真核表达4-1BBL调节淋巴细胞功能活性及抗肿瘤效应的研究

目的：在非免疫非肿瘤细胞中转染表达4-1BBL，并研究4-1BBL在调节淋巴细胞功能活性及抗肿瘤方面的作用和机制。方法：构建含有4-1BBL全长eDNA序列的表达质粒p4-1BBL，脂质体介导体外转染BHK细胞，G418筛选出阳性克隆，RT-PCR、免疫细胞化学染色及免疫印迹检测4-1BBL的表达，检测BHK细胞表达的4-1BBL对脾淋巴细胞增殖和杀伤活性的影响；建立小鼠H22肝细胞癌移植瘤模型，裸DNA肌肉注射法体内转染表达4-1BBL进行肿瘤治疗，检测肿瘤生长速度；另外，利用免疫组化染色法分析瘤周组织中CD8^＋T淋巴细胞。结果：BHK细胞转染表达的4-1BBL能够显著增强肿瘤抗原肽激活的脾淋巴细胞增殖和杀瘤活性（P〈0．01），并显著提高IL-2和IFN-γ表达水平（P〈0．01），同时增强非特异性免疫杀伤活性。肿瘤接种部位转染表达4-1BBL，瘤周组织中CD8^＋T淋巴细胞数量显著增加（P〈0．01），肿瘤生长速率显著低于生理盐水对照组和空载体对照组（P〈0．01）。结论：在肿瘤微环境中的正常细胞转染表达4-1BBL，能够有效促进T细胞增殖及杀伤等功能活性，可望成为肿瘤免疫生物治疗的一种新的手段。     

癌胚抗原基因重组疫苗的构建及免疫效果观察

目的：探讨含癌胚抗原（CEA）部分编码基因的真核重组质粒pIRES-CEAⅢ用于CEA阳性肿瘤免疫治疗可能性。方法：应用基因重组技术构建了含CEA信号肽和Ⅲ区编码序列的真核表达质粒pIRES，CEAⅢ，肌注免疫BALB／c小鼠，再分别应用野生型小鼠肝癌细胞H22及CEAcDNA全序列转染的Hn细胞进行小鼠皮下接种，观察基因重组疫苗对CEA阳性肿瘤的抑制作用及其诱导小鼠细胞毒性T淋巴细胞（CTL）特异性杀伤CEA阳性肿瘤细胞的能力。结果：pIRES-CEAⅢ真核重组质粒免疫组小鼠CEA阳性肿瘤的生长速度趋缓，瘤块较小，与对照组小鼠（免疫空载体质粒和接种野生型H控细胞）相比有明显差异（P〈0．05）；经pIRES-CEAⅢ重组质粒免疫的小鼠脾细胞对H22．CEA（＋）细胞的杀伤率明显升高，差异显著（P〈0．01）；但对H22细胞则没有明显的杀伤作用。结论：pIRES-CEAⅢ作为基因疫苗可以抑制CEA阳性肿瘤在小鼠体内的生长，诱导小鼠CTL对CEA阳性肿瘤细胞的特异性杀伤。     

MUC1基因疫苗对膀胱肿瘤抑制的免疫学实验研究

目的：研究人粘蛋白MUC1基因DNA疫苗诱导小鼠细胞毒性T细胞（CTL）及体液免疫应答的作用，为膀胱癌的疫苗治疗提供实验资料。方法：接种pcDNA3．1（＋）-MUC1质粒，通过ELISA法检测小鼠血清MUC1抗体生成和脾细胞产生IL-2和1FN-7的量，通过LDH释放法测定CTL对BIU-87细胞的杀伤活性。结果：接种pcDNA3．1（＋）-MUC1疫苗后，小鼠血清中抗MUC1抗体水平明显升高，与对照组相比有显著性差异（P〈0．01）。脾细胞产生的IL-2和IFN-7水平较对照组高（P〈0．01）。在效靶比为100：1、50：1、25：1、12．5：1时，MUC1基因疫苗免疫组小鼠CTL对BIU-87杀伤率（分别为58．4％、47．2％、35．7％、27．4％），较空载体pcDNA3．1（＋）组小鼠和灭菌生理盐水组小鼠（分别为11％、19．2％、9．5％、14％和16．5％、11．9％、8．6％、10．3％）均明显升高，且有显著性差异（P〈0．01）。结论：MUC1基因DNA疫苗能够诱导小鼠产生抗MUC1特异性抗体，诱导产生杀伤表达MUC1细胞的CTL，为MUC1基因疫苗用于膀胱肿瘤生物治疗提供了一定的实验依据。     

小鼠CTL体外非特异性扩增对其杀瘤活性的影响

目的 在体外用抗CD3单抗、抗CD28单抗和白细胞介素2（IL－2）扩增肿瘤特异性CTL,为肿瘤过继治疗提供足够数量的、具有高度杀瘤活性的效应细胞。方法 采用两种方案培养肿瘤细胞免疫的小鼠脾细胞。（1）抗CD3单抗刺激48h后,加入抗CD3单抗和20U／mlrIL－2（抗－CD3＋IL－2组）;（2）抗CD3单抗和抗CD28单抗同时刺激48h后,加入抗CD3单抗、抗CD28单抗和20U／ml rIL－2（抗－CD3＋抗－CD2＋IL－2组）。分别检测2组效应细胞的增殖水平、杀瘤活性及表型。结果 抗CD3＋IL－2组细胞的^3H－TdR掺入量在第6天、12天、20天分别为22126、52426、2072,抗－CD3＋抗－CD28＋IL－2组细胞的^3H-TdR掺入量在第6天、12天、30天分别为32168、12922、3265,后者明显高于前者。在培养12d时,抗－CD3＋IL－2组细胞对FBL03的最大杀伤活性为66．4％,抗－CD3＋抗－CD28＋IL－2组细胞对FBL－3的最大杀伤活性为77．8％。细胞表型FACS分析结果表明,抗－CD3＋抗－CD28＋IL－2组培养12d后的细胞90％以上为Thy1.2^ 细胞,且CD25^ 细胞在抗－CD3＋抗－CD28＋IL－2组、抗－CD3＋IL－2组分别为23．00％、8．15％。结论 抗CD3单抗、抗CD28单抗和低剂量IL－2同时非特异性刺激,可获得大量扩增的、具有高度杀瘤活性的肿瘤特异性CTL。     

重型乙型肝炎前期免疫学指标分析CSCD

目的观察重型乙型肝炎前期（以下简称重肝前期）细胞免疫及体液免疫状况。方法选取重肝前期患者56例,慢性乙型肝炎患者40例,健康志愿者20例,采用流式细胞仪检测外周血淋巴细胞CD3＋、CD4＋、CD8＋、CD3-／CDl9＋（B细胞）等亚群表达百分比,免疫散射比浊法检测血清IgG、补体c3,并进行统计学分析。结果与慢性乙肝组及健康对照组相比,重肝前期组CD8＋T细胞百分率明显降低（P〈0．01或P〈0．05）,但其CD4＋百分率及CD4＋／CD8＋的比值显著高于慢性乙肝组（P〈0．01或P〈0．05）;慢性乙肝组与重肝前期组外周血B细胞的平均百分率及血清IgG水平差异无统计学意义（P〉0．05）;重肝前期组血清补体c3水平显著下降（P〈0．01或P〈0．05）。结论重型乙肝前期患者存在一定程度的免疫功能紊乱,相对慢性乙肝而言,细胞免疫相对亢进,体液免疫相对受抑。     

发作期哮喘患者外周血T细胞亚群、B细胞和NK细胞的变化及临床意义

目的：探讨发作期哮喘患者外周血T细胞亚群、B细胞和NK细胞变化及临床意义。方法：采用直接免疫荧光法,用流式细胞术检测30例发作期哮喘患者和30例正常人对照的T细胞亚群、B细胞和NK细胞的变化。结果：与正常对照组比较,发作期哮喘患者CD4^＋T细胞、CD19^＋B细胞和CD4^＋／CD8^＋比值显著增高（P〈0．01）,CD8^＋T细胞显著下降（P〈0．01）和CD56^＋CD16^＋NK细胞下降（P〈0．05）。CD3^＋T细胞无明显变化。结论：发作期哮喘患者的免疫功能紊乱在哮喘发病中起着重要作用。     

胃癌患者红细胞C3b受体与淋巴细胞免疫功能的相关性研究

目的：研究胃癌患者红细胞C3b受体（RBC-C3bR）与淋巴细胞免疫功之间的关系。方法：利用酵母菌花环试验、MTT法及克隆抗体致敏花环法对51例胃癌患者及30例正常人的RBC-C3bR、自然杀伤细胞（NK）活性及T淋巴细胞（TC）亚群进行测定。结果：胃癌患者RBC-C3bR阳性率、NK细胞杀伤活性、CD3^＋、CD4^＋、CD4^＋／CD8^＋比值均比正常对照组显著低下（P〈0．05、P〈0．01）。经统计学相关性分析显示，RBC-C3bR阳性率与CD4^＋／CD8^＋比值、NK细胞杀伤活性间呈正相关（P〈0．05，P〈0．01）。结论：胃癌患者红细胞免疫功能与淋巴细胞免疫功能一样受到抑制，二者免疫功能密切联系、相互影响。     

75mGy X线全身照射对小鼠脾细胞抗瘤活性的增强作用

将经７５ｍＧｙＸ线全身照射后小鼠的脾细胞过转移至同系小鼠体内，观察其对肿瘤生长及转移的影响，结果发现，照射组小鼠脾细胞可明显抑制与小混合注射的Ｌｅｗｉｓ肺癌（ＬＬＣ）细胞的生长和自发肺转移（Ｐ〈０．０５～０．０１）。与假照组相比，照射后２４ｈ照射组小鼠脾脏有核细胞数增多（Ｐ〈０．０２），脾细胞对ＣｏｎＡ和ＩＬ－２的反应性增强（Ｐ〈０．００１），ＮＫ细胞毒活性明显提高（Ｐ〈０．０１），提示，脾细胞免     

休克期大面积切痂对严重烧伤大鼠细胞免疫功能影响的研究

目的 观察休克期大面积切痂对严重烧伤大鼠细胞免疫功能的影响，探索改善烧伤后机体免疫功能紊乱的有效方法。方法 将大鼠分成休克期切痂组（A组）、常规切痂组（B组）和正常对照组（C组）。A、B组造成30％TBSAⅢ度烫伤，C组不烫伤。A组伤后第6h、B组伤后第4d切痂，并于伤后第1、5、9d各活杀10只，取材送检，观察其免疫指标的变化。结果 （1）A、B组与C组比较：A、B组烫伤大鼠各时相点CD3^＋T细胞变化不大（P〉0．05），但CD4^＋T细胞、CD4^＋／CD8^＋比值明显下降、CD8^＋T细胞增高（P〈0．05或P〈0．01）。NK细胞活性明显下降（P〈0．05或P〈0.01），外周血CD25^＋T淋巴细胞表达及经活化后脾脏CD25^＋T淋巴细胞表达明显下降（P〈0．05或P〈0．01）。（2）A组与B组比较：A组CD4^＋T细胞、CD4^＋／CD8^＋比值明显升高、CD8^＋T细胞降低（P〈0．05或P〈0．01），NK细胞活性明显升高（P〈0．05或P〈0．01），外周血CD25^＋T淋巴细胞表达及经活化后脾脏CD25^＋T淋巴细胞表达均明显升高（P〈0．05或P〈0．01）。结论 （1）大鼠烫伤后细胞免疫状况发生了明显变化。（2）休克期切痂可以改善烫伤大鼠T淋巴细胞亚群分布，提高NK细胞活性，增加外周血CD25^＋T淋巴细胞的表达。提高经活化后脾脏CD25^＋T淋巴细胞数。从而改善烫伤大鼠伤后机体的细胞免疫功能。     

FBL3细胞在小鼠体内外诱导CD4+CD25+调节性T细胞增殖的实验研究

目的：通过小鼠体内外实验观察肿瘤细胞是否可以诱导CD4^＋CD25^＋Treg的分化增殖。方法：将小鼠的红白血病瘤细胞系FBL3接种于C57BL/6小鼠腹壁皮下,流式细胞仪检测小鼠外周血、脾脏及瘤组织CD4^＋CD25^＋Treg细胞含量,RT-PCR检测小鼠脾脏及瘤组织Foxp3 mRNA的表达;体外实验检测FBL3细胞培养上清液对小鼠脾脏CD4^＋CD25^＋Treg细胞的作用。结果：荷瘤鼠外周血CD4^＋CD25^＋Treg比例与正常鼠比较无统计学差异（P〉0.05）,但荷瘤鼠脾脏CD4^＋CD25^＋Treg比例显著高于正常对照（P〈0.01）,荷瘤小鼠脾脏组织Foxp3 mRNA的表达量明显增加;体外实验表明FBL3培养上清液促使CD4^＋CD25^＋Treg细胞比例增高,并诱导Foxp3 mRNA表达增加。结论：FBL3细胞及其分泌的可溶性物质能诱导CD4^＋CD25^＋Treg细胞的增殖,说明是肿瘤的发生促进了CD4^＋CD25^＋Treg增高。     

The ex vivo Microenviroments in MLTC of Poorly Immunogenic Tumor Cells Facilitate Polarization of CD4^＋ CD25^＋ Regulatory T Cells

CD4^＋CD25^＋ regulatory T （TR） cells play an important role in maintaining a balanced peripheral immune system. Recent studies have shown that TR cells may also play a key role in suppressing anti-tumor immune response. In order to investigate the tumor immune microenvironment and its influence on TR polarization, poorly immunogenic tumor cell line Ds （C57BL/6, H-2^b）, immunogenic tumor cell lines FBL3 （C57BL/6, H-2^b） and H22 BALB/c, H-2^d） were used to establish the syngeneic/allogeneic, poorly immunogenic/immunogenic mixed lymphocytes-tumor cell culture （MLTC）. Our results revealed that the proportion of CD4^＋CD25^＋ T cells in MLTC of syngeneic primed splenocytes stimulated with D5 tumor cells was higher than that with H22 cells （0.43% vs 0.044%, and the similar results appeared in allogeneic splenocytes stimulated with D5 tumor cells （0.39% vs 0.04%）. The splenocytes stimulated with supernatant from syngeneic MLTC of D5 tumor cells demonstrated higher proportion of CD4^＋CD25^＋ cells than that from allogeneic MLTC of D5 tumor cells, and the splenocytes stimulated with supernatant from syngeneic or allogeneic MLTC of H22 tumor cells generated lower proportion of CD4^＋CD25^＋ T cells than that of D5 tumor cells. The TGF-β1 and Th2-oriented cytokines （IL-4 and IL-10） were dominated in supernatants of syngeneic MLTC of poorly immunogenic tumor cells. Our results provided useful information for studying the mechanisms underlying tumor immune surveillance as well as for the tumor immunotherapy.     

CD4(+)CD25(+)FoxP3(+) regulatory T cells suppress Mycobacterium tuberculosis immunity in patients with active disease

CD4(+)CD25(+) regulatory T cells (Treg) play a central role in the prevention of autoimmunity and in the control of immune responses by down-regulating the function of effector CD4(+) or CD8(+) T cells. The role of Treg in Mycobacterium tuberculosis infection and persistence is inadequately documented. Therefore, the current study was designed to determine whether CD4(+)CD25(+)FoxP3(+) regulatory T cells may modulate immunity against human tuberculosis (TB). Our results indicate that the number of CD4(+)CD25(+)FoxP3(+) Treg increases in the blood or at the site of infection in active TB patients. The frequency of CD4(+)CD25(+)FoxP3(+) Treg in pleural fluid inversely correlates with local MTB-specific immunity (p<0.002). These CD4(+)CD25(+)FoxP3(+) T lymphocytes isolated from the blood and pleural fluid are capable of suppressing MTB-specific IFN-gamma and IL-10 production in TB patients. Therefore, CD4(+)CD25(+)FoxP3(+) Treg expanded in TB patients suppress M. tuberculosis immunity and may therefore contribute to the pathogenesis of human TB.     

Differential requirement of CD28 for IL-12 receptor expression and function in CD4(+) and CD8(+) T cells

IL-12 is a potent inducer of IFN-gamma production and Th1 responses. Co-stimulation mediated by B7 has been shown to synergize with IL-12 for optimal IFN-gamma production and proliferation in vitro. In this study, we examined the requirement of CD28/B7 interactions for optimal induction of IL-12 receptor(R) beta1 and beta2 expression and IFN-gamma. IL-12-induced IFN-gamma production and STAT4 nuclear translocation were markedly reduced in CD28(-/-) splenocytes compared to that of wild-type (WT) splenocytes. Analysis of IL-12R expression revealed that IL-12 induced similar levels of IL-12R beta2 mRNA expression in WT and CD28(-/-) cells. In contrast, IL-12R beta1 expression was impaired in CD28(-/-) cells, indicating that expression of IL-12R beta1 and beta2 is differentially regulated by CD28. CD28(-/-) CD4(+) but not CD8(+) cells exhibited a defect in IL-12Rbeta1 expression that was associated with a marked decrease in IL-12 binding as well as IL-12-induced IFN-gamma production. IL-2 could restore IL-12R expression to CD28(-/-) CD4(+) cells, however, this occurred independently of IL-2-induced proliferation. Thus, these findings identify distinct requirements for CD28 in the capacity of CD4(+) and CD8(+) cells to respond maximally to IL-12.     

Tumor-induced suppression of interferon-gamma production and enhancement of interleukin-10 production by natural killer (NK) cells: paralleled to CD4+ T cells

The predominance of type two cytokines in syngeneic B16 tumor-bearing mice was confirmed by analysing supernatant contents and mRNA copies of IFN-gamma, IL-4, IL-5, IL-10 and IL-13 from splenocytes. The cytokine-producing lymphocytes were then examined by double-staining flowcytometry. Both CD4+IFN-gamma+ T cells and DX5+IFN-gamma+ NK cells from spleen significantly declined, interestingly, the declining degrees of DX5+IFN-gamma+ NK cells were much greater than those of CD4+IFN-gamma+ T cells by the percentage in whole NK or T cells or the absolute amounts per spleen at early tumor stage (day 10) or tumor-advanced stage (day 20). In contrast to DX5+IFN-gamma+ NK cells, DX5+IL-10+ NK cells increased during tumor progression, the increasing degrees of DX5+IL-10+ NK cells were also much greater than those of CD4+IL-10+ T cells by the percentage or the absolute amounts. Though the percentage of DX5+IL-4+ NK cells only increased in early tumor stage (day 10), the increasing degree was also greater than that of CD4+IL-4+ T cells. In 20xfield view under laser confocal microscope, the mean numbers of DX5+IFN-gamma+ NK cells and CD4+IFN-gamma+ T cells dramatically declined after tumor inoculation. These results suggest that cytokines produced by NK cells, at least partly, account for the balance of type one and two cytokines as done by T cells, and in some conditions, that the NK1 or NK2 cells were possibly more sensitive to tumor progression.     

Maintenance of CD8(+) T-cell memory following infection with recombinant sindbis and vaccinia viruses

CD8(+) T-cell memory is critical for protection against pathogens poorly controlled by humoral immunity. To characterize two distinct vaccine vectors, the acute and memory CD8(+) T-cell responses to an HIV-1 epitope (p18) expressed by recombinant vaccinia (vp18) and Sindbis (SINp18) viruses were compared. Whereas 9 to 13% of CD8(+) splenocytes were p18 specific during the acute response to vp18, 4% were induced by SINp18 as revealed by class I tetramer staining. Increased T-cell activation by vp18 was confirmed by higher numbers of both p18-specific IFN-gamma-secreting splenocytes and activated CD8(+) and CD4(+) T cells. Although higher frequencies of p18-specific CD8(+) T cells during primary responses correlated with higher frequencies during memory, the overall decline was only two- to threefold during the transition to memory, demonstrating equally efficient maintenance of memory in SINp18- as in vp18-immune mice. Despite modest in vivo activation, SINp18-induced CD4(+) T cells secreted substantial amounts of IFN-gamma and IL-2, potentially contributing to sustained CD8(+) memory. Collectively the data indicate that Sindbis virus recombinants provide effective vaccines for inducing protective memory CD8(+) T cells in the absence of the extensive inflammation and replication associated with vaccinia virus.     

Human CD4(+)CD25(+) thymocytes and peripheral T cells have immune suppressive activity in vitro

CD4(+)CD25(+) T cells in mice and rats are capable of transferring protection against organ-specific autoimmune disease and colitis and suppressing the proliferation of other T cells after polyclonal stimulation in vitro. Here we describe the existence in humans of CD4(+)CD25(+) T cells with the same in vitro characteristics. CD4(+)CD8(-)CD25(+) T cells are present in both the thymus and peripheral blood of humans ( approximately 10 % of CD4(+)CD8(-) T cells), proliferate poorly in response to mitogenic stimulation and suppress the proliferation of CD4(+)CD25(-) cells in co-culture. This suppression requires cell contact and can be overcome by the addition of exogenous IL-2. CD4(+)CD25(+) cells from thymus and blood were poor producers of IL-2 and IFN-gamma, and suppressed the levels of these cytokines produced by CD4(+)CD25(-) cells. However, CD4(+)CD25(+) PBL produced higher levels of IL-4 and similar amounts of IL-10 as CD4(+)CD25(-) cells. Regulatory CD4(+)CD25(+) T cells have an activated phenotype in the thymus with expression of CTLA-4 and CD122 (IL-2Rbeta). The fact that CD4(+)CD25(+) regulatory T cells are present with a similar frequency in the thymus of humans, rats and mice, suggests that the role of these cells in the maintenance of immunological tolerance is an evolutionarily conserved mechanism.     

Anti-inflammatory action of alpha-melanocyte stimulating hormone (alpha-MSH) in anti-CD3/CD28-mediated spleen and CD4(+)CD25(-) T cells and a partial participation of IL-10

alpha-Melanocyte stimulating hormone (alpha-MSH) has been shown to inhibit the production and the effects of pro-inflammatory cytokine by inflammatory cells in innate immunity. We have determined whether alpha-MSH inhibits anti-CD3/CD28-mediated spleen cells and CD4(+)CD25(-) T cells proliferation and its mechanism of action. The proliferation of anti-CD3/CD28-mediated spleen cells and CD4(+)CD25(-) T cells markedly were suppressed by 50-100 nM and 5-100 nM alpha-MSH, respectively. alpha-MSH (100 nM) increased the production of the anti-inflammatory cytokine IL-10 and decreased the production of the pro-inflammatory cytokine IL-2 and IFN-gamma from CD4(+)CD25(-) T cells. Moreover, anti-IL-10 blocking Ab decreased the inhibitory effects of anti-CD3/CD28-mediated spleen cells and CD4(+)CD25(-) T cells proliferation by alpha-MSH, indicating a partial participation of IL-10 in its mechanism of inhibitory action. These results suggest that alpha-MSH may be useful for treatment of autoimmune diseases and transplantation involving innate and adaptive immunity.     

Maturation of dendritic cells for enhanced activation of anti-HIV-1 CD8(+) T cell immunity

Maturation of dendritic cells (DC) to enhance their capacity to activate T cell immunity to HIV-1 is a key step in immunotherapy of HIV-1 infection with DC. We compared maturation of DC derived from HIV-1-uninfected subjects and infected subjects on antiretroviral therapy (ART) or ART na?ve by CD40 ligand (CD40L) and combinations of TLR3 ligand polyinosinic:polycytidylic acid [poly(I:C)] and inflammatory cytokines IFN-gamma, IFN-alpha, IL-1beta, and TNF-alpha. The greatest levels of virus-specific IFN-gamma production by CD8(+) T cells were stimulated by DC treated with CD40L, followed by DC treated with the poly(I:C)-cytokine combination. The highest levels of IL-12p70 were produced by DC treated with CD40L + IFN-gamma, followed by CD40L and the poly(I:C)-cytokine combination. Neutralization of IL-12p70 indicated that it was only partially involved in direct enhancement of antiviral CD8(+) T cell activity. DC stimulation of antiviral CD8(+) T cell reactivity was enhanced by activated CD4(+) T cells at low concentrations but was suppressed at higher CD4(+) T cell concentrations. Maturation of DC with CD40L obviated the need for CD4(+) T cell help and overcame this suppressive activity. Finally, we showed that DC from HIV-1-infected subjects on ART, which were treated with the poly(I:C)-cytokine combination, retained the capacity to produce IL-12p70 and activate anti-HIV-1 CD8(+) T cell responses after restimulation with CD40L, with or without IFN-gamma. Thus, DC from HIV-1-infected subjects can be engineered with CD40L or a poly(I:C)-cytokine combination for enhancing CD8(+) T cell responses to HIV-1, which has potential applications in HIV-1 immunotherapy.     

Both CD4(+)and CD8(+)T cells are required for IFN-gamma gene expression in pancreatic islets and autoimmune diabetes development in biobreeding rats

To study the relative roles of CD4(+)and CD8(+)T cells and their cytokine products in autoimmune diabetes development, we selectively depleted CD4(+)and CD8(+)T cells in autoimmune diabetes-prone (DP) biobreeding (BB) rats, by administrations of anti-CD2 and anti-CD8 monoclonal antibody (mAb) respectively. We then analysed cytokine mRNA expression, by PCR assay, in mononuclear leukocytes isolated from islets and spleens of control and mAb-treated DP-BB rats. Depletion of CD4(+)T cells (by anti-CD2 mAb) in blood, spleen and islets prevented diabetes development in DP-BB rats, and depletion of CD8(+)T cells (by anti-CD8 mAb) delayed and significantly decreased diabetes incidence. Depletion of either CD4(+)or CD8(+)T cells completely prevented IFN-gamma mRNA upregulation in islets of DP-BB rats above the low level expressed in islets of diabetes-resistant (DR) BB rats. Also, IL-10 mRNA levels in islets of DP-BB rats were significantly decreased by depletion of either CD4(+)or CD8(+)T cells, whereas the effects of the anti-T cell mAb on mRNA levels of other cytokines in islets (IL-2, IL-4, IL-12p40, and TNF-alpha) were discordant. In contrast, both mAb treatments significantly upregulated IL-4 and TNF-alpha mRNA levels in spleens of DP-BB rats. These results demonstrate that islet infiltration by both CD4(+)and CD8(+)T cells is required for IFN-gamma and IL-10 production in islets and beta-cell destruction. Depletion of either CD4(+)or CD8(+)T cells may prevent beta-cell destruction by decreasing IFN-gamma and IL-10 production in islets and increasing IL-4 and TNF-alpha production systemically.     

CD4(+) T cell clones producing both interferon-gamma and interleukin-10 predominate in bronchoalveolar lavages of active pulmonary tuberculosis patients.

The pattern of cytokine production in T cell clones derived from bronchoalveolar lavages (BAL) of active pulmonary tuberculosis (TB) patients was analyzed in clones obtained by limiting dilution procedures which expand with high efficiency either total T lymphocytes, independently of their antigen-recognition specificity, or Mycobacterium tuberculosis-specific T cells. BAL-derived clones, representative of CD4(+) cells from five patients with active TB, produced significantly higher amounts of IFN-gamma than BAL-derived CD4(+) clones from three inactive TB donors or four controls (with unrelated, noninfectious pathology). Average IL-4 and IL-10 production did not differ significantly in the three groups. Although these data suggest a predominant Th1 response to M. tuberculosis infection in the lungs, the majority of BAL-derived CD4(+) clones produced both IFN-gamma and IL-10 and the percentage of clones with this pattern of cytokine production was significantly higher in clones derived from BAL of active TB patients than from controls. Only rare clones derived from peripheral blood (PB)-derived CD45RO(+) CD4(+) T cells of both patients (nine cases) and controls (four cases) produced both IFN-gamma and IL-10; instead, the IL-10-producing clones derived from PB T cells most often also produced IL-4, displaying a typical Th2 phenotype. Higher average amounts of IFN-gamma and IL-10 were produced by BAL-derived CD8(+) clones of four active TB patients than of four controls, although the frequency of CD8(+) clones producing both IFN-gamma and IL-10 was lower than that of CD4(+) clones. The M. tuberculosis-specific BAL-derived T cell clones from three active TB patients were almost exclusively CD4(+) and produced consistently high levels of IFN-gamma often in association with IL-10, but very rarely with IL-4. Unlike the BAL-derived clones, the M. tuberculosis-specific clones derived from PB CD45RO(+) CD4(+) T cells of three different active TB patients and two healthy donors showed large individual variability in cytokine production as well as in the proportion of CD4(+), CD8(+), or TCR gamma/delta(+) clones. These results indicate the predominance of CD4(+) T cells producing both the proinflammatory cytokine IFN-gamma and the anti-inflammatory cytokine IL-10 in BAL of patients with active TB.