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This paper describes the spontaneous occurrence of an autoimmune uveoretinitis in nude (nu/nu) mice reconstituted when 4 weeks old by the grafting of rat embryonic thymus. The uveoretinitis was characterized histologically by progressive loss of the photoreceptor layer, observed in 4.0, 17.6, 42.9% and 71.4% of such mice at 3, 5, 7 and 12 months of age, respectively. Mice with uveoretinitis were shown to have serum IgG antibody reactive by indirect immunofluorescence with retinal photoreceptors, and with interphotoreceptor retinoid-binding protein (IRBP), but not retinal S-antigen, by immunoblotting and ELISA. A uveoretinitis could be adoptively transferred to syngeneic ungrafted nude mice by splenic CD4+ T cells from diseased animals. This is the first experimental model of a (T cell mediated) autoimmune uveoretinitis which develops spontaneously and which is not dependent upon deliberate sensitization with retinal antigens and adjuvants. [ABSTRACT FROM AUTHOR]

Peripheral blood mononuclear cells from patients with Sjögren's Syndrome spontaneously secrete autoantibodies to the La antigen when cultured in vitro. This paper reports that specific IgG autoantibody production in vitro is suppressed by pre-treatment of CD8+ enriched T cells with rabbit polyclonal antibodies to idiotypes borne by circulating autologous anti-La antibodies. Treatment of this T cell subpopulation with anti-idiotypes specific for circulating anti-La antibodies from other patients or for anti-DNA antibodies was without effect on anti-La antibody production. Similarly anti-La anti-idiotypes had no effect on the production of autoantibodies to other ribonucleoprotein antigens such as nRNP/Sm. These data show that CD8+ T cells are the main targets for anti-idiotypic control in vitro. We suggest that the relative deficit of these cells, plus a surfeit of CD4+ T cells at the site of the pathological lesion within the salivary gland permits localized production of autoantibodies. Thus, dysregulation of the idiotypic network could contribute to the pathogenesis of Sjögren's Syndrome. [ABSTRACT FROM AUTHOR]

The antigen-induced DNA synthesis in vitro in lymphocytes from patients with acute Plasmodium falciparum malaria was investigated. The patients and healthy controls from Sweden or Colombia were the same as those studied in the accompanying paper (Troye-Blomberg el al., 1983). The malarial antigens used were sonicated membrane preparations or purified and concentrated supernatants from in vitro cultures of P. facliparum, similar preparations derived from normal human erythrocytes served as control antigen. In the patients' lymphocytes P. falciparum antigens induced a weak or moderate but significant stimulation of DNA synthesis, peaking after 3-4 days of incubation. This early response was specific for P. faleiparum since it was not obtained with lymphocytes from healthy donors nor with those from patients with acute P. vivax or P. ovale malaria. No antigen-induced response was seen in about half of the P.falciparum patients. However in a few negative eases, available for consecutive testing, positive reactions were seen with lymphocytes taken 2 weeks after infection when the blood of these patients was free of parasites. The early response induced in patients' lymphocytes to the P. falciparum antigens was not obtained with RBC antigen, however, these preparations frequently induced a response rising to significant levels later during incubation (day 5-6)- Similar delayed responses were obtained when either- patients' or control donors' lymphocytes were exposed to the P. falciparum antigens. This indicates that both the RBC and the parasite preparations contained mitogenic substances affecting human lymphocytes in general and easily obscuring the P, falciparum specific responses seen only in the patients. This latter response was relatively low and short lived, suggesting that it reflected a secondary in vitro stimulation of in vivo primed lymphocytes and that it was regulated by suppressor mechanisms. [ABSTRACT FROM AUTHOR]

Lack of serum IgG2, IgA and IgE was found in a healthy male adult blood donor. No secretory IgA could be demonstrated. In vitro activation of lymphocytes did not induce IgA secreting cells although no class specific suppressor cells could be found. Normal or slightly subnormal titres to a variety of bacterial and viral antigens were demonstrated whereas anti-carbohydrate antibodies (anti-teichoic acid, anti-dextran and anti-pneumococcal polysaccharide) were virtually absent. Isoagglutinins and heteroagglutinins were present in somewhat lower concentrations than normal. [ABSTRACT FROM AUTHOR]

Persistent inflammatory response in cystic fibrosis (CF) airways is believed to play a central role in the progression of lung damage. Anti-inflammatory treatment may slow lung disease progression, but adverse side effects have limited its use. Vitamin D has immunoregulatory properties. We randomized 16 CF patients to receive vitamin D2, vitamin D3 or to serve as controls, and investigated the effect of vitamin D supplementation on soluble immunological parameters, myeloid dendritic cells (mDCs) and T cell activation. Three months of vitamin D treatment were followed by two washout months. Vitamin D status at baseline was correlated negatively with haptoglobin, erythrocyte sedimentation rate and immunoglobulin A concentration. Total vitamin D dose per kg bodyweight correlated with the down-modulation of the co-stimulatory receptor CD86 on mDCs. Vitamin D treatment was associated with reduced CD279 (PD-1) expression on CD4+ and CD8+ T cells, as well as decreased frequency of CD8+ T cells co-expressing the activation markers CD38 and human leucocyte antigen D-related (HLA-DR) in a dose-dependent manner. There was a trend towards decreased mucosal-associated invariant T cells (MAIT) cell frequency in patients receiving vitamin D and free serum 25-hydroxyvitamin D (free-s25OHD) correlated positively with CD38 expression by these cells. At the end of intervention, the change in free-s25OHD was correlated negatively with the change in CD279 (PD-1) expression on MAIT cells. Collectively, these data indicate that vitamin D has robust pleiotropic immunomodulatory effects in CF. Larger studies are needed to explore the immunomodulatory treatment potential of vitamin D in CF in more detail. [ABSTRACT FROM AUTHOR]

Regulatory T cells ( Tregs) are known to play an immunosuppressive role in the response of contact hypersensitivity ( CHS), but neither the dynamics of Tregs during the CHS response nor the exaggerated inflammatory response after depletion of Tregs has been characterized in detail. In this study we show that the number of Tregs in the challenged tissue peak at the same time as the ear-swelling reaches its maximum on day 1 after challenge, whereas the number of Tregs in the draining lymph nodes peaks at day 2. As expected, depletion of Tregs by injection of a monoclonal antibody to CD25 prior to sensitization led to a prolonged and sustained inflammatory response which was dependent upon CD8 T cells, and co-stimulatory blockade with cytotoxic T lymphocyte antigen-4-immunoglobulin ( CTLA-4- Ig) suppressed the exaggerated inflammation. In contrast, blockade of the interleukin ( IL)-10-receptor ( IL-10 R) did not further increase the exaggerated inflammatory response in the Treg-depleted mice. In the absence of Tregs, the response changed from a mainly acute reaction with heavy infiltration of neutrophils to a sustained response with more chronic characteristics (fewer neutrophils and dominated by macrophages). Furthermore, depletion of Tregs enhanced the release of cytokines and chemokines locally in the inflamed ear and augmented serum levels of the systemic inflammatory mediators serum amyloid ( SAP) and haptoglobin early in the response. [ABSTRACT FROM AUTHOR]

Sepsis is a life-threatening condition, but the pathophysiological basis and biomarkers for the monitoring of sepsis and as targets for therapy remain to be determined. We have shown previously that T cell immunoglobulin and mucin domain protein 3 ( Tim-3), a negative immune regulator, is involved in the physiopathology of sepsis, but the underlying mechanisms remain unclear. In the present study, we showed that Tim-3 signalling modulated the response patterns of both macrophages and T helper cells in sepsis. Blockade of the Tim-3 pathway exacerbated sepsis-induced proinflammatory macrophage responses and lymphocyte apoptosis during the early phase of sepsis, and enhanced the shift to anti-inflammatory responses for both macrophages and T helper cells during the late phase of sepsis. Tim-3 signalling was found to regulate CD80 and CD86 expression on macrophages both in vivo and in vitro. Co-culture of T cells with Tim-3 knock-down macrophages led to a biased T helper type 2 ( Th2) response, partially explaining how Tim-3 signalling shapes inflammation patterns in vivo. Further studies on this pathway might shed new light on the pathogenesis of sepsis and suggest new approaches for intervention. [ABSTRACT FROM AUTHOR]

The expansion of regulatory T cells ( Treg) controls inflammation in children with acute Kawasaki disease ( KD). Blockade of tumour necrosis factor ( TNF)-α is an emerging therapy for KD patients with refractory inflammation, but there is concern that this therapy could impede the host immune regulation. To define the effect of TNF-α blockade, we conducted ex-vivo immune-monitoring in KD subjects who participated in a randomized, double-blind, placebo-controlled clinical trial of the addition of infliximab to standard intravenous immunoglobulin ( IVIG) therapy. We enumerated circulating myeloid and plasmocytoid dendritic cells ( DC), regulatory T cells ( Treg) and memory T cells ( Tmem) in 14 consecutive, unselected KD patients (seven treated with IVIG, seven with IVIG + infliximab) at three time-points: (i) acute phase prior to treatment, (ii) subacute phase and (iii) convalescent phase. Myeloid DC ( mDC), but not plasmacytoid DC ( pDC), were numerous in the peripheral blood in acute KD subjects and decreased in the subacute phase in both IVIG− and IVIG + infliximab-treated groups. The co-stimulatory molecule for antigen presentation to T cells and CD86 decreased in mDC from acute to subacute time-points in both treatment groups, but not in the single patient who developed coronary artery aneurysms. We also defined tolerogenic mDC that expand in the subacute phase of KD not impaired by infliximab treatment. Treg and Tmem expanded after treatment with no significant differences between the two groups. Treatment of KD patients with infliximab does not adversely affect generation of tolerogenic mDC or the development of T cell regulation and memory. [ABSTRACT FROM AUTHOR]

Epidermolysis bullosa acquisita is an autoimmune blistering disease characterized by circulating and skin basement membrane-bound IgG autoantibodies to type VII collagen, a major structural protein of the dermal–epidermal junction. Regulatory T cells (Treg) suppress self antigen-mediated autoimmune responses. To investigate the role of Treg in the the autoimmune response to type VII collagen in a mouse model, a monoclonal antibody against mouse CD25 was used to deplete Treg. A recombinant mouse type VII collagen NC1 domain protein and mouse albumin were used as antigens. SKH1 mice were used as a testing host. Group 1 mice received NC1 immunization and were functionally depleted of Treg; group 2 mice received NC1 immunization and rat isotype control; and group 3 mice received albumin immunization and were functionally depleted of Treg. Results demonstrated that anti-NC1 IgG autoantibodies with high titres, as determined by enzyme-linked immunosorbent assay and Western blotting, developed in all mice immunized with NC1 (groups 1 and 2), but were undetected in group 3 mice. The predominant subclasses of anti-NC1 autoantibodies were IgG1, IgG2a and IgG2b; furthermore, these antibodies carried only the kappa light chain. IgG autoantibodies in the sera of NC1-immunized mice reacted with mouse skin basement membrane in vitro and deposited in skin basement membrane in vivo as detected by indirect and direct immunofluorescence microscopy, respectively. Our data suggest that the development of autoimmunity against type VII collagen in mice is independent of Treg function and the autoimmune response is mediated by both Th1 and Th2 cells. We speculate that the basement membrane deposition of IgG may eventually lead to blister development. [ABSTRACT FROM AUTHOR]

The aetiology of Crohn's disease (CD) remains unknown. Since SAMP1/Yit mice have been reported to develop CD-like spontaneous enteric inflammation, such mice have been studied as an animal model of CD. In this study, using this model we examined T lymphocyte migration in microvessels of intestinal mucosain vivoand the expression of adhesion molecules by immunohistochemistry. Fluorescence-labelled T lymphocytes isolated from AKR/J (control) mice were injected into the tail veins of recipient mice, and T lymphocyte migration in the postcapillary venules of Peyer's patches, submucosal microvessels, and villus capillaries of the terminal ileum was monitored using an intravital microscope. Adhesion of T lymphocytes was significantly increased in 35 week old SAMP1/Yit mice compared with that in AKR/J or 15 week old SAMP1/Yit mice. Immunohistochemical study showed increased infiltration of CD4, CD8 andβ7-integrin-positive cells and increased expression of MAdCAM-1 and VCAM-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against MAdCAM-1 and VCAM-1 significantly inhibited adhesion of T lymphocytes to microvessels of the terminal ileum, and anti-MAdCAM-1 antibody showed stronger suppressive effect than the anti-VCAM-1 antibody. Periodical administration of anti-MAdCAM-1 antibody twice a week for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice, but submucosal hypertrophy was not significantly suppressed. Anti-VCAM-1 antibody treatment failed to show significant resolution of ileitis. In addition, anti-MAdCAM-1 antibody treatment also attenuated established ileitis. The results demonstrate that, although MAdCAM-1 and VCAM-1 play an important role in T lymphocyte–endothelial cell interactions in SAMP1/Yit mice, MAdCAM-1 may be a more appropriate target for therapeutic modulation of chronic ileitis. [ABSTRACT FROM AUTHOR]

Eleven Norwegian patients (aged 2–33 years, seven males and four females) with Ataxia-telangiectasia (A-T) and their parents were investigated. Five of the patients were homozygous for the same ATM mutation. 3245delATCinsTGAT, a Norwegian founder mutation. They had the lowest IgG2 levels: mean (95% confidence interval) 0·23 (0·05–0·41) g/l versus 0·91 (0·58–1·26) g/l in the other patients (P= 0·002). Among the 11 A-T patients, six had IgG2 deficiency, six had IgA deficiency (three in com- bination with IgG2 deficiency) and seven had low/undetectable IgE values. All patients had very low levels of antibodies to Streptococcus pneumoniae 0·9 (0·4–1·4) U/ml. while normal levels were found in their parents 11·1 (8·7–13·4) U/ml (P < 0·001). A positive linear relationship between pneumococcal antibodies and IgC2 (r = 0·85, P = 0·001) was found in the patients. Six of 11 had diphtheria antibodies and 7 of 11 tetanus antibodies after childhood vaccinations, while 4 of 7 Hemophilus influenzae type b (Hib) vaccinated patients had protective antibodies. Ten patients had low B cell (CDI9+) counts, while six had low T cell (CD3+) counts. Of the T cell subpopulations, 11 had low CD4+ cell counts, six had reduced CD8+ cell counts, and four had an increased portion of double negative (CD3+/CD4-/CD8-) gamma delta T cells. Of the 22 parents (aged 23–64 years) 12 were heterozygous for the ATM founder mutation. Abnormalities in immunoglobulin levels and/or lymphocyte subpopulations were also observed in these carriers, with no correlation to a special ATM genotype. [ABSTRACT FROM AUTHOR]

CVID is characterized by hypogammaglobulinaemia and impaired antibody production. Previous studies demonstrated defects at the T cell level, In the present study the response of purified CD4+ and CD8+ T lymphocytes to stimulation with anti-TCR monoclonal antibody (the first signal) in combination with anti-CD4 or anti-CD8. anti-CD2 and anti-CD2S MoAbs (the costimulatory signals) was investigated. Both CD4+ and CDS+T cells from the patients showed significantly reduced IL-2 release following stimulation via TCR and costimulation via CD4 or CDS and CD2. respectively. However, normal lL-2 production following TCR plus phorbol myristate acetate (PMA) costimulation and normal expression of an early activation marker. CD69. after TCR +CD28 stimulation indicated that TCR was able to transduce a signal. Furthermore, both IL-2 and la-4 release were impaired in CD4+ lymphocytes following TCR + CD28 stimulation. In addition, stimulation via TCR + CD28 resulted in significantly decreased expression of CD40 ligand in the patients. These results suggest that the integration of activating signals derived from the TCR and costimulatory molecules is defective in CVID patients; the defect is not confined to costimulation via a single molecule. or restricted to cells producing Th1-type cytokines such as IL-2. and is expressed in both CD4+ and CDS+T cell subsets. [ABSTRACT FROM AUTHOR]

Considerable effort is being invested in antibody gene technologies for production of species-adapted anti-T cell antibodies which can overcome formation of neutralizing anti-antibodies (anti-Ab). By establishing a mouse model for the generation of syngeneic anti-T cell MoAb. We addressed the question of whether ideally species-adapted T cell-binding antibodies can prime mice to produce anti- Ab, Two anti-Thy-1.2 MoAbs of IgG2a (MmTC) or IgM (MmTC-IgM) isotype were generated in congenic C57Bl/6-Thy-l.l mice. Three injections of MmTC in C57B1/6-Thy-l.2 or (C57Bl/6-Thy-1.2×C57B1/6-Thy-l.l)F2 hybrids where they act as syngeneic anti-T cell MoAbs induced low anti-Ab. When MmTC was injected as Igh-mismatched antibody in CBA/J mice, high titre anti-MmTC antibodies were measured and fully mismatched skin allografts rejected within 26 days. MmTC injected twice weekly in syngeneic C57B1/6 mice induced low anti-MmTC and prolonged graft survival up to day 117. In contrast, retreatment induced anti MmTC with graft rejection within 32 days. Thus, upon retreatment, the immunosuppressive effects of MmTC were inhibited to a similar extent as that seen after antibody treatment in Igh-mismatched mice. However, a recently analysed immunological principle to suppress anti-Ab against T cell binding allo- or xenoantibodies by preinjection of T cell-depleting antibody with species differences in heavy chains also suppressed syngeneic anti-Ab after MmTC retreatment. This effect was accompanied by prolonged graft survival. Thus, our data indicate that inhibitory anti-Ab must be considered in humans even when treated with fully species-adapted anti-T cell MoAb, but may be suppressed by preinjection of a Fc region-mismatched anti-T cell antibody. [ABSTRACT FROM AUTHOR]

We studied T cell responses to four glutathione S transferase (GST)-fused mite antigens prepared in our laboratory using peripheral blood lymphocytes from mite-sensitive patients with bronchial asthma. Of the four recombinant antigens, purified GST-Mag3 had the strongest ability to cause patients' lymphocytes to proliferate, and its potency was almost comparable to that of crude mite bodies (Dfb) and faeces (Dff) antigens and a purified major antigen, Der f 2. The responder lymphocytes were mainly T cells, because the proliferative response was depleted by the treatment of lymphocytes with anti-CD3 antibody and complement, but not with anti-CD20 antibody and complement. The responsiveness of lymphocytes to GST-Mag3 correlated with that to Der f 2, but GST-Mag3 displayed slightly higher activity to stimulate lymphocytes than Der f 2. Simultaneously, the levels of Dff- and GST-Mag3- specific IgE antibodies correlated with the responsiveness of lymphocytes to GST-Mag3. These results suggest that Mag3 is a new valuable antigen for the response of T cell proliferation in mite-sensitive patients. [ABSTRACT FROM AUTHOR]

Anti-endothelial and other cell membrane-reactive antibodies in scleroderma were characterized by immunoblotting sera with membrane and cytosol preparations of human umbilical vein endothelial cells (HUVEC). dermal fibroblasts and a T cell lymphoma HUT78. Antibodies reactive with HUVEC membranes were found in 17 of 20 patients with scleroderma (33 bands) in contrast to only two of 20 controls (two bands; P < 0.01) and three of 11 patients with myocardial infarction (four bands). Eleven of the 20 patients possessed antibodies that were specific for HUVEC membrane and did not cross-react with other cell lines. Analysis of patient subgroups showed that HUVEC membrane antibodies were present in nine of 11 patients with systemic sclerosis and in all nine with the CREST syndrome, and were HUVEC-specific in five and six of these cases, respectively. Although considerable heterogeneity was seen, antibodies to an 18-19-kD membrane epitope were found in 11 of the 20 patients but in none of the controls (P < 0.01). This antibody which reacted particularly with HUVEC (n = 9) and HUT78 membranes (n = 9) was associated with CREST syndrome rather than systemic sclerosis (9/9 versus 1 /11 ; P<0.01), and after elution was shown to possess anticentromere activity. In addition, antibodies reactive with both fibroblast (n = 11; 18 bands) and HUT78 membranes (n = 18; 42 bands) were detected and were specific for either fibroblast or HUT78 membranes in nine and 14 patients, respectively. There was no significant difference in the incidence of these fibroblasts and HUT78 membrane antibodies in the two patient subgroups. These findings support the concept that membranereactive antibodies, including anticentromeric antibodies, may play a central role in the pathogenesis of scleroderma, through their ability to react with endothelial cells. [ABSTRACT FROM AUTHOR]

Activation antigens (actags) were detected on T cells at low levels of intensity by carefully defining negative cells with a panel of control antibodies. The mean percentage of blood T cells from healthy volunteers that expressed actags were 22% (CD25), .54% (CD26), 38% (CD38), 12% (CD54), 6% (CD69)and 21% (HLA-DR). The variability of actag expression detected by this sensitive method was determined on healthy volunteers by repeated estimation over a year. The percentage of T cells expressing CD25 and CD26 varied no more than repeated estimation of the CD4 T cell subset, whereas other actags showed greater variability. The antigen density of these actags on T cells was determined in relation to CD4 antigen density, and for most actags ranged from 10% to 75% of the level of CD4 antigen density except for CD7 and HLA-DR. which could exceed that of CD4. Different degrees of actag expression characterized T cells from different blood and lymphoid tissues. CD26. CD38 and CD45RA were universally expressed in cord blood at higher antigen density than adult blood. This immature pattern was consistent with recent thymic emigration. CD25, CD45RO, CD54 and HLA-DR progressively increased from cord blood through adult blood to lymphoid tissues, consistent with antigen-driven activation, whereas CD26 and CD45RA decreased. CD69, a very early activation antigen, abruptly increased in lymphoid tissue, exceeding CD25 by two-to-three-fold and suggesting a pre-activation state that may not involve commitment to antigen-driven proliferation. CD7 and CD38 expression was higher in cord blood and lymphoid tissue than in adult blood, indicating both an antigen-independent and -dependent up-regulation. [ABSTRACT FROM AUTHOR]

This study pertains to classification and antigenic analysis of mycobacterial plasma membrane proteins in relation to human T cell proliferative responses, using a 'fast grower' Mycobacterium fortuitum as model. Membrane vesicles, prepared by sonication and differential centrifugation, were subjected to biphasic Triton X-114 extraction for isolation of integral (detergent phase) and peripheral (aqueous phase) proteins. Neither protein pool showed any appreciable overlap serologically. SDS-PAGE showed five prominent bands in peripheral and three in the integral protein pool, whereas immunoblotting with rabbit antisera identified only two major antigens (60 and 67 kD) in the former and five (24. 34, 42, 51 and 54 kD) in the latter, ELISA with a panel of anti-mycobacterial MoAbs revealed that nine out of 2 previously known antigens were present in the peripheral protein pool. Only two of them (33 and 40 kD) were additionally detected amongst integral proteins. The membrane-associated immunosuppressive moiety lipoarabinomannan was semiquantitatively located in aqueous phase. In bulk T cell proliferation assays, seven out of 10 subjects belonging to a 'responder" background (BT-BB leprosy patients and healthy contacts) showed high responses for Myco. foruiitum antigens. Proliferative response with integral proteins was comparable to that with whole membrane, but it was significantly higher (P < 0.0005) than the response with peripheral proteins. The distinction and relevance of integral membrane proteins as a class of mycobacterial antigens make them worthy of consideration in a subunit vaccine design. [ABSTRACT FROM AUTHOR]

During dengue type 2 virus (DV) infection of mice a unique cytokine, the cytotoxic factor (CF), is produced which reproduces the pathological lesions seen in patients of dengue haemorrhagic fever (DHF). Recently we have observed a CF-like protein in the sera of DHF cases. The present study was undertaken to investigate whether DV can stimulate human peripheral blood monoclear cells (PBMC) in vitro to produce human CF (hCF). Cultures prepared from PBMC or its enriched subpopulations were inoculated with 1000 LD50 of DV and controls with normal mouse brain suspension (NMB). Aliquots of cultures were harvested daily from 24 h to 96 h and their supernatant (CS) and cells were separated. CS were screened for viral titres and for the presence of hCF by cytotoxicity assay, inhibition ELISA, dot blot and Western blot tests using anti-mouse-CF antibodies. The RNA from the cells was screened in Northern blot and dot blot tests for the presence of mRNA for CF. It was observed that hCF appeared in the CS of DV-infected culture of PBMC and T-enriched cells at 48 h and was present until 96 h; no CF was detected in CS of B cells or monocyte cultures. The production of hCF was abrogated by pretreatment of the T cells with anti-CD4 antibodies but not with anti-CDS antibodies, indicating that hCF was produced by CD4+ T cells. The Northern blot analysis using oligonucleotide probes prepared on the basis of amino-terminal sequence of mouse CF, showed presence of mRNA for hCF in PBMC and T cell cultures. DV replicated in PBMC cultures with peak titres at 48 h. The findings of the present study demonstrate that DV-induced hCF is produced by human T cells. [ABSTRACT FROM AUTHOR]

The T cell response to different Leishmania donovani antigens was investigated using peripheral blood mononuclear cells (PBMC) from Kenyans cured of visceral leishmaniasis and non-exposed Danes. Crude promastigote and amastigote antigens both induced proliferation and interferon-gamma (IFN-γ) production in PBMC from cured patients, while cells from non-exposed donors gave weak responses. A similar pattern was induced by lipophosphoglycan-associated protein (LPGAP). By contrast, the major surface protease of Leishmania, gp63, induced only a weak proliferative response without IFN-γ production in five of 17 samples from cured patients. Four of the five responding cultures produced IL-4, i.e. the response to this antigen was of the Th2 type. Furthermore, sera from acutely ill visceral leishmaniasis patients contained high levels of IgG antibodies to gp63. The Th2-like response to gp63 in patients cured of visceral leishmaniasis differs from the Th1-like response to the same antigen observed in patients cured of cutaneous leishmaniasis. [ABSTRACT FROM AUTHOR]

A wide spectrum of different immunologic abnormalities have been postulated as being responsible for the impairment of specific antibody production and the decrease in all or selected immunoglobulin isotypes present in common variable immunodeficiency (CVID). These abnormalities include impaired B cell differentiation and/or function, defective macrophage function, and significant T cell defects. The aim of the present study was to delineate whether the accessory molecule CD28 is involved in the impaired antigen response of T cells from patients with CVID. Our results demonstrate that CD28 costimulation was functional in T cells stimulated with anti-CD3 or anti-TCR MoAb, but could not correct the impaired response of patients' peripheral blood T cells to tetanus toxoid. Analysis of patients' long-term cultured T cells further confirmed these results. Exogenous rIL-2, another costimulus, augmented but did not correct the defective proliferation and lymphokine production in patients' antigen-driven peripheral blood T lymphocytes or in long-term cultured T cells. These findings indicate that the CD28 signalling pathway in these patients' T cells is unimpaired, and that costimulation via C'D28 cannot correct the defect occurring in the course of TCR-mediated T cell activation. [ABSTRACT FROM AUTHOR]

We have adapted the enzyme-linked immunospot assay (ELISPOT) to enumerate the cells from Plasmodium falciparum-primed donors that produce IgG in vitro in response to malaria antigens. In vitro activation of cell cultures with two synthetic peptides (EENVEHDA)4, and (LGRSGGDIIKMQTL) corresponding to immunodominant T cell epitopes of the ring-infected erythrocyte surface antigen (Pf 155/RESA) gave specific antibody-secreting cells (ASC) in five and six of the 15 P. falciparum-primed donors from Cameroon, Antibodies produced after a stimulation by synthetic peptides reacted also with total parasite proteins. However, crude P. falciparum antigen did not trigger a higher number of cells than did synthetic peptides. The absence of significant relation between the presence of sera antibodies and in vitro ASC against the same peptide suggests that the kinetics of circulating primed lymphocytes and antibodies are different. We evaluated 0.04-0.29% of peripheral blood B cells to be the frequency of memory cells specific to a single Pf155/RESA epitope in these donors. This study suggests that the ELISPOT assay should permit the analysis of B cell responses to malarial antigens at the single-cell level and its applicability to epidemiological field studies. This assay should be well suited to the identification of T helper epitopes capable of inducing the production of antibodies by human B cells, and will constitute an important tool for the selection of immunogens to be included in a subunit vaccine. [ABSTRACT FROM AUTHOR]

The recent report that anti-gpl20 antibodies can be induced by allogeneie stimuli in experimental animals in the absence of HIV. has focused attention on the structural similarities between gpl 20 and MHC. Here we report that some HIV individuals develop antibodies which similarly react with the gpl20 HIV sequence (aa 254 263) and with the HLA-DR /(chains (aa 142-151). As these two peptides share a high level of similarity, we have investigated the role of this gpl 20 region on HLA class II mediated T ceil recognition. The synthetic peptide corresponding to the gpl20 HIV sequence aa 254-263 has been tested on T cell line (TCL) activation. Both the PPD-specific and the self-HLA reactive TCL proliferation increased in the presence of this peptide. Prepulsing experiments indicate that this enhancing effect carried out by HIV peptide is exerted at the level of antigen presentation. Moreover, the specificity of this interaction is supported by the fact that a MoAb specific for this HIV peptide blocked the autoreactive TCL proliferation, similarly lo the inhibition carried out by anticlass II antibody. These data support the hypothesis that the functional homology between the HIV peptide and the HLA β chain described may be involved in the pathogenesis of AIDS. [ABSTRACT FROM AUTHOR]

CD4+ (helper/inducer) T lymphocyte subsets were studied in the peripheral blood from patients with mixed connective tissue disease (MCTD) by double-labelling immunofluorescence. The proportion of CD4+CD45RA+ cells was higher (P < 0.01) when compared with controls, whereas CD4+CD29+ cells were markedly diminished (P<0.001). CD4+CD29+ cells were lower than in patients with progressive systemic sclerosis who were studied in parallel. Upon stimulation with phytohaemagglutinin, CD4+ cells from MCTD patients showed a strong reactivity to acquire the CD29+ phenotype. Expression of high levels of CD29 and other adhesion molecules might lead to facilitated localization of CD4+ cells to inflamed tissue. It is suggested that an increased responsiveness of CD4+ cells to activation signals in vivo and accumulation of CD4+CD29+ cells at tissue sites could result in depletion of this cell subset in the peripheral blood of patients with MCTD. [ABSTRACT FROM AUTHOR]

Human umbilical vascular endothelial cells (HUVEC) express HLA class II molecules upon stimulation with recombinant human interferon-gamma (IFN-γ). Staphylococcal enterotoxin (SE) A (SEA)-binding assay using [125]-SEA showed the presence of specific SEA binding in HUVEC stimulated with IFN-γ but not in unstimulated HUVEC, Levels of HLA class 11 expression and SEA binding increased as the IFN-γ concentration and the period of stimulation were increased. Binding of [125I]-SEA to the IFN-γ-stimulated HUVEC was reduced markedly by an anti-DR/DP MoAb. T cells produced IL-2 upon stimulation with a group of SEs (SEA, SEB, SEC, SED and SEE) in the presence HUVEC stimulated with IFN-γ but not in the presence of control HUVEC. The level of accessory cell activity in the IFN-γ-stimulated HUVEC was related lo the level of HLA class II expression and SEA-binding activity. Antibodies to HLA class II molecules almost completely inhibited the response. These results indicate that HLA class II molecules are directly involved in the acquisition of these activities in HUVEC. [ABSTRACT FROM AUTHOR]

We have isolated tumour-infiltrating lymphocytes (TIL) clones from a patient with renal cell cancer. The cloning frequency and the effector function were measured. No difference in cloning frequency (r2 = 0.97, frequency =1:13) was observed between TIL expanded with allogeneic versus autologous feeder cells. Sixty-four clones expanded with autologous feeder cells and 37 clones expanded with allogeneic feeder cells were assayed for cytolytic activity on an autologous primary renal cell carcinoma (RCC) culture, an allogeneic RCC line, and on the K562 and Daudi cell lines. Most of these clones were also phenotyped. Although TIL clones expressing cytotoxic activity for RCC tines could be generated with both feeder cell preparations, none of the clones tested showed specificity for ceils from autologous primary RCC cultures. However, in the presence of relevant bispecific MoAbs (αOC/TR) all CD8+ TIL clones tested could be induced to lyse autologous RCC cultures. Furthermore, the cytolytic activity of all CD8+ clones tested against allogeneic RCC lines could be induced or further enhanced by αOC/TR or CD3/G250 bispecific MoAbs. In contrast, none of the CD4+ clones tested showed lytic activity. Quantitatively the cytotoxic response in the presence of αOC/TR or CD3/G250 of CD8+ TIL clones against G250+ and Mov18+ cell tines appears to be associated with the level of antigen expression on the target cells. Our results suggest that: (i) expansion of TIL with allogeneic or autotogous feeder cells does not effect the lytic profile of the clones; (ii) the use of bispecific MoAbs may overcome a lack of specificity of cytotoxic T lymphocytes. [ABSTRACT FROM AUTHOR]

Human bronchoalveolar macrophages from normal individuals function poorly as accessory cells for the presentation of common recall antigens. In sarcoidosis, alveolar macrophages (AM) are reported to be effective accessory cells for the presentation of such antigens. In this study normal and sarcoid AM were compared with blood monocytes for their ability to act as accessory cells in presenting tuberculin purified protein derivative (PPD) and streptokinase-streptodornase (SKSD) to autologous T lymphocytes, or to form spontaneous, antigen- or mitogen-induced clusters with the T cells. When compared to autologous monocytes, normal AM failed to present the two recall antigens effectively. Likewise normal AM formed very few clusters with T lymphocytes when compared to monocytes, even in the presence of antigens or the mitogen phytohaemagglutinin (PHA). In contrast, sarcoid AM presented both antigens as effectively, and were equally effective as monocytes in forming clusters with T lymphocytes, spontaneously and in further response to antigen or mitogen. The results suggest that in sarcoidosis enhanced accessory cell function and enhanced cluster formation may be related features of bronchoalveolar macrophage populations. [ABSTRACT FROM AUTHOR]

Expression of CD4 or CD8 on the cell surface is an important guide for discriminating the immunological functions of T cells. However, a minor T cell subset, which lacks both CD4 and CD8 molecules but bears the usual form of T cell receptor (TCR) αβ (CD4-CD8-TCRαβ + T cells), has recently been found not only in mice but also in humans, and its role in immune response is now of considerable interest. In order to clarify the characteristics of this newly defined T cell subpopulation, we established five IL-2-dependent CD4-CD8-TCRαβ - T cell clones from the peripheral blood of a healthy individual, and examined their various biological functions. It was found that all clones not only helped B cells in immunoglobulin production, but also exerted major histocompatibility complex-unrestricted cytotoxicity. Although their CD3/TCR complexes were functionally competent, the cytotoxicity seemed to be mediated via unknown molecules other than the CD3/TCR complex, as evidenced by the failure of CD3 MoAb to inhibit the cytotoxic activity. Our present findings showed that CD4-CD8-TCRαβ + T cells possess potential bifunction, i,e, helper and cytotoxic activities. Their roles in the pathogenesis of immunodeficiency are discussed. [ABSTRACT FROM AUTHOR]

We have previously shown that CD4+ T lymphocytes accumulated at the site of allergen-induced late-phase reactions (LPR) in the skin of atopic subjects. In order to determine whether these were predominantly "memory" or 'naive' cells, monoclonal antibodies recognizing isoforms of the CD45 common leucocyte antigen and immunocytochemical methods were used to study the composition of the T cell infiltrate. Allergen-induced late-phase skin reactions were biopsied 6, 24 or 48 h after allergen challenge. Memory (CD45RO+/UCHLI+) T cells predominated and few naive (CD45RA+/Leu18+) cells were identified. Double immunofluorescence was used lo confirm that the UCHLI+ and Leu18+ cells were CD4+ T lymphocytes. The selective recruitment of memory T cells to LPR sites is consistent with the active involvement of T lymphocytes in atopic allergic inflammation. A possible alternative explanation for apparently selective recruitment is the differential expression of endothelial adhesion molecules on memory and naive T lymphocytes. [ABSTRACT FROM AUTHOR]

In vitro studies shows that recombinant tumour necrosis factor (TNF) α and β, and interferon-gamma (IFN-γ) can enhance HIV replication, and peripheral blood mononuclear cells (PBMC) infected with HIV in vitro secrete high levels of the same cytokines. As T cells secrete all three mediators, the capacity of T cell activation signals to trigger cytokine production in PBMC from HIV-infected individuals was investigated as such patients may be immunocompromised. We demonstrate that asymptomatic seropositives in CDC group II/III as well as patients who have progressed to CDC group IV of the disease proliferate efficiently to anti-CD3 antibody, recombinant interleukin-2 (rIL-2), phytohaemagglutinin (PHA), PHA plus phorbol 12, 13 dibutyrate (PMA) but secrete significantly (P < 0.05) higher amounts of TNF-α, TNF-β and IFN-γ compared with controls in response to the same stimulants. We also show a difference between group II/III and group IV patients with the latter secreting more TNF-α and IFN-γ. The kinetics of TNF-α and -β, and IFN-γ production was stimulus dependent with overall levels varying in time for each stimulus. Furthermore, the kinetics of the response to all three stimulants were altered in seropositives; CDC group II/III and group IV patients secreted higher levels of cytokines over several time points compared to controls. The altered production of these mediators by HIV-infected patients may contribute to disease progression and to the pathogenesis of AIDS. [ABSTRACT FROM AUTHOR]

Neonatal B cells have been considered immature because of their impaired capacity to produce immunoglobulins in response to polyclonal activators in vitro. Here we demonstrate (hat cord blood mononuclear cells (MNC) produce normal levels of IgE in vitro when cultured in the presence of interleukin-4 (IL-4), indicating that the B cells are mature in their capacity to switch lo IgE-producing cells. However, in contrast to adult peripheral blood T cells, cord blood T cells failed to produce detectable levels of IL-4 upon activation by phytohaemagglutinin (PHA) concanavalin A (Con A) or combinations of PHA and the phorbol ester TPA. Interferon-gamma (IFN-γ) production by cord blood T cells following activation by Con A or PHA was also strongly reduced. However, high levels of IFN-γ, significantly higher than those produced by adult T cells, were synthesized in response to combinations of PHA and TPA, indicating that IFN-γ production by cord blood T cells is not intrinsically defective. In contrast, cord blood T cells produced levels of IL-2 that were significantly higher than those obtained by adult T cells tested in parallel. Collectively, our data indicate that the minimal levels of IgE production measured in cord blood (< 1 U/ml) are not due to immaturity of the cord blood B cells, but may be associated with the failure of cord blood T cells to produce detectable levels of IL-4, which has been shown to be responsible for induction of IgE synthesis both in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Children living in hyperendemic malarious regions have high immunoglobulin levels and an increased frequency of Burkitt's lymphoma. In a study of Gambian children which endeavours to explain these findings we showed that acute P. falciparum malaria caused spontaneous activation and growth of their B lymphocytes in vitro. A high proportion of these cells contained Epstein Barr nuclear antigen (EBNA). In ancillary experiments aimed at explaining these findings. CD4 helper cells from adult donors were destroyed with monoclonal antibody and complement. This manoeuvre resulted in loss of cytotoxic T cell control of their B lymphocytes when infected with Epstein Barr virus (EBV). In children with acute malaria., both spontaneous immunoglobulin and antibody production by B cells was increased yet CD4 helper cell control over these cells, as measured by responses to pokeweed mitogen, was found to be intact. Spontaneous and concanavalin A-driven lymphocyte proliferation was depressed. We infer from these findings that in patients with P. falciparum malaria loss of cytotoxic T cell control of the EBV in B cells, possibly due to destruction or dysfunction of a subset of CD4 cells responsible for induction ot suppressor/cytotoxic CD8 cells, leads to activation and proliferation of foci of B cells containing EBV. The expanded pool and rapid turnover of these cells may increase chances of malignant transformation leading to the genesis of Burkitt's tumor. Partial loss of suppressor mechanisms coupled with normal CD4 helper/inducer activity may result in high serum levels of immunoglobulin which are characteristic of persons living in malarious regions. [ABSTRACT FROM AUTHOR]

Several studies in the past 10 years have demonstrated the occurrence of autoantibodies against cytoplasmic constituents in patients with vasculitis and glomerulonephritis. In this review the nomenclature of these antibodies is discussed and assays and clinical associations are summarized. Although the antigens involved are not completely identified, antibodies and T cells reactive with myeloid lysozomal enzymes may both play a significant role in pathogenesis. [ABSTRACT FROM AUTHOR]

When Meth-A fibrosarcoma-bearing BALB/c mice were injected subcutaneously with 10 µg of recombinant human interleukin 2 (rIL-2) once a day for 10 days, tumour growth inhibition was in the range of 22-31% of that of the control animals. Anti-tumour effector cells against Meth-A were detected in the spleen cells of the tumour-bearing BALB/c mice injected with rIL-2, using a modified Winn-type neutralization assay with the auxiliary injection of rIL-2. To induce the strongest anti-tumour activity in this assay system, the following were necessary: 1) the effector cells were derived from tumour-bearing BALB/c mice; 2) the donors of the effector cells were injected with rIL-2:3) the recipient mice in the Winn assay were auxiliarily injected with rIL-2 (a modified Winn assay). The anti-tumour effector activity detected in the modified Winn assay was inhibited by treatment with anti-CD8 or anti-asialo GM1 antibodies plus complement (C), but not completely. We supposed that at least two kinds of anti-Meth-A effector cells with different surface antigens, positive for CD8 and asiato GM1 antigens, were induced in the Meth-A-bearing BALB/c mice injected with rIL-2; these populations seemed to function independently and at least partly as anti-tumour effector cells in this tumour-host system. These spleen cells showed in vitro cytoloxicity against Meth-A cells, which are resistant to NK cells, if the activity was measured inn 24 h 51Cr-release assay in the presence of rIL-2. [ABSTRACT FROM AUTHOR]

We tested the capacity of three rat monoclonal antibodies (MoAb), recognizing different epitopes on the L chain of mouse interleukin-2 receptor (IL-2R), to block delayed-type hypersensitivity (DTH) and local graft-versus-host reaction (GVHR). Furthermore, we investigated the effect of IL-2R- targeted immunotherapy on serum soluble IL-2R levels by ELISA technique. Following administration of AMT- 13 MoAb, in sufficient amounts to suppress both DTH (60-90% inhibition) and local GVHR (55-70% inhibition), an increase in soluble IL-2R levels up to 12-fold was observed. In contrast, the administration of 7D4 MoAb did not show any immunosuppressive effect in vivo and even decreased the soluble IL-2R levels. The third anti-IL-2R MoAb AMT45-20 had an intermediate effect. AMT4S-20 MoAb marginally suppressed the DTH as well as local GVHR (15-35% inhibition) and induced only a slight increase in soluble IL-2R levels (up to 4-fold). Both cyclosporin A, a conventional immunosuppressive drug, and the anti-L3T4 MoAb, which defines the entire T helper cell subset, suppressed GVH and DTH response but did not increase the soluble IL-2R serum levels. The increased concentration of soluble IL-2R in the serum of successfully treated mice may be due to destruction of IL-2R-positive cells by anti-IL-2R-targeted immunotherapy and seems to be a sensitive indicator for the success of such a therapy. [ABSTRACT FROM AUTHOR]

The effect of interleukin 2 (IL-2) on cord blood mononuclear cells (CBMC) was studied, with special reference to B cell function. The study shows that CBMCs proliferate in response to recombinant interleukin 2 (rIL-2) without in-vitro preactivation. The response was also detected when whole blood cultures were used. CBMCs not preactivated in vitro proliferated in response to rIL-2 even after T cell and monocyte depletion. Thus, rIL-2 affects both non-T cells and T cells of newborns without preactivation in vitro. IL-2 receptors on unstimulated CBMCs appear to be distinct from Tac antigen, as the mean number of Tac antigen-positive cells among CBMCs was only 0.8%. Furthermore, rIL-2 inhibited PWM-induced proliferation and the response was more prominent in newborns than in adults. Thus, rIL-2 seems to cause a higher increase of suppressor cell function in CBMCs than in adult peripheral blood mononuclear cells. Neither rIL-2 nor Staphylococcus aureus Cowan 1 (SAC) stimulated any IgM synthesis, but a dose-dependent IgM synthesis was obtained by combining SAC and rIL-2. Alone, however, rIL-2 appears to be an insufficient factor to induce differentiation of SAC-activated cord blood B cells, as no IgM production in response to rIL-2 occurred in T cell and monocyte-depleted cell populations. The results of this study suggest both increased suppressor cell function and intrinsic B cell deficiency as causes of a weak humoral immune response in newborns. [ABSTRACT FROM AUTHOR]

The lineage of T-lymphocyte colony-forming cells (T-CFC) and the phenotype of the progeny of T-CFC have not yet been well-defined. To characterize the progenitor cells and progeny of the T-CFC, we separated normal human peripheral blood lymphocytes into enriched lymphocyte subpopulations, stimulated with various mitogens and cultured in a semisolid agar system. After 5 days, the number of colonies was counted, and the presence of CD4+ and CD8+ cells was determined in situ with FITC-conjugated monoclonal antibodies. Plating of B cells provided the lowest, T cells an intermediate and null cells the highest number of T-cell colonies (P < 0.05). CD4+ and CD8+ cells produced equivalent numbers of T-cell colonies. T-cell colonies consisted of either CD4+ or CD8+ cells; mixed-cell colonies were rarely present. Plating of CD4+ or CD8+ cells produced both CD4+ and CD8+ colonies. We conclude that T-CFC exist in the CD4+, CD8+ and null-cell populations. In addition, T-CFC give rise to T-cell colonies possessing either CD4+ or CD8+ determinants. [ABSTRACT FROM AUTHOR]

T cell-derived helper factors can cause activated B cells to proliferate and differentiate into immunoglobulin (Ig)-secreting cells. In the pokeweed mitogen (PWM)-driven Ig production system, the cell-cell interaction necessary for the production of the helper factors was analysed. T cells were pulsed with PWM with or without autologous monocytes. The T cells were then isolated, and incubated for 48 h. Supernatants were tested for their ability to promote differentiation of activated B cells. We found that cell-cell contact between T cells and monocytes for the first 3 h of culture is required to produce the T cell-derived helper factors upon stimulation with PWM. We next examined which T cell subsets are involved in the production of helper factors and which surface molecules either on T cells or on monocytes are responsible for the cell-cell interaction to produce helper factors. A series of monoclonal antibodies were added to T cell subsets with monocytes during the PWM-pulsed period. Although T4+ and T8+ cells could produce almost equal amounts of helper factor activity upon PWM-stimulation, the interactions between T3 and T4 antigens on T4+ cells and Ia-like antigens on monocytes and those between T3 and T8 antigens on T8+ cells and HLA class I antigens on monocytes are respectively essential for the production of T4+ cell-derived and T8+ cell derived helper factors. [ABSTRACT FROM AUTHOR]

We studied natural killer (NK) cell activity and numbers in the peripheral blood obtained from patients with Behcet's disease (BD) in inactive and convalescent stage, and from healthy controls. Ratios of helper/Suppressor cells (OKT4/OKT8) were below 1-0 in patients with active stage and were normal in the convalescent stage of BD. A relative increase of OKT8+ cells and at the same time of Leu 7+ cells was obtained in the active and convalescent BD stages. Double marker analysis revealed that the sub-population of cells expressing both the T8+ and the Leu 7+ antigen (T8+/Leu 7+) was increased in patients with active stage, and normal in the convalescent stage. The frequency of cells reactive with Leu 11 monoclonal antibody (active NK cells) was evaluated in patients with BD, Data from peripheral blood showed an increased sub-population of T8+/Leu 7+ double marker cells, and a decreased Leu 11+ cell sub-population in patients with active BD. but the majority of Leu 7+ cells in patients with convalescent stage lacked OKT8 antigen when investigated in a double marker system. A parallel increase of Leu 11+ cells was observed in the convalescent stage. This phenotypic analysis was carried out with the NK in vitro functional evaluation of cell populations from peripheral blood. NK cell activity in the clinically active stage of BD was significantly lower than that of healthy controls and patients in the convalescent stage. The decrease of peripheral blood NK function in patients with active BD may be related to the presence of immature forms of NK cells and/or to the increased percentage of T8+/Leu 7+ cells. [ABSTRACT FROM AUTHOR]

Rabbit antisera raised against eight monoclonal antibodies (MoAb) binding to distinct mycobacterial antigens revealed individual anti-idiotype specificities following cross-absorption with normal mouse globulin. Only one of these antibodies (Rb71), directed towards an M. tuberculosis-specific epitope on the 38 kD protein antigen was able to stimulate mouse T cell responses which had 'internal image' characteristics. This was demonstrated by anti-Id induced in vitro proliferation of Lyt 1.2+ T cells and the elicitation of delayed type hypersensitivity (DTH) foot pad reactions in antigen stimulated BALB/c mice. The DTH reaction was equally strong in mice sensitized with either M. tuberculosis or M. bovis soluble extracts, thus showing a greater degree of cross-reactivity than antibody binding of the corresponding TB7I MoAb. The immunizing potency of the anti-Id in vivo was demonstrable in three strains of mice following injection of Rb71 emulsified with incomplete Freund's adjuvant. These mice showed 38 kD antigen induced DTH-reactions as well as in vitro proliferation of spleen cells. The display of T cell stimulatory internal image by anti-Id may be interpreted as a consequence of binding specificity of TB71 MoAb of a T cell epitope present in the 38 kD antigen. [ABSTRACT FROM AUTHOR]

Cell samples derived from the thyroid glands of twelve children with juvenile autoimmune thyroiditis (JAIT) were analysed. The cytological findings were those of chronic lymphocytic thyroiditis in eight and suggestive of that disease in four patients. About 86% of the cells infiltrating the thyroid were lymphocytes, 4% were lymphoid blasts, 6% neutrophils and 3% monocytes. Analysis using monoclonal antibodies showed that about 60% of the lymphocytes were T cells and half of the lymphocytes expressed HLA Class II-antigens, T helper cells dominated with a T helper/suppressor ratio of 2-2 in thyroid while the ratio was 12 in peripheral blood, of the thyroid epithelial cells, 80% also expressed HLA class II, The immune activation and immunoglobulin synthesis within the thyroid are discussed. [ABSTRACT FROM AUTHOR]

During autologous mixed lymphocyte reaction (AMLR) both helper and suppressor T cells capable of regulating B cell responses are generated. The proliferative response of T cells as well as the generation of T suppressor cells in the AMLR of patients with active systemic lupus erythematosus (SLE) is diminished. In contrast, the T helper cells generated in the AMLR show a hyperactivity. The diminished HLA-class II antigen expression observed on non-T cells of SLE origin was restored by treatment of the cells with gamma-interferon (γ-IFN). When tested by immunoglobulin secretion, γ-IFN enhanced T helper cell activity but failed to affect T cell proliferation and T suppressor cell generation in the AMLR derived from patients with SLE. Human recombinant interleukin 2 restores both the proliferative response of T cells and the induction of T suppressor cells in AMLR. [ABSTRACT FROM AUTHOR]

In the burn patient, the mechanisms leading to impaired T lymphocyte activity are unclear. The capacity for T cell proliferation and the expression of Tac antigen (IL-2 receptor) was assessed during the post-burn period in patients with injuries ranging from 5-68%, total body surface area. T cell-dependent (polyclonal) immunoglobulin synthesis, mixed lymphocyte reaction and Interleukin-2 production were also determined in these patients and correlated with survival. Surviving patients demonstrated a transient reduction while terminal patients exhibited a permanent reduction in the number of Tac lymphocytes, unrelated to the absolute number of T cells, during the post-burn period. The reduced percentage of lL-2 receptor-expressing T cells coincided with the suppressed antibody response and reduced alloreactivity. Although the concentration of IL -2 was decreased in all patients throughout the hospitalization period, surviving patients showed a gradual increase in its production while terminal patients gradually decreased to undetectable levels. Exogenous recombinant IL-2 induced a significant enhancement of in-vitro polyclonal immunoglobulin production and blastogenesis in the mixed lymphocyte reaction in immunosuppressed patients who demonstrated up to 50%, reduction in the percentage of IL-2 receptor positive cells. Thus, the reduced capacity for production of and response to lL-2 alter thermal injury may lead to the immunosuppression due to a lack of T lymphocyte clonal expansion. The permanent nature of this detect in patients who died from fatal sepsis may suggest a causative relationship. [ABSTRACT FROM AUTHOR]

We studied mitogen- and antigen-induced interleukin 2 (IL-2) production in HTLV-Ill LAV infected and non-infected individuals and compared the results with T cell subpopulations. and with mitogen- and antigen-induced DNA synthesis and production of leucocyte migration inhibitory factor (LIF in order to understand the controversial findings related to IL-2 production in HTLV-III/V infection. The HTLV-llI/LAV antibody positive group showed immunologial defects: low T helper (Th) cells, high Th- suppressor (Th) cells, reduced mitogen- and antigen-induced DNA-synthesis. but LIE production comparable to the HTLV-lll/LAV antibody negative group. The total amount of IL-2, produced either as a response to a mitogenic stimulus or as a response to a soluble antigenic (purified protein derivative of tuberculin, PPD) stimulus, was lower in the HTLV-III/LAV antibody positive group. However, adjusting the IL-2 production to the amount of Th-cells showed that the IL-2 produced by a standard number of Th-cells after mitogen induction was similar in HTLV-lll/LAV infected and non-infected individuals. In contrast, the ability of Th-cells of infected persons to produce IL-I or to proliferate as a response to a soluble antigenic stimulus, was considerably diminished. We conclude that HTLV-lll infection leads to a selective incapability to mount a specific Th- cell response either due to an intrinsic defect in the Th-cell population or due to metabolic and/or functional disturbances in antigen-processing and presenting accessory cells. [ABSTRACT FROM AUTHOR]

In vitro monoclonal immunoglobulin (mIg) production of cultured tumour cells- prepared from the bone marrow (BM) or from the peripheral blood (PB) of 40 multiple myeloma (MM) patients, 16 patients with monoclonal gammopathy of undetermined significance and two patients with M. Waldenström- was measured with an enzyme-linked immunosorbent assay (ELISA) using anti-idiotype and anti-class specific antisera, After in vitro stimulation with pokeweed mitogen (PWM) or OKT3 antibody, mIg production was regularly suppressed in BM cell cultures, whereas enhanced, unaltered or suppressed production was observed in PB cell cultures. These observations show that the expanded clone in MM can still be regulated in vitro. Separation experiments demonstrated the involvement of CT cells in this in vitro system. The results could be explained by the hypothesis that activated T cells can suppress mature cells of B cell differentiation, as found in BM of the patients, but stimulate earlier B cells from the peripheral blood towards differentiation into Ig secreting cells. [ABSTRACT FROM AUTHOR]

CBA/Ca mice were infected by either the intravenous or intraperitoneal route with Mycobacterium microti and the subsequent changes in local macrophage populations examined. Following infection, the number of macrophages increased and they showed greater expression of both MHC Class II molecules. This response was not dependent on viability of the mycobacteria, in contrast to reports with other microorganisms such as Listeria. Studies in sublethally irradiated mice indicated that persistent antigen could give rise to a response after a period of host recovery which was radiation dose dependent. This procedure also highlighted differences in the regulation of different murine class II antigens in vivo as seen by delayed re-expression of I-E antigens. Macrophage accessory cell function, as assessed by an in vitro T cell proliferation assay, correlated with la expression after fixation, but not after indomethacin treatment; this highlights the diverse nature of regulatory molecules produced by these cells. [ABSTRACT FROM AUTHOR]

Thirty-two adult patients with minimal change nephritic syndrome (MCNS) were studied in order to clarify the characteristics of the immune system in MCNS and their relation to clinical activity. In the active phase (n = 17), serum immunoglobulin (Ig) M and E levels, B lymphocytes (surface Ig-positive cells) and their subsets, surface IgG, IgM and IgE positive cells; Bγ, Bμ and B∊, were increased, whereas the serum IgG level and OKT3-reactive cells, peripheral T lymphocytes; T3, were decreased. In the remitted phase maintained by steroid therapy (n = 17), serum Igs and and B lymphocytes subsets tended to return to normal levels concomitant with decreases in T3 and T4, and an increase in T8 in consequence of a marked decrease in T4/T8 (helper/suppressor) ratio. In stable remission continuing with no steroid therapy (n = 14), the above abnormalities returned to normal ranges, except for serum IgM which remained at a high level and re-elevated serum IgE. These results suggest that immunological abnormalities in MCNS are characterized by acceleration of the IgE and IgM producing systems and impaired maturation of the IgG producing system despite normal differentiation from the IgM producing to IgG producing system, possibly caused by T lymphocyte dysfunction. [ABSTRACT FROM AUTHOR]

Addition of 40 μM 2'deoxyguanosine (2'd Guo) results in enhancement of human lymphocyte cultures stimulated with pokeweed mitogen. assessed by staining intracytoplasmic immunoglobulins. Furthermore, B cell responses were enhanced under experimental conditions favouring T cell suppression rather than help. Experiments with enriched B cell fractions indicate that 2'dGuo does not directly stimulate B cell responses. The enhancement by 2'dGuo was still observed in the presence of irradiated (non-proliferating) T cells. The mechanism of enhancement by 2'dGuo is discussed in terms of its effect on proliferation-independent suppressor T cells. [ABSTRACT FROM AUTHOR]

Human T lymphocyte colonies may be grown in agar from pre-T peripheral blood cells. Pre-T cells giving rise to these colonies represent 0.5%, of the non-adherent. E rosette and Leu 1 depleted mononuclear cell subpopulation. T colony formation is induced by PHA stimulation and only if media conditioned by PHA stimulated peripheral blood lymphocytes (PHA-LCM) is added. These media contained interleukin-2 (IL-2) and T colony promoting activity (TCPA) for pre-T cells. TCPA is co-eluted with IL-2 by gel filtration with an apparent molecular weight of 18,000 daltons. Moreover, when PHA-LCM are absorbed on IL-2-dependent cultured T cells, TCPA is removed as well as IL-2. In attempt to further demonstrate the role of IL-2 in T colony formation by the pre-T cells we used the anti-Tac monoclonal antibody directed against IL-2 receptor. We demonstrated that anti-Tac inhibits T colony formation in a dose-dependent manner in pre-T cells. We conclude that IL-2 is the essential exogenous factor contained in PHA-LCM which allows pre-T cell differentiation expression and proliferation in agar medium. [ABSTRACT FROM AUTHOR]

The histochemical demonstration of acid phosphatase (ACP) and adenosine triphosphatase (ATP) has been combined with standard immunofluorescence techniques, using a panel of monoclonal and conventional antibodies, to examine lymphocyte and macrophage subsets and their microanatomical relationships within the subcutaneous rheumatoid nodule (RN). This analysis reveals that the RN is composed largely of strongly HLA-DR+. ATP- macrophages which contain lysosomal enzymes (ACP) in large amounts. The lymphocytic infiltrate which is sparse and poorly organized is comprised almost entirely of thymus derived lymphocytes (T cells) with a normal proportion of helper/inducer (0KT4+) and suppressor/cytotoxic (OKT8+) cells. These observations are in contrast to the findings in the rheumatoid synovial membrane of a prevalence of interdigitating type, HLA-DR+ cells and the predominance of helper (OKT4+) type T cells. [ABSTRACT FROM AUTHOR]

Various immunological parameters were investigated in patients with Hashimoto's thyroiditis (HT) and Graves' disease (GD). The total T cell numbers were significantly decreased in both diseases whether they were enumerated by E rosetting or by pan-T cell monoclonal antibodies (OKT3 and anti-Leu 1). This diminution was due to a loss in the inducer T cell subset (OKT4 + /Leu 3a+) whereas the cytotoxic/suppressor T cells (OKT8 +/Leu 2a+) were present at normal levels in both diseases. The B cells were significantly higher in GD patients than in controls but were not modified in HT patients. Monocyte percentages remained unchanged and DR+ cells were slightly increased in the two diseases. On the other hand, T lymphocyte responses to stimulation by autologous or allogeneic cells were significantly impaired in GD but not in HT whether cultures were performed in autologous plasma or AB serum. In addition, lymphocytes from normal subjects were unable to proliferate in auto- or allo-MLR in the presence of plasma from GD patients but they were reactive in the presence of HT plasma or AB serum. Taken together, these results suggest that the patients with autoimmune thyroid disorders exhibit a T cell imbalance within the OKT4+/Leu 3a+ subset. Moreover, this abnormality is correlated with the observation that autoreactive and alloreactive cells are defective in GD. [ABSTRACT FROM AUTHOR]