells and Treg cells in other tissues. These distinct features provide the opportunity for development of targeted immunotherapies with greater efficacy and reduced potential for inducing systemic toxicity. [ABSTRACT FROM AUTHOR]

As described in an accompanying paper, trinitrophenyl (TNP) modification of pork insulin (PI) at the A1 glycine position allows this molecule to stimulate a proliferative response in H-2b (B10) mice. We now show that this antigen stimulates low IgG responses in the same strain of mice. Our results show that T-cell help and proliferation may therefore be regulated independently. [ABSTRACT FROM AUTHOR]

It is known that two major cytotoxins, lymphotoxin (LT) and tumour necrosis factor (TNF), are produced by T cells and macrophages, respectively. We report in this paper that a human T-cell hybridoma, AC5-8, produces TNF in addition to LT depending on the kind of stimuli used. When phorbol myristate acetate (PMA) and concanavalin A (Con A) or PMA alone were used to induce AC 5-8 cells to secrete a cytotoxin, we found that the cytotoxin secreted was antigenically indistinguishable from LT. On the other hand, when AC5-8 cells were activated by PMA and A23 187, they secreted another cytotoxin which was antigenically indistinguishable from TNF, in addition to LT. These two cytotoxins could be separated by affinity chromatography on a column of Con A-Sepharose. A cytotoxin, which did not bind to the Con A-Sepharose column and showed about 70- 95% of the total cytotoxic activity secreted from AC5-8 cells stimulated with PMA and A23 187, was found to be antigenically identical to TNK. The other cytotoxin, which bound to the Con A-Sepharose column and showed only 5 - 30% of the total activity induced by PMA and A23 187, was found to be antigenically identical to LT. [ABSTRACT FROM AUTHOR]

MRL-lpr mice and their congenic counterparts MRL- + spontaneously develop an autoimmune disease that resembles systemic lupus erythematosus in humans. The two strains, although congenic, differ by a considerable number of disease parameters, reflecting the expression of the lpr autosomal recessive gene. One paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigated a possible lpr gene-encoded macrophage defect in these mice. It was found, however, that both the MRL- + and MRL-lpr mice failed to divide in response to Con A, the lack of division correlating with an inability to secrete the growth promoter interleukin-2. In MRL- + mice and young MRL-lpr mice this non-responsiveness was corrected by the addition of normal CRA PEC. The defect could not be explained by a failure of M RL- + or M RL-lpr peritoneal exudate cells to quantitatively or qualitatively provide a source of interleukin-1 to Con A-activated T cells or by the possibility that the peritoneal exudate cells were blocked in their function by the presence of sera-derived autoantibodies and/or immune complexes on their membranes. We postulate that the inability of T cells to proliferate in MRL congenic mice can be explained by two defects: (i) the failure of antigen-presenting cells in MRL- + and MRL-lpr to provide the necessary signals to immunocompetent T cells, this defect not being associated with the lpr gene, and (ii) the lpr gene controlled outgrowth of a unique T-cell population that cannot respond in our assay system. [ABSTRACT FROM AUTHOR]

T-colony formation can be induced in PHA-stimulated peripheral blood mononuclear cells (PBM) from man, but not in PHA-stimulated purified T cells, the latter requiring the presence of factors produced by PHA-stimulated PBM and termed T-colony promoting activity (TCPA). In this paper, we demonstrate that interleukin-2 (IL-2), the growth hormone of T lymphocytes, controls T-colony formation. We show that: (i) IL-2 activity and TCPA produced by PHA-activated PBM are co-purified by gel filtration and chromatography on blue agarose, a procedure which yields a 850-fold IL-2 purification; (ii) recombinant IL-2, produced by genetically manipulated Eseherichia coli, can induce T-colony formation in PHA-stimulated purified T cells; (iii) Monoclonal antibody against the IL-2 receptor (anti-Tac antibody) completely inhibits the T-colony formation in PHA-stimulated PBM when directly added to the culture system. [ABSTRACT FROM AUTHOR]

In the previous paper we showed that the immune response to sheep red cells (SRBC) was degenerate; serum antibodies showed increasing loss of specificity, signalled by cross-reactions with horse RBC (HRBC), with time after immunization and with hyperimmunization. In the present report we have analysed the role T cells may play in this process. To do this we studied the antibodies made by mice deprived of T cells by irradiation as well as those made by normal mice immunized with SRBC in distilled water, which was shown to depress the DNA synthetic response of T cells. In both instances the mice with fewer responding T cells made less antibody which could agglutinate HRBC than did the appropriate controls. This was true even when no difference in anti-SRBC titre was apparent. In addition we showed that the antibody made by mice with reduced numbers of T cells was less effective at passive suppression of the immune response to SRBC than was similarly titred (against SRBC) antibody made by normal mice. Thus, certain sub-populations of antibodies, normally made in response to SRBC, immunization, are particularly thymus dependent. We have discussed why we think they are those of particularly high affinity. [ABSTRACT FROM AUTHOR]

In a companion article to this study,1 the successful programming of a JAWSII dendritic cell ( DC) line's antigen uptake and processing was demonstrated based on pre-treatment of DCs with a specific 'cocktail' of select chemokines. Chemokine pre-treatment modulated cytokine production before and after DC maturation [by lipopolysaccharide (LPS)]. After DC maturation, it induced an antigen uptake and processing capacity at levels 36% and 82% higher than in immature DCs, respectively. Such programming proffers a potential new approach to enhance vaccine efficiency. Unfortunately, simply enhancing antigen uptake does not guarantee the desired activation and proliferation of lymphocytes, e.g. CD4+ T cells. In this study, phenotype changes and antigen presentation capacity of chemokine pre-treated murine bone marrow-derived DCs were examined in long-term co-culture with antigen-specific CD4+ T cells to quantify how chemokine pre-treatment may impact the adaptive immune response. When a model antigen, ovalbumin ( OVA), was added after intentional LPS maturation of chemokine-treated DCs, OVA-biased CD4+ T-cell proliferation was initiated from ~ 100% more undivided naive T cells as compared to DCs treated only with LPS. Secretion of the cytokines interferon-γ, interleukin-1β, interleukin-2 and interleukin-10 in the CD4+ T cell : DC co-culture (with or without chemokine pre-treatment) were essentially the same. Chemokine programming of DCs with a 7 : 3 ratio of CCL3 : CCL19 followed by LPS treatment maintained partial immature phenotypes of DCs, as indicated by surface marker ( CD80 and CD86) expression over time. Results here and in our companion paper suggest that chemokine programming of DCs may provide a novel immunotherapy strategy to obviate the natural endocytosis limit of DC antigen uptake, thus potentially increasing DC-based vaccine efficiency. [ABSTRACT FROM AUTHOR]

Natural killer ( NK) cells provide an immediate first line of defence against viral infections. Memory responses, maintained by CD4+ T cells, require exposure to viral antigen and provide long-term protection against future infections. It is known that NK cells can promote the development of the adaptive response through cytokine production and cross-talk with antigen-presenting cells. In this paper however, we summarize a series of recent publications, in mouse models and for the first time in man, with the unifying message that rapid viral antigen control by the innate immune system limits antigen exposure to CD4+ cells thereby abrogating the development of a memory response. We discuss the significant implication of these studies on viral treatment strategies and immunization models. [ABSTRACT FROM AUTHOR]

Discusses the 'Immunology' paper by Smith et al. and its contribution to understanding at which point in the immune response to antigen the critical decision making between an active versus a tolerogenic response may take place. Induction of oral tolerance initially to provoke the activation of T cells; Possible role of the antigen-presenting cells present in the intestine in determining the T-cell response to antigen.

SummaryAn immunodominant epitope of human immunodeficiency virus-1 (HIV-1) gp160 recognized by Dd class I major histocompatibility complex (MHC) molecule-restricted, CD8+ cytotoxic T lymphocytes (CTL) was originally identified as a peptide composed of 15 amino acids (P18IIIB: RIQRGPGRAFVTIGK). However, further study has indicated that a 10-mer peptide, I-10 (RGPGRAFVTI), within P18IIIB is the minimal-sized epitope and the trimming step(s) of two carboxyl terminal amino acids (GK) is essential to produce I-10 from P18IIIB. In the processing, angiotensin-1-converting enzyme (ACE), found in sera, plays a central role in generating I-10. Target cells could be sensitized with I-10 under conditions where ACE activity in the sera was abrogated. In contrast, in the case of P18IIIB, requiring further processing to delete the C-terminus of two amino acids in order to act, sensitization of target cells was completely abrogated under the conditions. Pretreatment of target cells with brefeldin A (BFA), preventing the presentation of endogenous antigens from the class I MHC molecule pathway, did not inhibit the presentation of P18IIIB. Moreover, glutaraldehyde-fixed cells, which can not process native protein, though they could present the exogenously added peptides, were also sensitized by P18IIIB. These results clearly demonstrate that the fine processing to produce I-10 occurred in the extracellular milieu. Furthermore, our result suggests that the longer P18IIIB can bind to the class I molecules on the cell surface, and then be trimmed by ACE while it is bound. The mechanisms behind the extracellular processing outlined in this paper will offer important information for designing peptide-based vaccines to elicit MHC molecule-restricted effectors. [ABSTRACT FROM AUTHOR]

Chronic rhinosinusitis (CRS) represents chronic inflammation of the sinus mucosa characterised by dysfunction of the sinuses' natural defence mechanisms and induction of different inflammatory pathways ranging from a Th1 to a Th2 predominant polarisation. Recalcitrant CRS is associated with Staphylococcus aureus dominant mucosal biofilms; however, S. aureus colonisation of the sinonasal mucosa has also been observed in healthy individuals challenging the significance of S. aureus in CRS pathogenesis. We aimed to investigate the relationship between CRS key inflammatory markers, S. aureus biofilm properties/virulence genes and the severity of the disease. Tissue samples were collected during endoscopic sinus surgery from the ethmoid sinuses of CRS patients with (CRSwNP) and without (CRSsNP) nasal polyps and controls (n = 59). CD3+ T‐cell subset frequencies and key inflammatory markers of CD4+ helper T cells were determined using FACS analysis. Sinonasal S. aureus clinical isolates were isolated (n = 26), sequenced and grown into biofilm in vitro, followed by determining their properties, including metabolic activity, biomass, colony‐forming units and exoprotein production. Disease severity was assessed using Lund–Mackay radiologic scores, Lund–Kennedy endoscopic scores and SNOT22 quality of life scores. Our results showed that S. aureus biofilm properties and CRS severity scores correlated positively with total CD4+ T‐cell frequencies but looking into CD4+ T‐cell subsets showed an inverse correlation with Th1 and Th17 cell frequencies. CD4+ T‐cell frequencies were higher in patients harbouring lukF.PV‐positive S. aureus while its regulatory and Th17 cell subset frequencies were lower in patients carrying sea− and sarT/U‐positive S. aureus. Recalcitrant CRS is characterised by increased S. aureus biofilm properties in relation to increased total CD4+ helper T‐cell frequencies and reduced frequencies of its Th1, Th17 and regulatory T‐cell subsets. These findings offer insights into the pathophysiology of CRS and could lead to the development of more targeted therapies. [ABSTRACT FROM AUTHOR]

Vaccines based on tumour‐specific antigens are a promising approach for immunotherapy. However, the clinical efficacy of tumour‐specific antigens is still challenging. Twelve conjugates with self‐assembly properties were designed and synthesized using MAGE‐A1 peptide and TLR2 agonist, combined with different covalent bonds. All the developed conjugates formed spherical nanoparticles with a diameter of approximately 150 nm, and enhanced the efficacy of the peptide vaccines with the better targeting of lymph nodes. All the conjugates could well bind to serum albumin and improve the plasma stability of the individual antigenic peptides. In particular, conjugate 6 (N‐Ac PamCS‐M‐6) had a more significant ability to promote dendritic cell maturation, CD8+ T cell activation, and subsequent killing of tumour cells, with an in vivo tumour inhibition rate of 70 ± 2.9%. The interaction between specific response and the different conjugation modes was further explored, thereby providing a fundamental basis for novel immune anti‐tumour molecular platforms. [ABSTRACT FROM AUTHOR]

In a previous report, we investigated inflammatory responses induced by injecting Listeria monocytogenes into one testis of a mouse. We demonstrated that the contralateral testis also developed an orchitis despite the absence of bacteria, indicating that the inflammation on the uninfected, contralateral side was of autoimmune character. In both infected and autoimmune testes, γδ and αβ T cells infiltrated during the inflammation. In this paper, we present the data of a comparison of the character of γδ T cells of the infected and autoimmune testes. In both testes, γδ T cells appeared to be activated, as assessed by high CD44 and low l-selectin expression. Analysis of T-cell receptor (TCR) usage in both inflammation types revealed the same γδ TCR repertoire. Finally, the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated that γδ T cells in both types of inflammation were capable of producing interleukin-2 (IL-2), IL-4, interferon-γ (IFN-γ), IL-10 and transforming growth factor-β (TGF-β). These results imply that γδ T cells present in infected-induced and autoimmunity-induced inflammation have the same characteristics and could work as immunoregulatory cells. [ABSTRACT FROM AUTHOR]

We have previously reported that T lymphocytes proliferating in vitro to the hapten trinitrochlorobenzene (TNCB) exhibit a very restricted Vβ gene usage and response to TNCB is limited to T-cell receptors (TCR) composed of Vβ8.2 in combination with Vα3.2, Vα8 and Vα10. This paper investigates the role played by T lymphocytes expressing the Vβ8.2 gene segment in the contact sensitivity (CS) reaction to TNCB in the intact mouse and in its passive transfer into naive recipient mice. Mice injected with monoclonal antibodies to Vβ8 are unable to develop CS upon immunization with TNCB and 4-day TNCB-immune lymph node cells from mice that had been depleted in vivo or in vitro of Vβ8+ T lymphocytes fail to transfer CS. However, when separated Vβ8+ and Vβ8- cells were used for passive transfer, it was found that Vβ8+ T lymphocytes failed to transfer CS when given alone to recipient mice and a Vβ8- population was absolutely required. Further analysis revealed that within the Vβ8- population, T lymphocytes expressing the γδ TCR were fundamental to allow transfer of the CS reaction. These γδ cells were found to be antigen non-specific, genetically unrestricted and to rearrange the Vγ3 gene segment. This indicates that transfer of the CS reaction requires cross-talk between Vβ8+ and γδ+ T lymphocytes, thus confirming our previous results obtained using TNCB-specific T-cell lines. Time–course experiments showed that Vβ8+ lymphocytes taken 4–24 days after immunization with TNCB were able to proliferate and produce interleukin-2 (IL-2) in response to the specific antigen in vitro. Similar time–course experiments were then undertaken using the passive transfer of the CS reaction system. The results obtained confirm that TNCB-specific... [ABSTRACT FROM AUTHOR]

In our recent studies, an inhibitor of vacuolar-type H+-ATPase, concanamycin A (CMA) has been shown to neutralize acidic pH in vacuolar organelles, including lytic granules, and to decrease the perforin content markedly. In the present paper, we have further investigated the role of acidification in perforin storage by using CMA. In CD8+ cytotoxic T-lymphocyte (CTL) clones, the amount of perforin decreased rapidly at 30–90 min but no more decrease occurred at 90–120m in after the addition of CMA. Since exposure to actmomycin D, cyclohexlmide, or brefeldin A failed to reduce the perforin content, the perforin decrease in CMA-treated cells seems to be largely due to a reduction in the perforin already stored in lytic granules, rather than to the inhibition of the de novo synthesis or the intracellular glycoprotein transport of perforin. Diisopropylfluorophosphoridate (DFP) markedly antagonized the decrease in the perforin content in CMA-treated cells, while other protease inhibitors, i.e. antipain, E-64, leupeptin, pepstatin A and phenylmethylsulphonyl fluoride, did not. Nevertheless, DFP hardly reversed the abrogation of the killing activity by CMA. Indeed, the lytic granules prepared from DFP plus CMA-treated cells showed only a marginal level of haemolytic activity. In cell-free experiments using perforin-enriched granule fractions, acidic pH completely blocked the perforin activity. Under the acidic conditions, perforin was more resistant to an inactivation by calcium when exposed to calcium prior to the haemolysis test. Thus, these data suggest that perforin is primarily inactivated, possibly in a calcium-dependent manner, and is subsequently hydrolysed by DFP-sensitive proteases in the lyric granules at neutral pH. We conclude that acidic pH plays an essential role to maintain the integrity of perforin within the lyric granules. [ABSTRACT FROM AUTHOR]

Heat-shock proteins (hsp) represent a highly conserved family of proteins, normally localized in the cytoplasm and nucleus, whose expression is induced in situations involving cell stress. This paper reports the unusual translocation of hsp to the cell membrane of T cells undergoing apoptosis. We observed that glucocorticosteroid-induced thymocyte death is associated to the surface expression of hsp 60 and hsp 70 in a discrete fraction of apoptotic cells, hsp surface expression is closely related to a thymic subset of immature CD3low/- T cells. The expression of surface hsp 60 appears early after treatment with dexamethasone (3 hr) whereas the membrane expression of hsp 70 follows different kinetics and peaks later. Morphological analysis of the hsp+ apoptotic cells suggest that this subset represents late-stage apoptotic cells at their minimal volume before fragmentation into apoptotic bodies, Membrane expression of hsp is also associated with apoptosis in peripheral blood mononuclear cells from AIDS patients cultured in vitro. Altogether, we show that a discrete fraction of cells undergoing apoptosis expresses membrane hsp 60 and hsp 70, supporting the hypothesis that apoptosis causes a radical alteration in the expression of cell surface molecules. Surface hsp expressed during apoptosis may constitute a novel immune-context able to generate packages of self- and exogenous antigens, originating from degradation of altered cells. [ABSTRACT FROM AUTHOR]

Lymphocyte migration into inflammatory sites involves a change from a spherical, non-motile phenotype to an irregular, constantly shape-changing, motile phenotype. We have previously shown that lymphocytes are maintained in the non-motile state by the constitutive activity of protein kinase C (PKC). In this paper we have attempted to identify the PKC isotype which regulates these morphological changes by three different approaches. (a) Motile and non-motile T- cell lines were compared for expression of the α, βI, βII, γ, δ, ε, η, ζ and θ isotypes by Western blotting. There was no obvious correlation of isotype expression with motility. (b) Two different PKC inhibitors, one specific for classical isotypes, Go6976 and the other GF109203X, which inhibits both classical and non-classical isotypes were compared for induction of motility in non- motile lymphocytes. Only GF109203X induced motility implying that a non-classical isotype is involved. (c) Non-motile lymphocytes were chronically treated with the PKC activator bryostatin and the time courses of induction of motility and downregulation of PKC isotypes were compared. Induction of motility correlated better with downregulation of ε, η and θ than with α or β. It is concluded that the data fit best with the involvement of a non-classical PKC isotype in regulating lymphocyte motility although no association with a particular isotype was found. [ABSTRACT FROM AUTHOR]

It is now well documented that the mode of primary stimulation in the mouse determines the ratio of Th1-, Th0- or Th2-type T cells obtained. In this paper we determine whether driving and cloning human peripheral blood mononuclear cells (PBMC) non-specifically with interleukin-2 (IL-2) and/ or IL-4 and mitogen, will differentially select T cells for IL-10 production. The presence of IL-2 during culture (with or without IL-4) yielded predominantly Th1-type clones (81% of clones with IL-2 alone and 77% with IL-2 + IL-4) and a low frequency of Th0-type clones (19% of clones with IL-2 and 10% of clones with IL-2 + IL-4), whereas IL-4 alone increased the yield of the IL-4 producing Th0 (35%) clones. The proportions of IL-2-producing clones did not alter with treatment; however, the combination of IL-2 + IL-4 altered the proportions of IL-10-producing clones. 47% of IL-2-cultured cells and 51% of IL-4-cultured cells produced IL-10 respectively, whereas only 22% of clones driven with IL-2 + IL-4 produced detectable levels of IL-10. Thus in the preliminary experiments described here we have demonstrated that the cytokines used to initially drive out human T cells and maintain the T-cell growth can skew the Th1/Th2/Th0 cytokine profiles of the clones obtained from mitogen-stimulated cultures. Moreover and unexpectedly the proportion of IL-10-producing cells is altered. These results are important in interpreting analysis of the cytokine profiles of human T cells and raise questions concerning how we should derive T-cell clones for a cytokine analysis that truly reflects the in vivo situation. [ABSTRACT FROM AUTHOR]

Peripheral lung tissue contains large numbers of T cells, strategically located for immune surveillance at the blood-air interface. Given the intensity of antigenic exposure at this site, it is clear that local T-cell activation events require strict control, in order to maintain tissue homeostasis. How this control is achieved in this unique tissue microenvironment is unknown, and the present study sought to elucidate the process via detailed analysis of the surface phenotypic characteristics of freshly isolated lung T cells. We report below that these cells display typical characteristic of ‘postactivation’, notably elevated basal Ca2+ concentrations, down-modulated T-cell receptors, expression of Ia and ‘late’ activation antigens and concomitant CD4/CD8. However, levels of interleukin-2 receptor and CD2 expression were below those expected of ‘activated’ T-cell populations, and virtually all of the cells were found to be in the G0/G1 phases of the cell cycle. These properties bear a remarkable similarity to those of T cells activated in the presence of endogenous tissue (alveolar) macrophages from the lung (see accompanying paper). We hypothesize that they reflect the in vivo operation of an endogenous macrophage-mediated T-cell anergy-induction process, the function of which is to limit the local clonal expansion of T cells in peripheral lung tissue after in situ activation. [ABSTRACT FROM AUTHOR]

Alveolar macrophages (AM) are recognized as archetypal ‘activated’ macrophages with respect to their capacity to suppress T-cell responses to antigen or mitogen, and this function has been ascribed an important role in the maintenance of local immunological homeostasis at the delicate blood: air interface. The present study demonstrates that this suppression involves a unique form of T-cell anergy, in which ‘AM-suppressed’ T cells proceed normally through virtually all phases of the activation sequence including Ca2+ flux, T-cell receptor (TCR) modulation, cytokine [including interleukin-2 (IL-2)] secretion and IL-2 receptor (IL-2R) expression. However, the ‘suppressed’ T cells fail to up-regulate CD2, and do not re-express normal levels of TCR-associated molecules after initial down-modulation; moreover, they are unable to transduce IL-2 signals leading to phosphorylation of IL-2R-associated proteins, and remained locked in G0/G1. The induction of this form of anergy is blocked by an NO-synthase inhibitor, and is reversible upon removal of AM from the T cells, which then proliferate in the absence of further stimulation. We hypothesize that this mechanism provides the means to limit the magnitude of local immune responses in this fragile tissue microenvironment, while preserving the capacity for generation of immunological memory against locally encountered antigens via clonal expansion of activated T cells after their subsequent migration to regional lymphoid organs. In an accompanying paper, we demonstrate that a significant proportion of T cells freshly isolated from lung exhibit a comparable surface phenotype. [ABSTRACT FROM AUTHOR]

Previously we have identified an immunodominant, eight-residue, epitope core sequence (TAAGNVNI) from the 19 000 MW protein of Mycobacterium tuberculosis, which is recognized in the context of multiple H-2 I-A molecules. In this study, the role of residues flanking this T-cell epitope core was examined, using a series of 20 mer analogue peptides in which the native flanking residues were progressively replaced with L-alanine. Analogue peptides were tested for their capacity to stimulate a CD4+ 19000 MW protein-specific T-cell line, revealing that all but one N-terminal flanking residue could be replaced collectively by alanine without significant loss of stimulatory activity. However, clear H-2-associated differences in the requirement for flanking residues were demonstrated with peptide-specific T-cell hybridomas. In particular, H-2d-derived hybridomas were much more stringent in their requirement for flanking residues than were hybridomas. All polyalanine-substituted peptides bound I-Ab molecules, with affinities similar to the native unsubstituted peptide. In contrast, significantly reduced binding to I-Ad was observed with several analogue peptides, although without a clear relationship to the degree of substitution. Furthermore, in H-2b mice, neither immunogenicity nor cross-reactivity with the native peptide showed a clear inverse relationship with respect to the degree of alanine substitution. The results presented in this paper indicate that flanking residues can influence T-cell specificity and that these effects may be controlled by major histocompatibility complex (MHC) haplotype. [ABSTRACT FROM AUTHOR]

A receptor which binds secretory lgA (sIgA) is expressed on human T cells from patients with systemic lupus erythematosus, rheumatoid arthritis, Behcet's syndrome and IgA nephropathy and on normal T cells following phytohaemagglutinin (PHA) stimulation. The specificity of this receptor was initially probed with a panel of normal serum immunoglobulins in competitive inhibition assays with sIgA using two-colour immunofluorescence. While the receptor showed the strongest affinity for igAl (IC5010-6 M), IgD which has a similarly glycosylated hinge region to IgAl, also bound to the receptor (IC50 10-5 M). IgA2, which lacks the 'O'-glycosylated hinge region, did not significantly inhibit the binding at these concentrations suggesting that the IgA determinants for this receptor might be the oligosaccharides present in the hinge region of IgAl. IgAl has up to 10 'O'-linked oligosaccharides and four N-linked oligosaccharides per molecule. In order to probe the role of the 'O'-linked hinge sugars in the binding event, a sugar library was prepared from IgAl by a procedure designed to release 'O'-linked oligosaccharides preferentially, and to retain them in the natural closed ring formation. The sugars were released by hydrazinolysis at 65° and the resulting oligosaccharide library analysed by high voltage paper electrophoresis (HVE) and P4 gel permeation chromatography. Competitive inhibition studies demonstrated that both the library and the individual 'O'-linked sugars associated with IgA1 were implicated in the binding of IgAl to this receptor (IC50 between 1 × 10-5 M and 6 × 10-s M). Within this range the individual sugars showed small differences in their affinity for the receptor in the following order: Galβ3GalNAc = NeuNAc2α3(6)Galβ3GalNAc > NeuNAc2α3(6)Galβ3[NeuNAc2α6]GalNAc ≥ GalNAc. [ABSTRACT FROM AUTHOR]

This paper investigates the Vβ usage of lymph node cells from mice immunized with TNP and of cell lines made from them. In cell lines stimulated weekly with TNP in vitro for 1 month, about 87% of the cells were Vβ8+ and further analysis showed that these cells were actually Vβ.2+. This was also true for the cells that proliferated in lymph nodes in response to TNP 4 days after primary immunization, i.e. proliferation occurred mainly in the Vβ+, and in particular in the Vβ8.2+, population while much less proliferation occurred when the Vβ8- or Vβ8.2- T-cell populations are used. This was not due to non-specific damage during separation, as the response to concanavalin A and alloantigen was intact. In a separate series of experiments, mice were acutely depleted of Vβ8+ T cells by treatment with F23.1 or a control monoclonal antibody (mAb) in vivo given before immunization. Treatment with the relevant mAb virtually abolished the response to TNP. In contrast, SJL mice, which lack the gone segment coding for the Vβ8 family and several other Vβ chains, made a normal proliferative and delayed-type hypersensitivity (DTH) response to TNP. This poses the problem, which may he important in the study of the T-cell repertoire, of why acute removal of Vβ8+ T cells, which are dominantly used in the response to TNP, does not allow T cells using other chains to substitute in the response, while the absence of this population over a long period of time, because of a deletion in the genome, allows the use of T cells hearing other Vβ chains. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to study the γδ T-cell receptor repertoire and target specificity following stimulation of peripheral T cells of BALB/c mice with autologous or bacterial ligands. The expression of Vγ and Vδ chain families in T cells that had been expanded by stimulation in syngeneic mixed lymphocyte culture or with purified protein derivative (PPD) was determined by the semiquantitative DNA polymerase chain reaction (PCR) method. Responder T cells to either of these stimuli strongly expressed both Vδ5 and Vδ6 genes. However, addition of the ML 30 anti-murine heat shock protein (hsp) 60 monoclonal antibody (mAb) to the cell culture selectively inhibited only the expansion of Vδ5 T cells. A Vδ5 T-cell hybridoma (KMT-5), which recognized syngeneic splenic and fibrosarcoma Meth A cells but not allogeneic cells, was produced by cell fusion from autoreactive blast cells. Incubation of the KMT-5 hybridoma in the presence of ML 30 antibody blocked the stimulation of interleukin-2 (IL-2) secretion by syngeneic target cells. It was also found that the DNA of KMT-5 hybridoma and of the autoreactive γδ T cells contained the BALB/c invariant delta (BID) chain sequence. It is concluded from these results that BALB/c peripheral Vδ5 T cells recognize an autologous hsp 60 target specificity in a Vδgene restricted manner. We also propose that T cells of this V gene family may be involved in the immune surveillance of certain tumours and intracellular infections. [ABSTRACT FROM AUTHOR]

CD27 is a T-cell surface antigen expressed on the majority of peripheral T cells and belongs to a newly defined receptor family including the iow-affinity nerve growth factor receptor, tumour necrosis factor (TNF) receptors, the B-cell activation antigen CD40, and the Fas antigen. Although the function of CD27 has not been defined, several experimental observations support the notion that this molecule plays an important role in the process of T-cell activation. In this paper, we have demonstrated that a rapid hyperphosphorylation of CD27 is induced by a cyclic AMP-inducing agent, forskolin, and a membrane-permeable cAMP analogue, 8-bromo-cAMP, as well as phorbol 12-myristate 13-acetate (PMA). In addition, increased phosphorylation of CD27 in T-cell activation either via CD2 or CD3 pathways was strongly suppressed by a cyclic nucleotide-dependent kinase inhibitor, H-8, but only slightly by a protein kinase C inhibitor, staurosporine. These results suggest that protein kinase A might be a key kinase responsible for CD27 phosphorytation in the process of T-cell activation. CD27 is the first T-cell surface antigen demonstrated to be phosphorylated by the cyclic AMP-protein kinase A-mediated pathway. [ABSTRACT FROM AUTHOR]

The non-obese diabetic (NOD) mouse is a model for the study of insulin-dependent diabetes mellitus (IDDM). Recently transgenic NOD mice have been derived (NOD-E) that express the major histocompatibility complex (MHC) class III-E molecule. NOD-E do not become diabetic and show negligible pancreatic insulins. The possibility pertained that NOD-E mice are protected from disease by a process of T-cell deletion or anergy. This paper describes our attempts to discover whether this was so, by comparing NOD and NOD-E mouse T-cell receptor Vβ usage. Splenocytes and lymph node cells were therefore tested for their ability to proliferate iii response to monoclonal anti-Vβ antibodies. We were unable to show any consistent differences between NOD and NOD-E responses to the panel of antibodies used. Previously proposed Vβ were shown to be unlikely candidates for deletion or anergy. T cells present at low frequency (Vβ5+) in both NOD and NOD-E mice were shown to be as capable of expansion in response to antigenic stimulation as were more frequently expressed Vβ. Our data therefore do not support deletion or anergy as mechanisms which could account for the observed disease protection in NOD-E mice. [ABSTRACT FROM AUTHOR]

This paper describes a T-cell targeting strategy based on the use of an antigen-monoclonal antibody heteroconjugate. A rat anti-idiotypic monoclonal antibody specific for a murine B-cell lymphoma was conjugated to the purified protein derivative (PPD) of tuberculin. This construct selectively delivered up to 4.5 &times 104 molecules of PPD onto each tumour cell. Targeted PPD was internalized for endosomal processing and was presented in association with the I-A class II restriction element to PPD-reactive T-helper (Th) cells. Activated Th cells were demonstrated to proliferate and secrete significant levels of tumour necrosis factor (TNF). Such lymphokine secretion was observed at a PPD concentration as low as 1 ng/mI. Despite the secretion of TNF, the S-cell lymphoma was found to be resistant to autonomous Th-mediated cytotoxicity. Targeted Th cells did, however, activate tumourcidal macrophages that subsequently mediated significant tumour cytostasis. Based on this observation, it is proposed that the targeting system described may be exploited as the basis for a future immunotherapeutic strategy. [ABSTRACT FROM AUTHOR]

This paper examines helper T-cell responses and antibody titres and isotypes following immunization with a peptide antigen in association with three different adjuvants. B10.A mice were primed with pigeon cytochrome c fragment 81-104 in association with the adjuvants complete Freund's adjuvant (CFA), incomplete Freund's adjuvant (IFA) and alum. Strong antibody responses, dominated by IgG1, were observed upon priming with CFA and IFA. In contrast, priming with alum induced a weak antibody response with little or no detectable antigen-specific IgG1. These differences did not correlate with differences in T-cell priming, as immunization with peptide in association with all three adjuvants induced comparable T-cell proliferative responses and frequencies of antigen-specific cells. In addition, no significant differences in iiiterleukin-2 (IL-2), interferon-gamma (IFN-γ) and IL-4 production could be found, suggesting that the adjuvants did not differentially affect Th1 and Th2 cells. [ABSTRACT FROM AUTHOR]

Lectins can be used to detect changes in cell-surface glycosylation. In this paper we examine the lectin-binding characteristics of murine T cells as measured by flow cytometry. A large panel of labelled lectins was used to stain naive, activated and resting murine T cells. Some lectins did not detectably bind any T cells, some bound to all T cells and some bound to only a subset of splenic T cells. Three lectins which preferentially bind to previously activated T cells were identified: Bandeiraea simplicifolia BS-I, Bauhinia purpurea and Lycopersicon esculentum. In addition, two lectins were found to bind preferentially to activated T cells; Glycine max and Triticum vulgaris. Finally, no differences were found in the ability of a large panel of lectins to bind to Th1 and Th2 clones. Lectin binding may be a powerful tool for distinguishing naive, activated and memory T cells. [ABSTRACT FROM AUTHOR]

This paper describes a model of successful immunotherapy of advanced lymphoma based on the selective elimination of cycling tumour-induced suppressor T cells. It shows that a single injection of the anti-mitotic drug, vinblasting (Vb), results in complete regression of a large L5178Y lymphoma and its metastases, but not if it is growing in an immunocompetent host. Vb-induced, immunologically mediated tumour regression was dependent on the anti-tumour function of CD8+ T cells, because regression was prevented by depleting the host of this subset of T cells 24 hr after Vb was given. Regression was also prevented by infusing the host with Vb-sensitive, CD4+ T cells from a turnout-bearing donor. These and other results are in keeping with the interpretation that Vbinduced regression of the L5178Y lymphoma depends on the ability of the drug to eliminate CD4+ suppressor T ceils that are replicating, and to spare non-replicating CD8+ effector cells, it is suggested that at an advanced stage of growth of the L5178Y lymphoma the host possesses an acquired population of antigen-primed CD8+ effector T cells that are unable to become activated in response to abundant tumour antigen because of the dominant influence of CD4+ suppressor cells. Activation of these CD8+ T cells was indicated by the finding that they were rapidly converted from being cyclophosphamide (Cy) resistant to being highly Cy sensitive within 48 hr of giving Vb. [ABSTRACT FROM AUTHOR]

Evidence from in vitro studies indicates that immunoglobulin A (IgA) responses are highly T dependent, yet investigations of the requirement for cognate help For IgA responses in tiro have not previously been undertaken. Experiments reported in this paper employ hapten-carrier immunization of individual Peyer's patches (PP), the site of generation of IgA antibody-containing cells (ACC) responding to lumenal antigenic challenge in the intestine, to determine the requirements for T-cell and B-cell priming under normal physiological conditions in vivo. These experiments demonstrate that both hapten-specific B-cell priming and carrier-specific T-cell priming in PP are required for an IgA-specific anti-hapten ACC response in the intestinal lamina propria to subsequent lumenal challenge with hapten-carrier conjugate. These results confirm that IgA B-cell induction in PP requires cognate T-cell help. An IgA ACC response can also be obtained when hapten and carrier priming occur in different PP, providing functional significance for our previous observations that PP-derived T-helper cells are able to migrate between PP after priming. [ABSTRACT FROM AUTHOR]

The leucocyte common antigen, CD45 (T200, Ly-5), exists in a number of isoforms generated by differential usage of three exons that code for an extracellular region close to the NH2 terminus. Use of antibodies to different isoforms of CD45 has lead to the identification of two subsets of CD4+ T cells in rat, man and mouse. Data on the functions of the two rat CD4+ T-cell subsets isolated on the basis of different levels of expression of exon B (and/or C) are largely concordant with those obtained from the two subsets of human CD4 + T cells defined by their levels of expression of exon A. However, results presented in this paper on the CD45 phenotype of rat T cells that produce interferon-gamma (IFN-γ) are not compatible with the human data, if it is assumed that there are only two functional subsets of CD4+ T cells. The data could, in principle, be reconciled if the expression of exons A and B defined three rather than two subsets, and this possibility has now been examined in man where monoclonal antibodies against both A and B exon products are available. The results show the presence of a third CD4+ T-cell subset and that this extra subset is contained within the population originally shown to provide memory T-cell function. [ABSTRACT FROM AUTHOR]

The experiments described in this paper have examined the migration of three fluorochrome-labelled T-lymphocyte subsets (CD4+, CD8+ and γδ+T19+) on a single passage from blood to lymph, through prescapular lymph nodes. Lymphocytes obtained from prescapular efferent lymph were labelled in vitro with fluorochrome and returned to the blood of the same animal. Over the next 2 days, lymph was continuously monitored and the cells in all collections, including the one used for intravenous infusion, were phenotyped and analysed by flow cytometry. Significant differences in the subset ratios between the infused, starting population and the recirculated population iodicated that CD4+ and γδ+T19+ lymphocytes are extracted by a resting lymph node at the same rate and that both are extracted at a faster rate than CD8+ lymphocytes. The results presented here also suggest that a unique subset of γδ+T19+ lymphocytes may be present in blood that does not recirculate through peripheral lymph nodes. [ABSTRACT FROM AUTHOR]

In a previous paper we described how the toxin ricin stimulates IgE but not IgG antibody responses in rats. In this study we have examined the cellular basis for this observation. The proportion of CD4- and CD8-positive cells present in the spleen at the peak of the IgE response was determined. Those animals injected with both ricin and antigen produced a substantial IgE response (50-fold increase). Their CD4+/CD8+ ratio was also markedly increased (P> 0.001l)compared with animals given toxin or antigen alone. In addition, mitogen-stimulated proliferation of mononuclear cells from spleens of the IgE-producing rats was enhanced nearly five-fold compared with cells from animals given toxin or allergen alone. The sensitivity of CD4- and CD8-positive rat spleen cells from unexposed animals to ricin in vitro was also studied. Spleen cells from untreated rats were co-cultured with optimal doses of mitogen and varying amounts of ricin. Mitogen-driven proliferation was inhibited at l0-3-10-6 mg/ml ricin. This effect was abrogated by the addition of as little as 0.01 m lactose but not by as much as 10 mg/mI mannan to the culture. Cultures depleted of CD4+ cells by rosetting were approximately 100 times more sensitive to ricin (P>0.01). Furthermore, the proportion of CD8 + to CD4+ cells present after culture of untreated cells with mitogen and ricin was significantly reduced. These results show (i) that the ability of ricin to increase the IgE response depends on the administration of antigen together with the toxin; (ii) that CD8+ spleen cells are more sensitive to ricin than CD4 + cells; (iii) that increased IgE responsiveness is associated with a reduction in the proportion of CD8- relative to CD4-positive cells in the spleen and increased responsiveness to mitogen. We believe that enhancement of the IgE responses by ricin may be due to inactivation of IgE-specific T-suppressor cells generated by immunization with antigen and speculate that these may be some or all of those bearing the CD8 marker. [ABSTRACT FROM AUTHOR]

There is no doubt that HLA-DR molecules are acting as the products of HLA-linked immune response genes (Ir-genes), because (i) HLA-DR molecules are the restriction elements in the interaction between CD4+ helper T cells and antigen-presenting cells (APC) to respond to many antigens such as streptococcal cell wall antigen (SCW) (Nishimura & Sasazuki, 1983; Sone et al., 1985; Hizayama et al., 1986), schistosomal antigen (Sj) (Hirayama et al., 1987), Mycobacterium leprae antigen (ML) (Kikuchi et al., 1986) and so on; and (ii) anti-HLA-DR monoclonal antibodies completely abolish the immune response to those antigens (Nishimura & Sasazuki, 1983; Sone et al., 1985). However, genetic analysis of the immune response to those antigens in families or populations revealed that responsiveness is recessive and non-responsiveness to those antigens is a dominant genetic trait that is tightly linked to HLA (Sasazuki et al., 1980a, 1983; Watanabe et al., 1988). This is completely opposite to the situation under the Ir-gene control where responsiveness is dominant and non-responsiveness is recessive. In this paper, we report evidence of how we came across the concept of HLA-linked immune suppression genes (Is-genes) besides Ir-genes, and show evidence for the epistatic interaction between HLA-DR and DQ to determine the immune response to several antigens in humans. [ABSTRACT FROM AUTHOR]

As perhaps the staunchest advocates of repertoire purging as the central mechanism of immunological tolerance, we note with satisfaction a spate of recent, elegant papers which suggest an intrathymic clonal abortion model as the explanation for at least some examples of T-cell tolerance. This view agrees with the classical formulation of the Billingham-Brent-Medawar school of tolerance as a specific, central failure of immune responsiveness. Repertoire purging within the B-lymphocyte compartment remains much more controversial. There is no doubt that experimental models exist where the B cell is the reversible target of tolerance induction. The question is, in view of the ease of inducing autoantibody formation both in vivo and in vitro, just how relevant are such clonal anergy mechanisms to authentic self-tolerance? Arguments are presented that there must be two windows of tolerance susceptibility in the ontogeny of the B cell; one while it is maturing in the bone marrow, to prevent autoreactivity of high affinity to important accessible self-antigens; and a second soon after activation of pre-memory cells by exogenous antigen, to prevent fortuitous mutations towards high-affinity anti-self-reactivity establishing a forbidden clone. [ABSTRACT FROM AUTHOR]

We previously reported that incubation of human peripheral blood mononuclear cells (PBMC) for 5 days with T-cell growth factor (ICGF) resulted in lymphokine-activated killer activity against endothelial cells (EC). In this paper we report on the effects of short-term incubation of PBMC with lymphokines. We show that incubation of PBMC with lymphokines during an 18-hr period is sufficient to generate a strong cytolytic response against EC. The cytolytic capacity of the effector cells was directly dependent on the dose of lymphokine added during the induction phase. When PBMC were separated into adherent and non-adherent cells, the non-adherent fraction could be induced to lytic activity against EC, whereas the adherent cells could not. When PBMC were separated, using 2-amino-ethylisothiouronium bromide hydrobromide-treated sheep red blood cells (AET-SRBC), into T- and non-T-cell fractions, the latter fraction could be induced to lyse EC. TCGF-induced cell-mediated EC lysis could not be inhibited using anti-T3 nor antie-LFA-l antibodies. Lysis of EC by TCGF-stimulated effector cells was strongly inhibited by the addition of unlabelled K562 target cells, whereas cold OKT3 hybridoma cells did not exert such an effect. In conclusion: the kinetics of the induction of lytic activity against EC, as well as the cell separation experiments, suggest that short-term-activated NK cells may lyse EC. This hypothesis was confirmed using monoclonal antibody and cold target cell analysis. [ABSTRACT FROM AUTHOR]

The thoracic duct or efferent prescapular duct was cannulated in four fetal calves aged 121-259 days post-conception. The duration of lymph flow ranged from 2 to 20 days and the mean flow rates sustained over these collection periods varied from 54 to 488 ml/hr. Lymphocyte output ranged from 44 × 106 cells/hr in thoracic duct lymph from a 121-day fetus to 3.9 × 108 cells/hr in efferent prescapular lymph from a 259-day fetus. The circulating lymphocyte pool in fetal calves of about 120 and 190 days gestational age was calculated to contain, respectively, 4 × 108 cells and 2 × 1010 cells. The proportion of lymphocytes bearing surface immunoglobulin detected in fetal lymph ranged from 2.1% to 8.7%. Recirculating lymphocytes from fetal calves produced strong proliferative responses when stimulated by T-cell mitogens but responded poorly to B-cell mitogens. Fetal lymphocytes also responded to stimulation by allogeneic cells and stimulated other cells to proliferate during mixed lymphocyte culture. When stimulated with Con A, fetal lymphocytes secreted IL-2 to a degree that was indistinguishable from the secretory behaviour of lymphocytes from adult animals. The results presented in this paper show that chronic lymphatic fistulae can be established successfully in fetal calves to give access to recirculating lymphocytes. This provides a new experimental approach for studying the development of the bovine immune system. [ABSTRACT FROM AUTHOR]

A panel of monoclonal antibodies (mAb) was developed by the fusion of Sp2/0 myeloma cells and spleen cells from mice immunized with peripheral blood mononuclear cells (PMNC) or T cells from NIH swine leucocyte antigen (SLA) inbred miniature swine. Twenty stable hybridoma clones were isolated that secreted mAb that reacted with swine PMNC, as determined by an enzyme-linked immunosorbent assay (ELISA). The binding profile to swine PMNC and the ability to fix complement of these mAb were investigated by flow cytometric analyses. The molecular weights of the antigens recognized by six of the mAb were determined by immunoprecipitation of 125I-surface-labelled PMNC, followed by SDS-PAGE under reducing conditions. The most interesting mAb, 7-34-1 (IgG2a), precipitated a putative MUC class I molecule composed of a 50,000 MW heavy chain and a 12,000 MW light chain (β2m). This is the third SLA class I-reactive monoclonal antibody to be described for swine. Properties of the mAb described in this paper, mAb 7-34-1, are different from the two other SLA class I-specific mAb that have been described elsewhere in the literature (mAb 74-11-10 and mAb FF85). M onoclonal antibody 7-34-1 recognized class I antigens of SLA haplotypes a, c and din an equivalent manner. This mAb should be especially useful as a general anti- SLA class I reagent for experiments on NIH miniature swine. [ABSTRACT FROM AUTHOR]

In different murine systems, delayed-type hypersensitivity (DTH) swelling responses at 24–48 hr after antigen challenge were preceeded by an early 2-hr swelling response. The 24-hr DTH response is thought to depend on this early (DTH-initiating) hypersensitivity response. In this paper we show that in the syngeneic DBA/2-SL2 routine turnout system only an early 2-hr swelling response can be evoked. This early hypersensitivity response was tumour specific and serotonin dependent. The early hypersensitivity response in contact hypersensitivity has been ascribed to antigen-specific T-cell factors. To test whether similar T-cell factors were involved in the early hypersensitivity response in this syngencic turnout system, we have transferred lymph node, spleen lymphocytes and scram from immunized mice into naive recipients. The serum was fractionated in two fractions, a 50,000–80,000 MW fraction, and a 120,000–190,000 MW fraction. In recipients of lymphocytes, total serum and the 50,000–80,000 MW fraction of the serum, an early hypersensitivity response can be evoked. So, these data suggest the involvement of specific T-cell factors in the development of an early hypersensitivity response against syngeneic tumour cells. Despite the development of an early (DTH initiating) hypersensitivity swelling response these immunized animals cannot develop a classical 24-hr swelling response. This absence of the 24-hr response in the presence of the 2-hr response is discussed in relation to the frequently observed immune suppression in tumour-bearing mice. [ABSTRACT FROM AUTHOR]

MRL-+, MRL-lpr and B6-lpr have been shown to be useful models in studying systemic lupus erythematosus. MRL-lpr and B6-lpr differ from their congenic counterparts by the presence and expression of the homozygous recessive lymphoproliferation (Ipr) gene. One manifestation of this gene is a massive Tall proliferation that results in a generalized lymphadenopathy in older animals. A paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigate the basis for this hypo responsiveness in antigen-induced activation of proliferation and antibody synthesis. We have demonstrated that spleen cells from both MRL-+ and MRL-lpr mice gave minimal stimulation in a one-way mixed lymphocyte reaction against allogeneic T cells. These findings were extended to include antigen-specific proliferation involving antigen that must be processed and presented to responder lymphocytes in a H-2 restricted manner. Thus, MRL- + and MRL-lpr spleen cells pulsed with ferredoxin also failed to stimulate ferredoxin-primed T cells from B10.Br animals in vitro. We then investigated whether any T-cell defect(s) was also contributing to this proliferative hyporesponsiveness. T lymphocytes from the spleen of MRL- +, 2-month-old MRL-lpr, and 6-month-old MRL-lpr were tested in a one-way mixed lymphocyte reaction. It was found that only the MRL- + T cells gave responses approaching normal, suggesting lpr gene involvement in T-cell non-responsiveness. This was confirmed by the demonstration of an age-onset T-cell proliferative hyporesponsiveness in B6. lpr mice. This lpr gene-linked non-responsiveness was also shown to extend to T-cell helper function in a positive allogeneic effect assay. We can conclude from these studies that antigenic non-responsiveness in MRL congenic mice can be explained by two defects: (i) the failure of antigen-presenting cells in MRL- + and MRL-lpr mice to provide the necessary signal(s) to immunocompetent T cells, this defect not being associated with the lpr gene, and (ii) the Ip gene controlled outgrowth of a unique T-cell population that cannot respond in our assay systems. [ABSTRACT FROM AUTHOR]

In the autologous Theileria mixed leucocyte reaction (MLR), irradiated Theileriaparva-infected cells induce proliferative responses in autologous peripheral blood mononuclear leucocytes (PBM)II irrespective of the immune status of the donor animal. In this paper we have analysed the cellular basis of this response in naive and immune cattle to determine the Thelleria specificity of the response. The magnitude of proliferation is dependent on two parameters, namely the presence or absence of monocytes in the responder population, and the phenotype of the parasitized stimulator cells, both of which appeared to be independent of the immune status of the donor animal. Monocyte-depleted responders invariably gave stronger proliferative responses but generated cytotoxicity from immune cattle that tended to be less genetically restricted. Marked differences were observed in the stimulatory capacity of cloned parasitized T-cell and non-T cell lines. At least part of this variation was associated with differences in the capacity of the parasitized cells to secrete soluble suppressive factors and possibly also stimulatory factors. Two observations indicated that, in immune cattle, part of the proliferative response in the autologous Theileria MLR is parasite-specific. First, stimulator cells fixed with glutaraldehyde stimulated proliferative responses in monocyte-depleted PBM from immune animals but not naive animals. Second, in autologous Theileria MLRs with intact PBM, genetically restricted cytotoxic cells were generated from immune but not naive animals. While inonocytes seem not to be required for induction of the parasite-specific component of the response, their absence from the assay when viable stimulator cells are utilized appears to enhance the non- specific component of the proliferative and cytotoxic responses. [ABSTRACT FROM AUTHOR]

Pretreatment of mice by intravenous injection with killed Listeria provided neither delayed-type hypersensitivity to Listeria protoplasm nor protection against Listeria infection. Assuming that this suppression is due to suppressor cells, we attempted to clarify their induction and characterization. Pretreatment with killed BCG instead of killed Listeria suppressed the induction of DTH and protection in subsequent Listeria-immunized mice. Conversely, pretreatment with killed Listeria suppressed subsequent induction of DTH to PPD or protection from tuberculosis. Thus, these suppressions were. induced antigen non- specifically. Transfer of splenic non-adherent cells from killed Listeria-injected mice which had been treated with anti-BAθ serum plus complement, or had been passed through Sephadex G-10 columns, resulted in both afferent and efferent DTH suppression, suggesting that the DTH suppression is closely associated with suppressor T cells. Moreover, the splenic non-adherent cells from killed Listeria-injected mice showed suppression in vitro of listericidal activity of PEC from Listeria-immune mice in the presence of Listeria protoplasm. [ABSTRACT FROM AUTHOR]