Effects of the lpr/lpr mutation on T and B cell populations in the lamina propria of the small intestine, a mucosal effector site.

MRL mice, which develop a lymphoproliferative disease characterized by increased numbers of alpha/beta T cell receptor+ (TCR+) B220/6B2+CD4-CD8- T cells [lymphoproliferation (lpr) T cells], were studied for the effect of the lpr/lpr mutation on the mucosal immune system in the gastrointestinal (GI) tract. We analyzed the effect of the lpr gene mutation on T and B cell populations in the Peyer's patches (PP) and the lamina propria lymphocytes (LPLs), as examples of major IgA inductive and effector tissues in the GI tract respectively. Normal mouse PP contain B cells committed to IgA (surface IgA+) but only low numbers of B cells producing IgA. However, enhanced spontaneous IgA and IgG synthesis occurs in the PP of MRL mice. Further, we have now shown that PP of MRL mice are populated by lpr T cells. Interestingly, lpr T cells were not present in significant numbers in LPLs of MRL mice, even in older animals. Of interest was the finding that the ratio of CD4+ to CD8+ T cells in the lamina propria was lower in MRL when compared with control mice, and the CD8+ T cell subset actually predominates in LPLs of autoimmune mice. In addition, the number of gamma/delta TCR+ T cells in LPL of MRL lpr/lpr mice was significantly increased, especially in MRL lpr/lpr mice at 6 and 12 weeks of age. When the isotype distribution of B cells in LPLs was analyzed, no changes were noted in MRL lpr/lpr mice in comparison with MRL +/+ or normal control mice, and the pattern was IgA much greater than IgM greater than IgG. These results show that although increased numbers of CD8+ T cells and gamma/delta TCR+ cells occur in the LPLs of MRL mice, a normal distribution of plasma cell isotypes (IgA much greater than IgM greater than IgG) is found in this mucosal compartment. Further, Ipr T cells do not develop in the lamina propria compartment of the GI tract.     

Intestinal intraepithelial lymphocyte T cells are resistant to lpr gene-induced T cell abnormalities.

The mucosal immune system of the gastrointestinal (GI) tract consists of Peyer's patches (PP), which are IgA inductive sites, and more diffuse effector regions which include cells in the intraepithelial lymphocyte (IEL) compartment. Since autoimmune MRL lpr/lpr (MRL/lpr) mice develop a proliferating CD3+, CD4-, CD8- (double negative; DN), B220+ T cell subset in systemic lymphoid tissue, we have initiated studies to determine the distribution of CD3+, DN, B220+ T cells (B220+ T cells or lpr/lpr T cells) in the GI immune system. Specifically, we examined T cell subsets separated according to expression of CD4, CD8, Thy-1, B220, alpha/beta T cell receptor (TcR) and gamma/delta TcR in PP and IEL of MRL/lpr mice at 6, 12 and 21 weeks of age. Increased numbers of CD3+ T cells were noted in both PP and spleen of 12- and 21-week-old mice in which the development of autoimmune disorders were also evident. However, normal numbers of CD3+ IEL T cells were seen in MRL/lpr mice in all three age groups tested. When the presence of T cell lymphadenopathy was examined in both IgA inductive and effector tissues, the PP followed the B220+ T cell pattern seen in the spleen, where approximately 30%-50% of CD3+ T cells in the PP of 12- and 21-week-old MRL/lpr mice expressed the phenotype of lpr/lpr T cells and greater than 90% were alpha/beta TcR+. On the other hand, B220+ T cells had not developed in PP or spleen of 6-week-old MRL/lpr mice. Of interest was the finding that IEL from lpr/lpr homozygous mice did not contain B220+ T cells in any age group tested. In this regard, the IEL of MRL/lpr mice comprised an identical pattern and frequency of CD4-/CD8+, CD4+/CD8-, DN and CD4+/CD8+ (double positive, DP) T cell subsets as their normal counterparts (i.e. MRL +/+, BALB/c and C3H/HeN mice) which consisted of approximately 75%, approximately 7.5%, approximately 7.5% and approximately 10%, respectively. Further, Thy-1, gamma/delta TcR and alpha/beta TcR expression in these four subsets of MRL/lpr IEL were very similar to normal mice. These results suggest that the intestinal IEL compartment is minimally affected by the lpr/lpr mutation which induces T cell abnormalities and indicate that B220+ T cells do not preferentially home to IEL. Further, our results support the concept that IEL T cells develop as a separate T cell lineage from thymus-derived cells.     

Effects of purified anti-Lyt-2 mAb treatment on murine listeriosis: comparative roles of Lyt-2+ and L3T4+ cells in resistance to primary and secondary infection, delayed-type hypersensitivity and adoptive transfer of resistance.

Mice treated with purified anti-Lyt-2 monoclonal antibody (mAb) displayed a delayed ability to eliminate a primary Listeria monocytogenes infection from their spleens. Elimination of listeriae from the liver was unimpaired by anti-Lyt-2 mAb treatment. Treatment with anti-L3T4 mAb, alone or in combination with anti-Lyt-2 mAb, resulted in similar increases in the numbers of listeriae recovered from the spleens at 7 days after challenge. Listeria-infected mice that had been treated with anti-Lyt-2 mAb alone developed a strong delayed-type hypersensitivity (DTH) response, although it was significantly reduced as compared to control listeria-infected mice. In contrast, treatment with anti-L3T4 mAb severely impaired the development of DTH in listeria-infected mice. Treatment with anti-Lyt-2 mAb and anti-L3T4 mAb, singly or in combination, did not prevent mice from developing increased anti-listeria resistance if they were then immunized with a sublethal dose of L. monocytogenes. Treatment of mice with anti-Lyt-2 mAb or anti-L3T4 mAb before immunization, however, reduced the ability of their spleen cells to transfer anti-listeria resistance to recipient mice. These results indicate that Lyt-2+ cells make substantial contributions to the resistance of mice to primary L. monocytogenes infection, and to the ability of spleen cells from listeria-immunized mice to transfer resistance to naive recipients.     

Generation of L3T4-/Ly-2- T cells in Peyer's patches of mice treated with monoclonal antibody against helper T cells

The effect of in vivo administration of anti-L3T4 monoclonal antibody on the generation of an L3T4-/Ly-2- (CD4-/CD8-) population of Thy-1.2+ cells was examined in Peyer's patches of mice by two-color flow cytometry. Female BALB/c mice aged 8 wk were given 4-6 weekly injections of either anti-L3T4 (1 mg/wk) or phosphate-buffered saline (control group), and dispersed Peyer's patch cells analyzed for the presence and absence of L3T4 and Ly-2 on Thy-1.2+ cells. In anti-L3T4 treated mice, L3T4-/Ly-2- T cells accounted for 25-30% of the Thy-1.2+ cells, whereas in control mice these cells represented only 3-4% of the T cells. The remaining 70-75% of the Thy-1.2+ cells after anti-L3T4 treatment were Ly-2+ and not L3T4+. The L3T4-/Ly-2- population of Thy-1.2+ cells is a novel subset which has not been previously found in Peyer's patches and is amplified when helper T cells are depleted.     

T-cell receptor V beta repertoire of L3T4+ regulatory T cells in anti-L3T4 antibody-induced tolerant NOD mice.

In ongoing studies, we have found that short-term administration of anti-L3T4 monoclonal antibodies (mAb) prevents the development of overt diabetes in non-obese diabetic (NOD) mice. In the present work, we asked whether L3T4+ T cells or Lyt-2+ T cells can suppress the diabetes in these mice. L3T4+ T cells or Lyt-2+ T cells were sorted using a magnetic cell sorter, then were transferred into cyclophosphamide-induced male NOD mice. We obtained evidence that the L3T4+ but not Lyt-2+ T cells did inhibit the diabetes, thereby indicating that the former can regulate diabetes in anti-L3T4 mAb-induced tolerant NOD mice. Further analysis on T-cell receptor (TCR) V beta genes on splenic T cells from anti-L3T4 mAb-treated NOD mice revealed that V beta 4-positive T cells expanded predominantly, while L3T4+ T cells represented heterogeneity of the TCR V beta gene, hence, V beta 4-positive Lyt-2+ T cells generate predominantly. Our findings suggest that both L3T4+ and Lyt-2+ T cells renew and function as regulatory cells, through clonotypic interaction in tolerant NOD mice.     

The in vivo depletion of CD4+ T cells prevents antigen-induced eosinophil infiltration into mouse skin.

In order to determine the role of CD4+ T cells and CD8+ T cells in causing antigen-induced eosinophil infiltration into the site of late-phase reaction (LPR), we examined the effect of the in vivo depletion of CD4+ T cells and CD8+ T cells on antigen-induced eosinophil infiltration into mouse skin. Eosinophil infiltration into the skin of ovalbumin (OA)-sensitized BALB/c mice was biphasic after subcutaneous OA challenge, reaching the first peak at 6 h and the second peak at 24 to 48 h. The in vivo depletion of CD4+ T cells by pretreatment with anti-L3T4 monoclonal antibody (mAb) significantly decreased the second peak (at 24 h and 48 h), but not the first peak (at 6 h), of OA-induced eosinophil infiltration into the skin of OA-sensitized mice. However, the depletion of CD8+ T cells by pretreatment with anti-Lyt-2 mAb had no significant effect on either the first or second peak of OA-induced cutaneous eosinophilia in the mouse. These results indicate that CD4+ T cells, but not CD8+ T cells, play an important role in causing antigen-induced eosinophil recruitment of cutaneous LPR.     

Protection against Chlamydia psittaci in mice conferred by Lyt-2+ T cells.

A murine model was used to study the respective roles of L3T4+ and Lyt-2+ T cells in protection against Chlamydia psittaci. Donor mice were intravenously (i.v.) infected with 1 x 10(5) plaque-forming units (PFU) per mice of live C. psittaci. One month after inoculation, splenic cells from donors were transferred into syngenic recipients (5 x 10(7) cells/mouse). As measured by splenic colonization on Day 6 after i.v. challenge (1 x 10(5) PFU/mouse), transfer with primed (untreated) cells conferred a 3 log protection in this model. In vitro treatment, before transfer, of splenic cells with anti-Lyt-2 monoclonal antibody (mAb) and complement, markedly impaired the protection in comparison with control mice transferred with primed untreated cells, whereas treatment with anti-L3T4 mAb did not reduce the transferred protection. Resistance to a reinfection with C. psittaci was also studied after selective in vivo depletion of L3T4+ and Lyt-2+ T cells. One month after primary infection, mice were treated with anti-L3T4 or anti-Lyt-2 mAb and challenged thereafter (i.v., 1 x 10(5) PFU). The splenic colonization on Day 6 after challenge demonstrated that treatment with anti-Lyt-2 mAb impaired resistance against a subsequent infection with C. psittaci. Treatment with anti-L3T4 mAb in vivo had no effect on protection, as previously described in vitro. The mechanisms by which Lyt-2+ T cells could participate in the elimination of bacteria were discussed.     

CD4-/CD8-T cells: amplification in spleens of mice following in vivo treatment with monoclonal antibody anti-L3T4

Amplification of L3T4-/Ly-2-(CD 4-/CD 8-) T cells following in vivo administration of anti-L3T4 monoclonal antibody was examined in the spleen of mice by flow cytometry and immunohistochemistry. BALB/c mice were given 4-7 weekly injections of either anti-L3T4 (1 mg/week) or phosphate-buffered saline (control group), and dispersed spleen cells and tissue sections analyzed for the presence of Thy-1.2+, L3T4+, or Ly-2+ cells, and for the absence of both L3T4 and Ly-2 on Thy-1.2+ cells. Prior to treatment, L3T4+ and Ly-2+ cells accounted for virtually all Thy-1.2+ cells in approximately a 2:1 ratio. Following anti-L3T4 treatment, L3T4+ cells were depleted, and Ly-2+ cells accounted for about 2/3 of the Thy-1.2+ cells. A population of L3T4-/Ly-2- T cells was generated that accounted for 20-30% of the Thy-1.2+ cells, accounted for most of the Thy-1.2+ cells in red pulp, and was also present among the predominant Ly-2+ cells in periarteriolar sheaths.     

CD4+T细胞在痢疾疫苗诱导小鼠肠粘膜免疫应答中的作用

以本室构建的双价痢疾候选疫苗株ＦＳ５４１６ 作为口服免疫原,检测了小鼠ＰＰ 结（Ｐｅｙｅｒ ,ｓ ｐａｔｃｈｅｓ） 中Ｔ 淋巴细胞的体外增殖反应, 观察了腹腔注射抗Ｌ３Ｔ４ ｍ Ａｂ 对小鼠肠粘膜部位产生特异性Ｉｇ 分泌细胞的影响。结果表明：①小鼠口服免疫后,ＰＰ 结中的ＣＤ４ ＋ Ｔ 细胞可产生明显的特异性增殖反应：②选择性地删除ＣＤ４ ＋ Ｔ 细胞后,小鼠肠粘膜无抗原特异性Ｉｇ 分泌细胞产生。以上提示,小鼠肠粘膜对痢疾疫苗的免疫应答需要ＣＤ４ ＋ Ｔ 细胞的参与。     

Treatment of murine lupus with monoclonal antibody to L3T4. I. Effects on the distribution and function of lymphocyte subsets and on the histopathology of autoimmune disease

Monoclonal antibodies (MoAb) to L3T4 have been used successfully to suppress autoimmunity in murine models for several human autoimmune diseases. To clarify the immunologic and clinical consequences of treatment with anti-L3T4, we examined the effects of chronic administration of anti-L3T4 on the composition of lymphoid organs, the function of lymphocytes, and the histopathology of autoimmune disease in lupus-prone NZB/NZW F1 (B/W) mice. Weekly treatment with anti-L3T4 (2 mg/mouse) from age 5 to 8 months depleted L3T4+ cells from the spleen and lymph nodes, and prevented the development of splenomegaly and lymphadenopathy. The MoAb bound to target cells in the thymus and modulated their expression of the L3T4 antigen but, in contrast to its effect in extrathymic sites, anti-L3T4 did not deplete the target population from the thymus. In fact, after 3 months of therapy, mice that had been treated with anti-L3T4 had much larger thymuses than control mice that had been treated with saline, suggesting that treatment with anti-L3T4 prevented the thymic atrophy that occurs spontaneously in murine lupus. Despite depleting L3T4+ cells from the spleen, treatment with anti-L3T4 did not diminish the response of splenic lymphocytes to T and B cell mitogens, and it augmented splenic natural killer (NK) cell activity. Finally, treatment with anti-L3T4 decreased the diverse histopathologic manifestations of murine lupus. It dramatically reduced glomerular immunoglobulin and complement deposition and diminished lymphocytic infiltration and vasculitis in the kidneys. Treatment also reduced extrarenal immunopathology, including focal hepatitis and salivary gland infiltration. These observations have implications regarding the use of CD4 MoAb in people with autoimmune diseases.     

CD4+CD8+ thymocytes develop into CD4 or CD8 single-positive cells in athymic nude mice

A differentiation pathway from CD4+CD8+ cells to CD4+CD8- or CD4-CD8+ cells was investigated in athymic nude mice. Using fluorescence-activated cell sorter, CD4+CD8+ cells were sorted out from AKR thymocytes (H-2k, Thy-1.1) stained with two monoclonal antibodies against CD4 and CD8 (anti-L3T4 and anti-Ly-2). These CD4+CD8+ AKR thymocytes were injected i.v. into CBA or C3H nude mice (H-2k, Thy-1.2) which had received 650 rads and had been reconstituted with syngeneic nude bone marrow cells. The lymph node cells of the nude recipients at 4 wks post-thymocyte transfer were shown to contain 50% AKR-derived Thy-1.1+ cells. The majority of the Thy-1.1+ cells were found to express either CD4 or CD8 alone but not to express both CD4 and CD8. These findings indicate that CD4+CD8+ thymocytes can develop into CD4+CD8- and CD4-CD8+ single-positive cells in extrathymic tissues.     

CD40 ligation releases immature dendritic cells from the control of regulatory CD4+CD25+ T cells

We report that disruption of CD154 in nonobese diabetic (NOD) mice abrogates the helper function of CD4+CD25- T cells without impairing the regulatory activity of CD4+CD25+ T cells. Whereas CD4+ T cells from NOD mice enhanced a diabetogenic CD8+ T cell response in monoclonal TCR-transgenic NOD mice, CD4+ T cells from NOD.CD154(-/-) mice actively suppressed it. Suppression was mediated by regulatory CD4+CD25+ T cells capable of inhibiting CD8+ T cell responses induced by peptide-pulsed dendritic cells (DCs), but not peptide/MHC monomers. It involved inhibition of DC maturation, did not occur in the presence of CD154+ T-helper cells, and could be inhibited by activation of DCs with LPS, CpG DNA, or an agonistic anti-CD40 mAb. Thus, in at least some genetic backgrounds, CD154-CD40 interactions and innate stimuli release immature DCs from suppression by CD4+CD25+ T cells.     

Role of CD4+ T lymphocytes and interleukin-5 in antigen-induced eosinophil recruitment into the site of cutaneous late-phase reaction in mice.

Previous studies suggested that the eosinophil recruitment into the site of cutaneous late-phase reaction (LPR) was dependent on IgE antibody and mast cells. In this study, we determined the role of CD4+ T cells and CD8+ T cells in causing antigen-induced eosinophil recruitment of LPR in mouse skin. Eosinophil infiltration into the subcutaneous tissue of ovalbumin (OVA)-sensitized BALB/c mice was biphasic, reaching the first peak at 6 h after the subcutaneous challenge with OVA and the second peak at 24 to 48 h. The in vivo depletion of CD4+ T cells by pretreatment with anti-L3T4 monoclonal antibody (mAb) significantly decreased the second peak (at 24 h and 48 h), but not the first peak (at 6 h), of OVA-induced eosinophil infiltration into the skin of OVA-sensitized mice. However, the depletion of CD8+ T cells by pretreatment with anti-Lyt-2 mAb had no significant effect on either the first peak or second peak of OVA-induced cutaneous eosinophilia. Pretreatment with anti-murine interleukin-5 (IL-5) mAb also decreased the second peak, but not the first peak, of OVA-induced cutaneous eosinophilia. In contrast to the inhibitory effects of depletion of CD4+ T cells and of anti-IL-5 mAb on the second peak of antigen-induced cutaneous eosinophilia, disodium cromoglycate and a selective antagonist for platelet activating factor (PAF) CV-6209 decreased the first peak of OVA-induced cutaneous eosinophilia in the mouse. These results indicate that CD4+ T cells, but not CD8+ T cells, cause the second peak of antigen-induced eosinophil recruitment of cutaneous LPR and that IL-5 mediates this eosinophil recruitment. In contrast, the first peak of antigen-induced eosinophil recruitment of cutaneous LPR is mediated by mast cells and PAF.     

Mediation of immunity to Eimeria vermiformis in mice by L3T4+ T cells.

Immunity to infection with Eimeria vermiformis was transferred in NIH mice by both the nylon wool-adherent (B-cell-enriched) and nonadherent (T-cell-enriched) fractions of lymphocytes (spleen and mesenteric lymph node) taken from infected donors. Transfer was more variable with the adherent fraction, and when contaminating T cells were removed by treatment with anti-Thy1 monoclonal antibody (MAb) and complement, this fraction lost all protective activity. The protective effect of T-cell-enriched populations of mesenteric lymphocytes was abrogated by treatment with anti-L3T4 MAb and complement in vitro before transfer or by opsonization with this MAb in vitro before intravenous inoculation into recipients. Similar treatments of cells with anti-Lyt2 MAb did not have this effect, confirming that Thy1+ L3T4+ cells mediate the adoptive transfer of immunity to E. vermiformis. Thy1+ L3T4+ cells were also shown to limit the replication of E. vermiformis in primary infections: mice depleted of this subset (by thymectomy followed by intravenous injection of anti-L3T4 MAb) passed greater numbers of oocysts over a longer period of time than did mice similarly depleted of Lyt2+ cells.     

Origin and selection of peripheral CD4-CD8- T cells bearing alpha/beta T cell antigen receptors in autoimmune gld mice

We have analyzed the origin and development of unusual CD4-CD8- alpha/beta T cell receptor-positive peripheral T cells produced in large numbers by mice homozygous for the gld mutation (C3H-gld/gld). These mice may be an important model for investigating processes controlling T cell development. Bone marrow transfers demonstrated that the gld defect was intrinsic to bone marrow-derived cells. Clonal deletion of potentially autoreactive cells was observed in peripheral gld CD4-CD8-, CD4+CD8-, and CD4-CD8+ T cells, as well as mature thymocytes. This suggests that gld CD4-CD8- T cells have passed through the thymus in ontogeny and that gld autoimmunity does not result from a general defect in elimination of self-reactive thymocytes. These observations, combined with demethylation of the CD8 gene in the CD4-CD8- population, support prior expression of CD4 and/or CD8 in gld CD4-CD8- T cell ontogeny, perhaps at a CD4+CD8+ stage. Steroid sensitivity of gld thymocytes and CD4-CD8- T cells was normal. Therefore, we found no gross abnormalities in two major mechanisms of inducible cell death in the gld thymus, the clonal deletion process associated with tolerance and the steroid-inducible endogenous endonuclease thought to be involved in apoptosis of unselected thymocytes. The data suggest that if gld CD4-CD8- T cells arise via escape from normal elimination in the thymus, they must do so by a novel defect in thymic selection (perhaps related to aberrant positive signals) and/or are expanded by an extrathymic process which allows clonal deletion to occur.     

T lymphocytes in rat germinal centres belong to an ER3+ subpopulation of CD4+ cells.

Two-colour immunofluorescence histochemistry showed directly that greater than 90% of CD4+ germinal centre T cells in rat spleen or lymph node examined 7 days after immunization bear the antigen recognized by the monoclonal antibody (mAb) ER3. By contrast, only 30-40% of all thoracic duct or lymph node CD4+ cells were ER3+, as determined by two-colour flow cytometry. CD8+ cells were ER3+, but nearly all B cells were ER3-. Thus, germinal centre T cells belong to a subpopulation of CD4+ cells. Because only 25-30% of CD4+ cells that lack higher molecular weight forms of CD45 (i.e. mAb MRC OX32 cells, equivalent to MRC OX22 cells) express ER3, the CD4+ subpopulations defined by ER3 are neither identical nor complementary to the subsets defined by restricted expression of CD45 epitopes.     

过氧化物酶体增殖剂激活受体α对小鼠T、B细胞发育的影响

目的研究过氧化物酶体增殖剂激活受体α(PPARα)与小鼠免疫系统功能和发育的关系。方法喂养含过氧化物酶体增殖剂(PP)的食物后,观察野生型C57Bl/6小鼠和PPARα缺陷型小鼠胸腺、脾脏的重量及胸腺细胞、脾细胞数量的变化。用抗小鼠CD3、CD4、CD8a、CD19、IgM或CD45R/220单克隆抗体(mAb)进行细胞免疫荧光染色后,用流式细胞术分析骨髓细胞、胸腺细胞和脾细胞的表型变化。用刀豆蛋白A(ConA)和脂多糖(LPS)分别刺激小鼠的脾细胞,用3H-TdR掺入法检测淋巴细胞增殖活性的变化。用RT-PCR检测小鼠骨髓、胸腺和脾脏中PPARαmRNA的表达。结果与野生型小鼠相比较,PP对PPARα缺陷型小鼠胸腺、脾脏的重量和细胞数,以及ConA和LPS刺激对淋巴细胞增殖反应的影响很小。PP可致野生型小鼠胸腺中CD4 CD8 T细胞数,骨髓中B220 B细胞总数和原/前B细胞数明显减少,但对PPARα缺陷型小鼠的上述T、B细胞亚群无显著影响。PPARαmRNA在小鼠胸腺和脾脏中呈低表达,在骨髓中不表达。结论PPARα在PP诱导的免疫调节中起主要作用,其可通过间接途径影响T、B细胞的发育。     

Treatment of murine lupus with monoclonal antibody to L3T4. II. Effects on immunohistopathology of thymus, spleen, and lymph node

Monoclonal antibody to L3T4 has been used successfully to suppress autoimmunity in the New Zealand black/New Zealand white F1 (B/W) mouse model for systemic lupus erythematosus. To clarify the immunopathology of murine lupus and determine the effects of anti-L3T4 treatment on the cellular composition and histopathology of lymphoid organs, we examined the distribution of lymphocyte subsets in cryostat sections of the thymus, spleen, and lymph nodes of B/W mice. Immunohistologic specimens were obtained from female B/W mice that had received weekly intraperitoneal injections of either rat monoclonal antibody to L3T4 (2 mg/mouse/week) or phosphate buffered saline (200 microliters/mouse/week) from age 5 months until euthanasia at 8 months. B and T cell domains in each organ were identified on serial sections with monoclonal antibody directed against B220 (all B cells), Thy-1.2 (all T cells), L3T4 (helper T cells), and Ly-2 (cytotoxic/suppressor T cells). In control mice, striking cytoarchitectural abnormalities were identified in the thymuses, and the spleen and lymph nodes were hypertrophied relative to anti-L3T4 treated mice. Thymic abnormalities included amplification of medulla, formation of thymomas, and cortical atrophy. Amplified medullary regions and thymomas in B/W mice contained numerous B cells and L3T4+ T cells but few Ly-2+ T cells. The enlarged spleens and lymph nodes of control mice consisted of numerous secondary follicles with germinal centers containing an unusual subpopulation of T cells that expressed L3T4 but not Thy-1.2. In contrast, mice treated with anti-L3T4 did not develop histopathologic changes characteristic of systemic lupus erythematosus in any organ. However, treatment depleted L3T4+ cells from the spleen and lymph nodes, and it modulated the expression of L3T4 by thymocytes. These observations demonstrate that treatment with anti-L3T4 not only interferes with L3T4-dependent T cell functions, but it also prevents progressive abnormalities in lymphoid tissue in lupus-prone B/W mice. This preservation of normal lymphoid structure may contribute to the beneficial effects of anti-L3T4 on autoimmunity.     

The role of ICAM-1/LFA-1 and VCAM-1/VLA-4 interactions on T helper 2 cytokine production by lung T cells of Toxocara canis-infected mice.

In order to study the effect of costimulatory signals on T helper type 2 (Th2) cytokine production, monoclonal antibodies (mAb) against cell adhesion molecules (CAM) were added to cells in culture obtained from the lungs of Toxocara canis (Tc)-infected mice followed by the determination of interleukin-5 (IL-5) and IL-4 in the supernatants of the culture. ES-stimulated IL-5 production in the supernatant of total lung cells was reduced by 25% when anti-intercellular adhesion molecule-1 (anti-ICAM-1) mAb, anti-CD11a mAb, or both anti-ICAM-1 and anti-CD11a mAb together were added to the culture. The addition of anti-CD18 mAb had no effects. Anti-vascular cell adhesion molecule-1 (anti-VCAM-1) mAb addition also reduced IL-5 production by 60%, although the addition of anti-very late activation antigen-4 (anti-VLA-4) mAb or both anti-VCAM-1 and anti-VLA-4 mAb together were less effective. In the case of anti-CD3 mAb stimulation, similar effects of mAb to CAM were observed. In contrast, IL-4 production induced by anti-CD3 mAb was reduced more markedly by the addition of either anti-ICAM-1 or anti-CD11a mAb than the combination of anti-VCAM-1 and anti-VLA-4 mAb. Similar effects of mAb to CAM were observed on the production of IL-5 and IL-4 by CD4+ T cells purified using a fluorescence-activated cell sorter. Coincubation with adherent cells was necessary for the significant production of IL-5 and IL-4 by CD4+ T cells. These results suggest that the VCAM-1/VLA-4 interaction is more important for IL-5 production by CD4+ T cells in the lungs of Tc-infected mice, and that the ICAM-1/lymphocyte function-associated antigen-1 interaction is more important for the production of IL-4.     

Intrathyroidal lymphocyte subsets, including unusual CD4+ CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells, in autoimmune thyroid disease.

Intrathyroidal lymphocyte subsets were analysed in 13 euthyroid patients with autoimmune thyroid disease by two-colour flow cytometry and compared with subsets in peripheral blood. In both Graves' and Hashimoto's diseases, proportions of intrathyroidal CD5- B cells were higher than in peripheral blood. The numbers of such cells were correlated with serum levels of anti-thyroid microsomal antibodies. Proportions of T cells bearing alpha beta chains of T cell receptors (TCR alpha beta+ T; T alpha beta) and CD16+CD57+ natural killer (NK) cells were lower in the thyroid, but proportions of CD3hiTCR alpha beta-TCR gamma delta+ (T gamma delta) cells were not different. Proportions of CD4+Leu-8- helper T cells and CD4+CD57+ germinal centre T cells were higher and proportions of CD4+Leu-8+ suppressor-inducer T cells and CD8+CD57+ or CD8+CD11b+ suppressor T cells were lower than in the blood in both diseases. Proportions of CD5+ B cells were high in Graves' disease, and proportions of CD8+CD11b- cytotoxic T cells were high in Hashimoto's disease. Unexpectedly, CD4+CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells were present in thyroid tissues of both diseases. These findings suggest that: (i) an imbalance in the numbers of regulatory T cells and of NK cells that had appeared in the thyroid resulted in the proliferation of CD5- B cells, which were related to thyroid autoantibody production; (ii) CD5+ B cells and cytotoxic T cells are important for the different pathological features in Graves' and Hashimoto's diseases, respectively; and (iii) intrathyroidal CD4+CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells may be related to the pathogenesis of autoimmune thyroid disease.