Search

Mannose-binding lectin (MBL) exists in the serum as a complex with MBL-associated serine protease (MASP). A recent paper described how MASP-free recombinant rat MBL stimulates the phagocytosis of Escherichia coli and Staphylococcus aureus by rat Kupffer cells through an increase in the level of a phagocytosis receptor. We have examined the effect of human MBL on the phagocytic action of human macrophages. Purified recombinant human MBL stimulated the phagocytosis of E. coli by THP-1 macrophages, leaving that of latex beads, apoptotic human cells, zymosan particles or S. aureus unchanged. This stimulatory effect was observed when either phagocytes or targets were preincubated with MBL. Furthermore, MBL bound to THP-1 macrophages as well as to E. coli, but not to S. aureus, through lipid A. These results indicated that human MBL in the absence of MASP stimulates macrophage phagocytosis of E. coli by bridging targets and phagocytes. [ABSTRACT FROM AUTHOR]

Pemphigus vulgaris (PV) is considered to be an autoimmune disease affecting skin and mucous membranes. Traditionally, PV autoantibodies are thought to recognize antigens located in the intercellular substance (ICS) of keratinocytes; antigens represented mainly by the desmosomal cadherin desmoglein 3 (Dsg3). Accordingly, titres of anti-ICS and anti-Dsg3 immunoglobulin G (IgG) are considered to be major laboratory criteria when making a diagnosis of PV. In this paper, we demonstrated for the first time that PV IgG bind antigen(s) expressed on the surface of peripheral blood mononuclear cells (PBMC), as revealed by immunofluorescence studies. This novel autoantigen is immunoprecipitated by PV IgG as a 130 000 molecular weight protein. However, Western blot analysis of the immunocomplexes failed to show reactivity with anti-Dsg3 monoclonal and polyclonal antibodies. Taken together, our data provide strong evidence that PV autoimmunity targets a 130 000 antigen other than Dsg3 on PBMC. This shifting from epidermis to blood cells may open new perspectives for a better understanding of pemphigus autoimmunity and more rational approaches to its treatment. [ABSTRACT FROM AUTHOR]

CCL25/TECK and CCL28/MEC are CC chemokines primarily expressed in thymic dendritic cells and mucosal epithelial cells. The cognate receptors of CCL25 and CCL28, CCR9 and CCR10, respectively, are mainly expressed on T and B lymphocytes. In human, mouse and pig, CCL25 and CCL28 play a key role in the segregation and the compartmentalization of the mucosal immune system through recruitment of immune cells to specific locations. However, little is known about their role in the ontogeny of the mucosal immune system during fetal development. In the present paper, we report the cloning and the sequencing of ovine CCL25, CCL28, CCR9 and CCR10 and the subsequent assessment of their mRNA expression by q-polymerase chain reaction in several tissues, including thymus, gut-associated lymphoid tissue and mammary gland, from young and adult sheep and in the fetal lamb during the development of the immune system. CCL25 mRNA was highly expressed in thymus and gut while CCL28 mRNA was more expressed in large intestine, trachea, tonsils and mammary gland, especially at the end of gestation. These results are consistent with observations in other species suggesting similar roles for these chemokines in sheep. In fetuses, mRNA of CCL25, CCL28 and their receptors are expressed early in the thymus and mucosal tissues, including the small intestine and the nasal mucosa. Furthermore, their expression increased towards the end of gestation. Consequently, we hypothesize that CCL25 and CCL28 play an important role in the lymphocyte colonization of fetal tissues, enabling the development of a functional immune system. [ABSTRACT FROM AUTHOR]

Summary: The cre‐loxP system has been revolutionary in the field of immunology. The technology enables genetic deletion in mice with unprecedented precision. It is therefore now widely used to investigate gene functions in animal models of disease, and in fundamental studies of the immune response. This widespread adoption of cre‐loxP technology has allowed a thorough investigation of its strengths and weaknesses. Here we highlight an important paper which not only describes potential problems with the commonly‐used screening procedures used when identifying offspring of the correct genotype, but also describes how this screening can be improved to ensure that the right animals are produced. [ABSTRACT FROM AUTHOR]

It has been known for 15 years that the chicken epidermis contains ATPase+ and major histocompatibility complex class II-positive (MHCII+) dendritic cells. These cells were designated as Langerhans cells but neither their detailed phenotype nor their function was further investigated. In the present paper we demonstrate a complete overlapping of ATPase, CD45 and vimentin staining in all dendritic cells of the chicken epidermis. The CD45+ ATPase+ vimentin+ dendritic cells could be divided into three subpopulations: an MHCII+ CD3– KUL01+ and 68.1+ (monocyte-macrophage subpopulation markers) subpopulation, an MHCII– CD3– KUL01– and 68.1– subpopulation and an MHCII– CD3+ KUL01– and 68.1– subpopulation. The first population could be designated as chicken Langerhans cells. The last population represents CD4– CD8– T-cell receptor-αβ– and -γδ– natural killer cells with cytoplasmic CD3 positivity. The epidermal dendritic cells have a low proliferation rate as assessed by bromodeoxyuridine incorporation. Both in vivo and in vitro experiments showed that dendritic cells could be mobilized from the epidermis. Hapten treatment of epidermis resulted in the decrease of the frequency of epidermal dendritic cells and hapten-loaded dendritic cells appeared in the dermis or in in vitro culture of isolated epidermis. Hapten-positive cells were also found in the so-called dermal lymphoid nodules. We suggest that these dermal nodules are responsible for some regional immunological functions similar to the mammalian lymph nodes. [ABSTRACT FROM AUTHOR]

Surfactant protein D (SP-D) is a collectin believed to play an important role in innate immunity. SP-D is characterized by having a collagen-like domain and a carbohydrate recognition domain (CRD), which has a specific Ca2+-dependent specificity for saccharides and thus the ability to bind complex glycoconjugates on micro-organisms. This paper describes the tissue immunolocalization of porcine SP-D (pSP-D) in normal slaughter pigs using a monoclonal antibody raised against purified pSP-D. Porcine SP-D was purified from porcine bronchoalveolar lavage (BAL) by maltose-agarose and immunoglobulin M affinity chromatography. The purified protein appeared on sodium dodecyl sulphate–polyacrylamide gel electrophoresis as a band of∼53 000 MW in the reduced state and∼138 000 MW in the unreduced state. Porcine SP-D was sensitive to collagenase digestion and N-deglycosylation, which reduced the molecular mass to∼24 000 MW and∼48 000 MW respectively, in the reduced state. N-deglycosylation of the collagen-resistant fragment, reduced the molecular mass to∼21 000 MW showing the presence of an N-glycosylation site located in the CRD. Porcine SP-D bound to solid-phase mannan in a dose and Ca2+-dependent manner with a saccharide specificity similar to rat and human SP-D. The purified protein was used for the production of a monoclonal anti-pSP-D antibody. The antibody reacted specifically with pSP-D in the reduced and unreduced state when analysed by Western blotting. Immunohistochemical evaluation of normal porcine tissues showed pSP-D immunoreactivity predominantly in Clara cells and serous cells of the bronchial submucosal glands, and to a lesser extent in alveolar type II cells, epithelial cells of the intestinal glands (crypts of Lieberkühn) in the duodenum, jejunum and ileum and serous cells of the dorsolateral lacrimal gland. [ABSTRACT FROM AUTHOR]

A DNA vaccine based on the heat-shock protein 65 Mycobacterium leprae gene (pHSP65) presented a prophylactic and therapeutic effect in an experimental model of tuberculosis. In this paper, we addressed the question of which protective mechanisms are activated in Mycobacterium tuberculosis-infected mice after immune therapy with pHSP65. We evaluated activation of the cellular immune response in the lungs of infected mice 30 days after infection (initiation of immune therapy) and in those of uninfected mice. After 70 days (end of immune therapy), the immune responses of infected untreated mice, infected pHSP65-treated mice and infected pCDNA3-treated mice were also evaluated. Our results show that the most significant effect of pHSP65 was the stimulation of CD8+ lung cell activation, interferon-γ recovery and reduction of lung injury. There was also partial restoration of the production of tumour necrosis factor-α. Treatment with pcDNA3 vector also induced an immune stimulatory effect. However, only infected pHSP65-treated mice were able to produce significant levels of interferon-γ and to restrict the growth of bacilli. [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.

Summary Secondary lymphoid tissue consists of two major populations of cells: lymphoid cells and stromal cells. It is generally accepted that these two cell populations influence each other however, factors mediating these processes are poorly understood. In this paper we characterize one of the possible means of communication between stroma and lymphocytes namely through hepatocyte growth factor/c-met receptor interactions. Hepatocyte growth factor (HGF) is a pleiotropic factor that is mainly produced by mesenchymal cells and acts on cells of epithelial origin which express the HGF receptor c-met. Here we demonstrate that biologically active HGF is constitutively produced by fibroblast-like stromal cells from human lymphoid tissues. HGF secretion from stromal cells was increased by direct contact with activated T cells. This increase was abrogated when activated T cells were separated physically from stromal cells. Using neutralizing antibody or cytokine inhibitors we provide evidence that enhancement of HGF production was due to additive effects of T-cell membrane-associated interleukin-1 (IL-1) and CD40 ligand. Finally, we also show that B lymphocytes activated with CD40L/anti-µ or phorbol 12-myristate 13-acetate (PMA) express c-met receptor. Co-culture of activated B cells with stromal cells from spleen leads to enhanced production of immunoglobulins. This can be partially inhibited by introduction of anti-HGF neutralizing antibodies to the culture system. Substitution of stromal cells with recombinant HGF did not produce enhancement of immunoglobulin secretion. On the other hand stimulation of c-met receptor with HGF leads to enhanced integrin-mediated adhesion of activated B cells to vascular cell adhesion molecule (VCAM-1) and fibronectin. On the basis of the above experiments we conclude that HGF production by fibroblast-like stromal cells can be modulated by activated T cells, thus providing signals for the regulation of adhesion of c-met expressing B cells to extracellular matrix proteins. In this way HGF may indirectly influence immunoglobulin secretion by B cells. [ABSTRACT FROM AUTHOR]

Summary Tumour necrosis factor-α (TNF-α) is a proinflammatory cytokine produced by several cell types, including T cells upon antigen stimulation. Its production is crucial for the development of an early defence against many pathogens, but its beneficial effects are dependent on the strength and duration of its expression. In this paper we present evidence indicating that serum increases translational efficiency of TNF-α in human peripheral blood mononuclear cells stimulated with superantigen. The increase in translation of TNF-α due to serum could be inhibited by the phosphatidylinositol (PI) 3-K inhibitors, wortmannin and LY294002, suggesting that PI 3-K is involved in the translational control of TNF-α by serum. Similarly to primary T cells, stimulation of Jurkat T cells with superantigen led to TNF-α secretion and this was up-regulated by serum. Transfection of Jurkat cells with a constitutively active form of PI 3-Kα increased the production of TNF-α in cells stimulated with superantigen. Additionally, we used the specific inhibitors targeting ERK kinase and p38 mitogen-activated protein kinase (MAPK), potentially downstream of PI 3-kinase, PD98059 and SB203580. Differently from with PI 3-K inhibitors, the accumulation of TNF-α mRNA was inhibited by PD98059 or SB203580. These results suggest that, in T cells, activation of PI 3-K is an important step in controlling TNF-α protein synthesis in response to growth factors. [ABSTRACT FROM AUTHOR]

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]

Citrullination and homocitrullination are stress induced post‐translational modifications (siPTMs) which can be recognized by T cells. Peripheral blood mononuclear cells isolated from healthy donors and rheumatoid arthritis (RA) patients were stimulated with nine siPTM‐peptides. CD45RA/CD45RO depletion was employed to determine if peptide‐specific responses are naïve or memory. Human leucocyte antigen (HLA)‐DP4 and HLA‐DR4 transgenic mice were immunized with siPTM‐peptides and immune responses were determined with ex vivo ELISpot assays. The majority (24 out of 25) of healthy donors showed CD4 T cell‐specific proliferation to at least 1 siPTM‐peptide, 19 to 2 siPTM‐peptides, 14 to 3 siPTM‐peptides, 9 to 4 siPTM‐peptides, 6 to 5 siPTM‐peptides and 4 to 6 siPTM‐peptides. More donors responded to Vim28‐49cit (68%) and Bip189‐208cit (75%) compared with Vim415‐433cit (33%). In RA patients, the presentation of citrullinated epitopes is associated with HLA‐SE alleles; however, we witnessed responses in healthy donors who did not express the SE allele. The majority of responding T cells were effector memory cells with a Th1/cytotoxic phenotype. Responses to Vim28‐49cit and Eno241‐260cit originated in the memory pool, while the response to Vim415‐433cit was naïve. In the HLA‐DP4 and HLA‐DR4 transgenic models, Vim28cit generated a memory response. Peptide‐specific T cells were capable of Epstein–Barr virus transformed lymphoblastoid cell line recognition suggesting a link with stress due to infection. These results suggest siPTM‐peptides are presented under conditions of cellular stress and inflammation and drive cytotoxic CD4 T cell responses that aid in the removal of stressed cells. The presentation of such siPTM‐peptides is not restricted to HLA‐SE in both humans and animal models. [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]

Keywords: antibodies; mucosal immunology; vaccination; viral EN antibodies mucosal immunology vaccination viral 384 387 4 06/19/23 20230701 NES 230701 Abbreviations 95% CI 95% confidence intervals BAU/mL binding antibody units per mL GMC geometric mean concentrations Vaccination against COVID-19 has mitigated the impact of SARS-CoV-2 infection, decreasing the probability of progression to severe disease and death in vaccinated people. In this study, we observed a high salivary antibody prevalence (81%), detecting antibodies even in children whose last contact with SARS-CoV-2 antigens had been 270 days before sample collection. Antibody concentrations in binding antibody units (BAU) per mL (BAU/mL) were obtained interpolating the OD 450 nm values of samples into a calibration curve constructed with the provided standard (400 BAU/mL). [Extracted from the article]

Summary As is well known in the case of Langerhans cells, dendritic cells (DCs) play a crucial role in the initiation of immunity to simple chemicals such as noted in the contact hypersensitivity. Because DCs are scattered in non‐lymphoid organs as immature cells, they must be activated to initiate primary antigen‐specific immune reactions. Therefore, we hypothesized that some simple chemicals must affect the function of DCs. In this paper, we first demonstrated that human monocyte‐derived DCs responded to such simple chemicals as 2,4‐dinitrochlorobenzene (DNCB), 2,4,6‐trinitrochlorobenzene (TNCB), 2,4‐dinitrofluorobenzene (DNFB), NiCl2 , MnCl2 , CoCl2 , SnCl2 , and CdSO4 by augmenting their expression of CD86 or human leucocyte antigen‐DR (HLA‐DR), down‐regulating c‐Fms expression or increasing their production of tumour necrosis factor‐α (TNF‐α). In addition, the DCs stimulated with the chemicals demonstrated increased allogeneic T‐cell stimulatory function. Next, we found that, among these chemicals, only NiCl2 and CoCl2 induced apoptosis in them. Finally, we examined the effects of these chemicals on CD86 expression by three different macrophage subsets and DCs induced from the cultures of human peripheral blood monocytes in the presence of macrophage colony‐stimulating factor (M‐CSF), M‐CSF + interleukin‐4 (IL‐4), granulocyte–macrophage colony‐stimulating factor (GM‐CSF), and GM‐CSF + IL‐4, respectively. Among them, only DCs dramatically augmented their expression of CD86. These observations have revealed unique characteristics of DCs, which convert chemical stimuli to augmentation of their antigen presenting function, although their responses to different chemicals were not necessarily uniform in the phenotypic... [ABSTRACT FROM AUTHOR]

We previously demonstrated that the majority ( ≥90%) of porcine ileal Peyer's patch (IPP) follicular cells are immature B cells destined to die by apoptosis, when incubated at 37°. In this paper we approached the mechanisms responsible for positive selection of porcine IPP follicular immature B-cell selection, by screening for various cell types, cytokines and polyclonal and monoclonal antibodies for promoting the survival of IPP B cells. Of these reagents, only CD3 cross-linked purified T cells from mesenteric lymph nodes were able to rescue IPP follicular B cells from apoptosis, although polyclonal anti-IPP lymphocyte antibodies delayed apoptosis. This survival effect could be reproduced simply by incubating IPP follicular B cells with soluble and cell membrane-expressed CD 154, an observation consistent with the demonstrated presence of CD40 and CD 154 on porcine IPP follicular B cells and activated T cells, respectively. The IPP follicular B cells rescued in this manner expressed a more mature surface marker phenotype. Immunohistology and fluorescence-activated cell sorter analysis demonstrated that subpopulations of IPP follicular T cells (less than 0.5%) express CD 154. Thus, perhaps unexpectedly, CD 154 on T cells may play a role in the positive selection of immature B cells in the porcine IPP. The origin and control of the activated T cells identified within the porcine IPP remains to be investigated. [ABSTRACT FROM AUTHOR]

Unlike other immunoglobulin G (IgG) subclasses, IgG4 antibodies in plasma have been reported to be functionally monovalent. In this paper we show that the apparent monovalency of circulating IgG4 is caused by asymmetry of plasma IgG4. A large fraction of plasma IgG4 molecules have two different antigen-binding sites, resulting in bispecificity. Sera from patients with IgG4 antibodies to both house dust mite and grass pollen induced cross-linking of Sepharose-bound grass pollen antigen to radiolabelled house dust mite allergen Der p I. This bispecific binding activity was not observed in sera with IgG4 antibodies to either grass pollen or house dust mite exclusively. Depletion of IgG4 antibodies resulted in disappearance of the bispecific activity. By size exclusion chromatography we excluded the possibility that bispecific activity was caused by aggregation of IgG4 antibodies. These results indicate that circulating (polyclonal) IgG4 antibodies have two different antigen-binding sites and therefore are functionally monovalent antibodies. [ABSTRACT FROM AUTHOR]

Fc receptors for immunoglobulin G (IgG) (FcγR) mediate several defence mechanisms in the course of inflammatory and infectious diseases. In Gram-negative infections, cellular wall lipopolysaccharides (LPS) modulate different immune responses. We have recently demonstrated that murine LPS in vivo treatment significantly increases FcγR-dependent clearance of immune complexes (IC). In addition, we and others have reported the induction of adhesion molecules on macrophages and neutrophils by LPS in vivo and by tumour necrosis factor-α (TNF-α) in vitro. The aim of this paper was to investigate CD11b/CD18 participation in LPS enhancing effects on Fcγ-dependent functionality of tissue macrophages. Our results have demonstrated that LPS can enhance antibody-dependent cellular cytotoxicity (ADCC) and IC-triggered cytotoxicity (IC-Ctx), two reactions which involve the Fcγ-receptor but different lytic mechanisms. In vitro incubation of splenocytes from LPS-treated mice with anti-CD11b/CD18 abrogated ADCC and IC-Ctx enhancement, without affecting FcγR expression. Similar results were obtained with physiological concentrations of fibrinogen. In this way cytotoxic values of LPS-splenocytes decreased to the basal levels of control mice. Time and temperature requirements for such inhibition strongly suggested that anti-CD11b/CD18 could modulate intracellular signals leading to downregulation of FcγR functionality. Data presented herein support the hypothesis that functional and/or physical associations between integrins and FcγR could be critical for the modulation of effector functions during an inflammatory response. [ABSTRACT FROM AUTHOR]

Cells of the B-cell lineage play an essential part in the immune response, not only as the producers of antigen-specific antibodies, but also as antigen-presenting cells. Unlike T cells, however, the establishment of long-term normal B-cell lines has proved to be exceedingly difficult. In this paper we demonstrate that cell membrane-expressed CD154 (CD40 ligand) is able to support the continual growth of porcine mesenteric lymph node B-cell cultures for more than 4 months without the addition of exogenous cytokines, such as interleukin-4 (IL-4). Addition of IL-4, but not interferon-γ (IFN-γ) or IL-13, to these cultures enhanced proliferation, as, to a lesser extent, did addition of IL-2. Interestingly, however, whilst IFN-γ-supplemented cultures largely consisted of immunoglobulin M (IgM)-positive cells, cultures with IL-13 or IL-4 contained a significantly increased proportion of IgG-positive cells. [ABSTRACT FROM AUTHOR]

We previously showed that the mixed haplotype Aβz/Aαd major histocompatibility complex (MHC) class II molecules function as restricting element for autoreactive T-cell clones derived from autoimmune prone (NZB×NZW)F1 (B/WF1) mice. Subsequent analysis revealed that some of these Aβz/Aαd-restricted autoreactive T-cell clones were pathogenic upon transfer to pre-autoimmune B/WF1 mice. In this paper, we analysed the peptide-binding motif of Aβz/Aαd class II molecules. Amino acid-sequencing analysis of peptides eluted from purified Aβz/Aαd molecules revealed several sequences, including one that corresponds to murine l-plastin 588–601. Synthetic 18-mer l-plastin 588–605 peptide (SMARKIGARVYALPEDLV, as described by the amino acid single letter code) was demonstrated to bind to Aβz/Aαd MHC class II molecules on transfectant B lymphoma cells (TAβz). A competitive binding inhibition assay using truncation peptides revealed the core sequence for binding resides in 591Arg to 601Pro. Binding inhibition assay using substitution peptides, each having substitution to the other 19 residues at positions from 590Ala to 601Pro, revealed four major anchor sites 592Lys (p1), 594Gly (p3), 595Ala (p4), 597Val (p6) and one minor anchor site 600Leu (p9). Positively charged residues are not allowed at p3 and negatively charged residues are not allowed at p4 and p6. Relatively large hydrophobic residues (Leu, Ile) are not tolerated at p3 and p4. Met and Trp are not tolerated at p6. Based on these findings, the characteristics of peptides recognized by autoreactive T cells in B/WF1 mice are discussed. [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]

The article presents a list of authors who contributed research papers to the April 1, 1996 issue of the journal "Immunology." Some of them are S.E. Adams; E.J. Alfrey; D.W. Alling; C.L. Baldwin; H.C. Bankl; J. Barkans; G. Cambridge; C. Canning; J.L. Ceuppens; K.F. Chung; J.S. Cole; A.D. Crockard; P.J. Daffern; D.C. Dafoe; R.J. Dearman. K. Eshioma, H. Suzuki, S. Yamazaki and N. Shinohara discusses a research paper on derivation of T-cell receptor α-chain double expresser lines from normal murine mature T-cells.

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]

The experiments reported in this paper examine the cell-surface phenotype (CD5, CD4, CD8, TI9, MHC class II and sIg) and cell output of lymphocyte subsets circulating through a subcutaneous lymph node in the sheep fetus, in an environment unaffected by foreign antigen and circulating immunoglobulins. CD4+ lymphocytes were the major T-cell subset in fetal lymph and were clearly enriched in lymph compared with blood, whereas TI9+, CD8+ and B lymphocytes were not. It seems likely that in the fetus CD4+ lymphocytes are extracted from the blood at a faster rate than are other T-cell subsets and B cells. There was a much higher percentage of CD8+ and T null cells and a lower percentage of MHC class II+ and B cells circulating in the fetal lymph than in adult lymph, while the percentage of TI9+ lymphocytes in fetal blood was twice that in the adult. Although the hourly cell output from an adult prescapular lymph node was far higher than that from a fetal lymph node, the circulation of lymphocytes through fetal lymph nodes was much greater per gram lymph node weight than that through adult lymph nodes. The wholesale recirculation in the fetus of all the major T-cell subsets found in the adult is paradoxical because it is not known what function they serve in the fetus in the absence of antigen and ongoing immune responses, although clearly they are not memory cells. [ABSTRACT FROM AUTHOR]

In this paper we report that treatment with 17β-oestradiol depresses cutaneous delayed-type hypersensitivity (DTH) to oxazolone (OXA) in female oophorectomized NZB/W mice. Analysis of the parental strains revealed that this oestrogen-induced inhibition of DTH mice is a trait inherited from the healthy NZW and not from the autoimmune NZB strain. The down-regulating effect of oestradiol on DTH in female NZB/W mice was found both in the sensitization and effector phase of the DTH response. Decreased DTH reactivity to OXA was demonstrated in oophorectomized NZB/W and NZW mice after administration of both low, physiological doses (s.c. injections) and high, pharmacological doses (siliac tube implantation) of oestradiol. In addition, s.c. implantation of testosterone containing siliac tubes suppressed DTH reactivity to OXA in castrated male NZW mice. This down-regulating effect was not found in male NZB or NZB/W mice similarly treated. Serological analysis revealed that high doses of oestradiol increased whereas testosterone depressed the IgG anti-OXA antibody responses in female NZB/W mice. Our results indicate that one possible contribution of the NZW parental strain to the lupus disease in NZB/W mice is a trait of oestrogen sensitivity leading to the acceleration of the autoimmune disease, the latter feature being inherited from NZB mice. [ABSTRACT FROM AUTHOR]

Previous studies have shown that lymphocytes carry cell surface receptors for sulphated polysacchar-ides (SPS), and SPS recognition may play a role in lymphocyte migration and positioning in vivo. This paper describes attempts to isolate and characterize the endogenous glycosaminoglycans (GAGs) of murine spleen and determine whether splenic lymphocytes carry cell surface receptors for these GAGS. A procedure was devised for isolating GAGs from murine spleen in good yield and high purity and the GAG preparation was then radiolabelled for subsequent binding studies. It was found that the splenic GAGs bound to murine splenocytes in a saturable, rapid and reversible manner with only a small subpopulation of the splenic GAG preparation being involved in binding. This reactive species was chondroitinase ABC-resistant and nitrous acid-sensitive, indicative of a heparan sulphate/heparin-like molecule. Furthermore, using immunofluorescent flow cytometry studies it was demonstrated that the majority of spleen cells have receptors for these GAGs. Subsequent ion- exchange fractionation and SDS-PAGE analysis of chondroitinase ABC-resistant GAGs confirmed that the splenic GAG recognized by splenocytes was a heparan sulphate/heparin molecule of approximately 20,000 MW with a binding affinity to splenocytes of approximately 5 × 10-8 M. Additional binding inhibition studies indicated two possible binding sites, for splenic GAGs on the splenocyte surface, one being fully inhibited by a range of SPS such as heparin (both coagulant and anticoagulant forms), pentosan sulphate, fucoidan, dextran sulphate, λ- and t-carrageenan, and the second being partially inhibited by κ-carrageenan. The possible relevance of these heparan sulphate! heparin receptors on splenocytes to lymphocyte positioning in vivo is discussed. [ABSTRACT FROM AUTHOR]

This paper examines the possibility of a functional linkage between class I MHC molecules and the T-cell receptor complex for antigen (T3-Ti). A newly developed anti-CD3 antibody (500A2) was used as an activation signal for EL4 lymphoma cells and allospecific cytotoxic T-cell clones (CTL), and the production of IL-2/IL-2 receptor in EL4 cells and serine esterase in CTL was determined. Anti-CD3 antibody-induced activation of both EL4+ and CTL cells was enhanced in the presence of immunologically cross-linked and immobilized anti-H-2 (class I) antibody reactive against the H-2 haplotype of the responding T cells. A number of H-2-negative and H-2-positive EL4 subclones were generated and tested for anti-CD3 antibody-induced IL-2/IL-2 receptor production. Although both H-2-positive and -negative subclones expressed CD3 antigen and produced IL-2 after activation with the phorbol ester TPA, only the H-2-positive cell clones produced IL-2 and expressed IL-2 receptor after anti-CD3 antibody induction. Our results are compatible with the existence of a functional linkage between the class I and the CD3 molecules on the surface of T cells. [ABSTRACT FROM AUTHOR]

The mechanisms which generate heterogeneity amongst resident tissue macrophages (Mø) are poorly understood. In a previous study we described a novel mouse Mø haemagglutinin, which binds unopsonized sheep erythrocytes. This sheep erythrocyte receptor (SER) is expressed at high levels on stromal Mø from bone marrow and lymph nodes, but at low levels on Mø from serous cavities and broncho-alveolar spaces. In this paper we demonstrate that a species-restricted factor in mouse serum is required in vitro for optimal maintenance of SER on resident bone marrow Mø and for its induction on Mø populations which normally lack this receptor. Using thioglycollate-elicited peritoneal Mø, induction of SER by mouse serum was doses dependent, reached maximal levels by 3- 4 days, required the continuous presence of mouse serum, and was fully reversible. Reexpression following trypsinization was inhibited by cycloheximide, showing that protein synthesis by Mø was necessary. Using a quantitative microtitre plate assay to measure levels of the inducing activity (SER-IA) in different samples, it was found to be heatelabile, non-dialysable, precipitable by polyethylene glycol and inactivated at pH 4 but not at pH 96. On gel filtration of mouse serum, a single major peak of activity was obtained with an apparent MW of around 70,000. SER-IA appears to be unrelated to a variety of factors and cytokines which affect Mø function, including colony-stimulating factors I (CSF-1). The possible role of SER-IA in regulating the differential expression of SER in vivo is discussed. [ABSTRACT FROM AUTHOR]

Pretreatment of EL4 cells with 12-O-tetradecanoyl phorbol- 13-acetate (TPA) for 30 mm renders them resistant to lysis by activated macrophages (Mø). This resistance was augmented two to three-fold when TPA-trated EL4 cells were incubated for 2-6 hr prior to co-culture with Mø. Preincubation of TPA-treated cells for 24 hr could result in 100% resistance. In this paper we show that an endogenous ligand for protein kinase C, oleolyl-2-acetate glycerol (OAG), was capable of inducing tumour cell resistance to Mø kill and, similar to the effects seen with TPA, OAG did not affect the selective binding of tumour cells to activated Mø. Another important observation on the mechanism of TPA induction of tumour cell resistance was that once the target cells were progranuned to die after a minimal contact with activated Mø of 4-6 hr, TPA treatment was ineffective in altering the percent lysis 20 hr later. To investigate whether any possible correlation exists between TPA-induced protein phosphorylation and acquisition of resistance, EL4 cells were labelled with 32P and treated simultaneously with TPA, and cellular proteins were resolved by two adimensional gel electrophoresis. Eight polypeptides (MW 24,000-70,000, p1 48-61) showed consistent increased phosphorylation as a result of WA treatment. One-minute exposure with TPA resulted in enhanced phosphorylation of only four peptides (MW 39,000, 58,000, 63,000, 70,000) while all eight polypeptides showed increased phosphorylation by 10 mm. [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]

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]

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]

An antibody to the V-region of a kI light chain has been used to detect other human sc-chains with similar idiotypic specificitics that appear to be related to complementarity-determining regions (CDR). Four such proteins, three of which react with this antibody, have been sequenced. While the proteins show relatively strong sequence similarities in their CDR2 regions, the relatively high degree of homology in a localized segment of the V-region of A-chains detected by this method was not observed here. [ABSTRACT FROM AUTHOR]

The memory response of BALB/c mice to phosphocholine-keyhole limpet haemocyanin (PC-KLH) consists of two antibody populations, designated Group I and Group II, that differ in their fine specificity, as determined by hapten inhibition using phosphocholine (PC) and p-nitrophenylphos-phocholine (NPPC). It is known that Group I response is dominated by T15 idiotype-positive antibodies that utilize the VH I heavy-chain gene in combination with VK22 light-chain gene. In this paper we show that Group II serum antibodies of BALE/c mice are also highly restricted in their heterogeneity, as determined by N-terminal amino acid sequence analysis. Furthermore, we demonstrate that the Group II response is not affected by neonatally induced T15 suppression, whereas the Group I response in these mice consists of T1 5-negative antibodies. This suggests that the expression of the two antibody populations is regulated independently. Finally, we show that the isotype distributions within a fine specificity are the same in normal and T15-suppressed mice. Interestingly this is true not only for the Group II but also for the Group I antibodies. Because the isolated Group I antibodies from normal mice differ in structure from those of T15-suppressed mice, i.e. different light chains, our data indicate that the isotype distribution of these two populations is associated with their fine specificity in addition to their clonal origin. [ABSTRACT FROM AUTHOR]

A potent immunosuppressor factor, known as SER (suppressive E-receptor factor) has been identified in the body fluids of cancer patients. SER has been proven to be immunochemically analogous to the fetal form of haptoglobin. In this paper, we examine the role of SER immune suppressor in the immune surveillance mechanism of the host, using an affinity-purified SER. As shown in this study, SER, at µg/ml concentrations, inhibits the T-cell proliferation induced with either monoclonal or polyclonal T-cell activators in vitro in human, and also inhibits the primary antibody response to T-dependent antigens in vivo in mice. Likewise, SER also inhibits the immunoglobulin synthesis of human B lymphocytes induced by a B-cell mitogen, pokeweed mitogen, in the presence of a tumour promoter, phorbol myristate acetate (PMA). In contrast to the T-dependent antibody response in vivo in mice or T-dependent mitogen response in vitro in human, SER does not interfere with the T-independent antibody responses to DNP-Ficoll or TNP-LPS in mice. SER also interferes with the natural killer cell function of human peripheral blood mononuclear cells. Although SER inhibits the phagocytic functions of human peripheral neutrophils, it requires at least 10-20 times the concentration of SER present in normal human plasma. Since this concentration of SER is attainable in the sera of solid tumour-bearing patients, highly elevated levels of SER could predispose the patients to microbial infections as well. This study demonstrates that purified SER manifests multi-faceted down-regulatory effects on the defence mechanism of hosts, thereby it could compromise the patients' cell-mediated immunity in vivo. [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]

This paper describes the production and characterization of a panel of 15 mouse monoclonal antibodies selected for putative activity against V-region related or allotypic determinants of a single IgG1λ paraprotein obtained from a patient with malignant lymphoplasmacytoid lymphoma. The specificity of each reagent for epitopes on the heavy (H) or light (L) chain or for conformational determinants (CD) of the immunogen was determined and the ability of one reagent to compete with another for these sites investigated. The fine specificity of the antibodies was assessed by screening on a large series of normal and paraprotein-containing sera. One monoclonal showed specificity for the Glm(f) allotype. The 14 other reagents identified a minimum of nine different epitopes in the V region of the immunogen, with four antibodies detecting private conformationally determined idiotypic specificities. Eight determinants were V-region markers also expressed on other paraproteins. A total of 30 out of 159 different paraproteins cross-reacted with one or more of the antibodies. Four of the shared epitopes were λ-chain associated, three were H-chain associated and one was a conformational determinant. Homologies of λ chain were identified more frequently among other paraproteins than those of H chain. The relationship between epitope expression and H-chain class of paraprotein was not random. The frequency of expression of cross-reactivities in association with IgG1 proteins was always exceeded by higher frequency of epitope expression in association with other classes of H-chain isotype. The potential therapeutic value of such panels of characterized monoclonal reagents is discussed. [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]

A factor found in the serum of patients with leprosy that inhibits the growth of mitogen-stimulated normal peripheral blood lymphocytes has been studied. The inhibitor, previously identified as an IgG, has been shown to act by blocking the recruitment of lymphocytes into growth. It was not cytotoxic and did not inhibit the rate of growth of those lymphocytes that had been stimulated. The inhibitory activity was less potent if the serum was added after mitogen stimulation. The inhibitor, which could be absorbed by activated but not resting lymphocyte cultures, appeared to act by inhibition of an early event preceding the release of IL-2. The inhibition of mitogen stimulation was overcome by the addition of purified IL-2, although the inhibitor did not block the action of IL-2 on a long-term cultured IL-2-dependent cell line. [ABSTRACT FROM AUTHOR]

This paper describes the activity of a bacterial surface component (capsular material, CM) in biological assays for interleukin-l (IL-1). CM from the periodontal pathogen Hoemophilus actinomycetemcomitans was tested in the following in vitro assays: mouse thymocyte proliferation (LAF assay), stimulation of collagenase and prostaglandin (PG) E2 synthesis by articular chondrocytes, and stimulation of PGE2 synthesis by fibroblasts. In all these assays, CM gave a response similar to an IL-1 preparation. This ability to mimic IL-1 suggests an important role for CM in both cell-mediated immunity and connective tissue destruction in localized juvenile periodontitis (LJP). [ABSTRACT FROM AUTHOR]

Natural killer (NK) activity is inhibited by the contact of peripheral blood lymphocytes with primary monolayer cell cultures of both benign and malignant origin. In this study the effect of interferons (IFNs) on the inhibition has been analysed. Both αIFN- and γIFN-pretreated peripheral blood lymphocytes are effectively inhibited by monolayer target cells. IFN treatment of lymphocytes does not change cytotoxicity against the inhibitory target cells, although it enhances reactivity against NK-sensitive target cells. Treatment of monolayer cells with interferons significantly reduces their inhibitory capacity. However, diminished inhibition of NK activity by the IFN-treated target cells is not associated with increased lysis, probably due to their decreased sensitivity to natural killer cytotoxic factors (NKCF). In 18.5% of the cases studied, monolayer target cells induced endogenous IFN production in lymphocytes. in these cases no inhibition of the NK activity of the effector cells was seen. According to the results of this paper, IFNs have a dual effect on the NK regulatory system: they enhance the NK activity of the effector cells against NK-sensitive target cells, and they change the NK resistant target cells in a way that makes them less inhibitory to NK activity but simultaneously more resistant to the toxic factors secreted by NK cells. [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]

Reagents for the identification of rabbit cell markers have been developed at a relatively slow rate. In this paper, rabbit cells are being characterized by polyclonal antibodies against a Tall antigen (RTLA), a B-cell antigen (RABELA) and an analogue of murine Ia antigen. A number of monoclonal antibodies, specific for lymphocytes and/or bone marrow and/or polymorphonuclear leucocytes, have been used for the analysis of cells with identifiable membrane antigens. Populations that have cells with two of the above antigens in the membranes were identified. To these ends, complement-mediated cell kill by antisera alone and in mixtures was employed. [ABSTRACT FROM AUTHOR]

The expression of a diverse array of receptors for sulphated polysaccharides on lymphocytes has been demonstrated by Parish & Snowden (1985). This paper presents evidence to suggest that other cell types, namely macrophages, polymorphonuclear leucocytes, mast cells and fibroblasts, can bind similar polysaccharides. Using a rosetting assay and eleven structurally unique polysaccharides, each cell type was observed to bind a characteristic array of these polysaccharides. Analysis of the polysaccharide reactivity of macrophages revealed that BCG-activated and thioglycollate-elicited macrophages express an expanded repertoire of reactivity compared to resident peritoneal macrophages. For example, only thioglycollate-elicited macrophages, but not resident and BCG-activated peritoneal macrophages, reacted with the glycosaminoglycans, chondroitin-4-sulphate, chondroitin-6-sulphate and dermatan sulphate, while both BCG- and thioglycolate-activated, but not resident peritoneal macrophages, bound pentosan polysulphate-coupled sheep erythrocytes. The expression of the receptors for chondroitin-4- and -6-sulphate was observed to be cyclic and peaked at 2 and 5-6 days after thioglycollate treatment. Preliminary analyses of the functional significance of the observed binding of polysaccharides to macrophages revealed that heparin, fucoidan and kappa-carrageenen were specifically endocytosed. However, endocytosis of all other test polysaccharides was not observed. Finally, polysaccharide-coupled sheep erythrocytes were not phagocytosed, even though they interacted strongly with the macrophage surface. The possible relevance of these observations to an inflammatory response and as a means of identifying cellular subsets is discussed. [ABSTRACT FROM AUTHOR]

In this paper we describe production of alloantisera specific for determinants encoded by I-J gene loci expressed on macrophages. B10.A(3R) (l-Jb) mice were hyperimmunized with pure populations of macrophages grown in vitro from bone marrow stem cells of congenic B10.A(5R) mice. The antisera contained predominantly IgM antibody that was non-adherent to protein-A-Sepharose with a minor component of IgGI, and IgG2a antibodies that were adherent to protein.A-Sepharose. The protein- A non-adherent antibody completely blocked the in vitro generation of humoral immune responses to sheep erythrocytes by spleen cell from B10.A(5R) mice and from inbred strains that share the I-Jk haplotypes, but did not alter the responses of spleen cells of the I-Jb haplotype. In the presence of complement. both protein-A adherent and protein-A non-adherent antibodies eliminated the capacity of B10.A(5R) spleen cells to generate humoral and proliferative responses, but the functional activity of B10.A(3R) cells was unaffected. These data indicate the I-Jk specificity of the antisera. The capacity of the anti-macrophage antibody to block humoral immune induction was removed by absorption with bone marrow-derived macrophages from B10.A(5R) mice, but not from B10.A(3R) mice. Further, the B10.A(5R) macrophages completely restored the humoral responses of antibody- and complement-treated B10.A(5R) spleen cells, but B10.A(3R) macrophages showed only partial restoration that was consistent with a factor-mediated allogeneic effect. These data demonstrate the specificity of our anti-I-J sera for macrophages and indicate that bone marrow-derived macrophages express surface I-J encoded molecules. [ABSTRACT FROM AUTHOR]