再生障碍性贫血患者Th及NKT细胞IFN-γ和IL-4的表达及意义

目的:探讨Th及NKT细胞内细胞因子(Intracellular cytokine,ICK)在再生障碍性贫血(Aplastic anemia,AA)发病中所起的作用。方法:流式细胞术(FCM)检测Th细胞表面CD3+CD4+分子、NKT细胞表面CD3+CD16+56+分子,细胞内染色技术检测Th、NKT细胞内IFN-γ和IL-4水平。结果:AA患者外周血Th细胞减少(P<0.01),细胞内CD3+CD4+IFN-γ+、CD3+CD4+IL-4+均增高,Th1/Th2增高(P<0.01);NKT细胞增多(P<0.05),NKT细胞内IL-4+水平升高(P<0.05),IFN-γ+水平无统计学差异。结论:AA的发病与T淋巴细胞异常密切相关,是一种Th1型反应。NKT细胞可代偿调节AA患者IFN-γ和IL-4比例。     

泡球蚴感染小鼠中Tim-3 对Th1 / Th2 细胞因子平衡的影响作用研究

目的:研究泡球蚴感染小鼠Tim-3、Th1细胞因子γ干扰素(IFN-γ)、Th2细胞因子白细胞介素4(IL-4)的变化。方法:建立泡球蚴感染小鼠模型和对照组,取小鼠脾脏,分离脾淋巴细胞,流式细胞技术检测脾淋巴细胞Th1和Th2细胞水平以及Tim-3在Th1和Th2上的表达水平,用流式微珠阵列技术(CBA)法检测小鼠外周血清中IFN-γ、IL-4水平。结果:与正常对照组相比,泡球蚴感染小鼠脾淋巴细胞Tim-3在Th1中表达增高,Tim-3+Th1细胞与IFN-γ水平呈负相关。结论:泡球蚴诱导小鼠Tim-3在Th1细胞高表达,下调Th1免疫应答介导了Th1/Th2失衡。     

黄芩茎叶总黄酮对胶原性关节炎小鼠Th1/Th2细胞平衡的调节

目的观察黄芩茎叶总黄酮对Ⅱ型胶原诱导性关节炎小鼠脾淋巴细胞Th1、Th2及其相关细胞因子IL-10、IFN-γ的影响,初步探讨黄芩茎叶总黄酮对类风湿性关节炎的作用。方法选用C57BL/6小鼠,建立鸡Ⅱ型胶原诱导性关节炎小鼠模型,将造模成功的小鼠随机分为CIA模型组、黄芩茎叶总黄酮组、雷公藤多苷组,另设正常对照组,于初次免疫后第21天开始灌胃给药,35 d后流式细胞术检测小鼠脾淋巴细胞Th1、Th2水平及相关细胞因子IL-10、IFN-γ的表达。结果与模型组比较,药物组小鼠CD4+T淋巴细胞中Th1细胞数量明显降低(P0.05),Th2比例增加(P0.01),药物组IL-10分泌显著增多(P0.05),IFN-γ分泌明显减少(P0.05),2用药组无明显差异(P0.05)。结论黄芩茎叶总黄酮可以调节Th1/Th2的平衡及其相关细胞因子IFN-γ、IL-10的表达。     

慢性乙肝患者树突状细胞对Th1/Th2分化的影响

探讨慢性乙肝患者树突状细胞(dendritic cells,DC)对CD4+Th细胞亚群分化的影响。分离慢性乙肝患者外周血单个核细胞(PBMC),以rhIL-4(50 ng/ml)、rhGM-CSF(10 ng/ml)和rhTNF-α(100 u/ml)诱导培养DC。以流式细胞仪检测DC表面CD1a、CD83、CD80、CD86、HLA-DR分子表达情况。MTT法检测DC刺激同种异体淋巴细胞增殖能力。免疫磁珠分离外周血CD4+T细胞亚群,PMA+Ionomycin刺激后胞内荧光染色,流式细胞仪检测辅助性T细胞(helper T cell,Th)内特征性细胞因子IFN-γ/IL-4以判断Th1/Th2分化。ELISA法检测DC或Th细胞培养上清中IL-6、IL-12、IFN-γ和IL-4的含量。结果:慢性乙肝患者的DC表达CD1a、CD83、CD80、CD86、HLA-DR分子水平明显低于正常人(P<0.01);培养至第7天,慢性乙肝患者DC分泌的IL-12水平低于正常人(P<0.01),而分泌的IL-6水平增高(P<0.05)。与正常人相比,慢性乙肝患者外周血中Th1细胞占CD4+T细胞的百分比较低(P<0.01),其Th细胞培养上清中IFN-γ的量也较低(P<0.01)。患者DC与同种异体的健康人Th细胞共培养,刺激Th1型细胞因子IFN-γ产生的能力低于正常人(P<0.01)。慢性乙肝患者体内DC功能的异常可能导致了外周血Th1细胞分化不足。     

乳杆菌对原代淋巴细胞中Th1/Th2细胞平衡的影响

目的:分析7种乳杆菌对原代淋巴细胞增殖和细胞因子(CK)分泌的作用,进而探讨其对Th1/Th2细胞平衡的影响。方法:用不同种属、不同浓度的活的/热致死的乳杆菌体外作用于小鼠脾淋巴细胞培养60 h后,采用MTT比色法检测淋巴细胞的增殖效果。用ELISA法检测Th1型细胞因子(IL-12、IFN-γ)、Th2型细胞因子(IL-4、IL-10)和调节型细胞因子(TGF-β)的分泌量。结果:活的/热致死的乳杆菌单独作用,就能促进淋巴细胞体外增殖并表现出剂量依赖关系(P<0.05)。当菌的浓度为107集落形成单位(CFU)/mL(即细菌与细胞的比例为10∶1)时,热致死的发酵乳杆菌和嗜酸乳杆菌的免疫活性近似于活菌。而且,这两株热致死菌还可适当提高淋巴细胞分泌IL-12和IFN-γ,抑制IL-4、IL-10和TGF-β的分泌,使其IFN-γ/IL-4的比值(代表Th1/Th2细胞平衡)均显著高于刀豆蛋白A(ConA)对照组(P<0.05)。结论:乳杆菌可通过提高淋巴细胞的IFN-γ/IL-4分泌率来促进Th1优势状态的Th1/Th2细胞平衡,并具有菌株特异性。     

MiR-143在Lewis肺癌小鼠外周血中的表达及其对Th1/Th2平衡的影响

目的 利用小鼠Lewis肺癌移植肿瘤模型探究肺癌疾病进展过程中外周血微小RNA的表达及其对Th1/Th2平衡的调控作用。方法 利用Real-time PCR实验检测血浆中miR-143、miR-217、miR-195和miR-615的表达水平;用酶联免疫吸附实验（ELISA）检测小鼠外周血血清IFN-γ、IL-2、IL-4和IL-10表达水平,用流式细胞术检测小鼠脾脏CD4+IFN-γ+Th1细胞及CD4+IL-4+Th2细胞比例,测量并统计荷瘤小鼠皮下接种部位肿瘤体积及肺部转移性结节;分离小鼠外周血CD4 T细胞,检测转录因子T-bet和GATA3的表达。结果 与Normal组相比,LCC组小鼠外周血血清miR-143表达水平显著上升,miR-217、miR-195和miR-615表达水平没有明显变化。与Normal组相比,LCC组小鼠外周血Th1相关细胞因子表达水平及脾脏Th1细胞比例下降,而Th2相关细胞因子表达水平上升,且Th1/Th2比率显著下降。而Anti-miR-143组Th1相关细胞因子及Th1细胞比例升高,且Th2相关细胞因子比例下降。与LCC组相比,Anti-miR...     

Th1和Th2型细胞因子在不同MHC-B单倍型鸡群中的转录分析

目的研究鸡体内细胞因子的基础转录水平。方法利用双重荧光定量RT-PCR(dqRT-PCR)技术,对70日龄的5种主要组织相容性复合体(Major histocompatablity complex,MHC)单倍型无特定病原体(special pathogen free,SPF)鸡群G1、G2、G3、G5和G7的肺组织(包括气管)、胸腺、法氏囊、脾脏和外周血淋巴细胞(PBL)中Th1型(IFN-γ、IL-18)和Th2型(IL-4、IL-10)细胞因子mRNA含量进行定量检测。结果 IFN-γ和IL-4在各鸡群的胸腺中转录水平最高,IL-18和IL-10在法氏囊中最高,Th2型细胞因子在脾脏中最低;初级免疫器官(胸腺、法氏囊)中IFN-γ和IL-10转录水平在G3鸡群中最高。结论 70日龄时Th1型和Th2型细胞因子在SPF鸡的初级免疫器官中转录水平较高,且为制衡状态,胸腺中表现为IFN-γ和IL-4相互制衡,法氏囊中为IL-18与IL-10;不同MHC单倍型鸡体内细胞因子转录水平有所差异,但未达到显著水平。     

CCK-8对KLH免疫小鼠脾细胞Th1/Th2平衡的影响

目的： 探讨八肽胆囊收缩素（CCK-8）对Th1/Th2平衡的调节作用。方法: 给予BALB/c小鼠钥孔戚血蓝蛋白（KLH）免疫同时体内给予不同剂量的CCK-8,酶联免疫吸附试验(ELISA)检测其脾细胞培养上清中Th1型细胞因子γ-干扰素(IFN-γ)、白细胞介素-2（IL-2）和Th2型细胞因子白细胞介素-4（IL-4）、白细胞介素-5（IL-5）水平,逆转录聚合酶链式反应(RT-PCR)法检测脾细胞中IFN-γ、IL-2、IL-4、IL-5 mRNA表达;ELISA法检测血清中Th1型抗KLH抗体IgG2a和Th2型抗KLH抗体IgG1水平。结果: ①KLH免疫使小鼠脾细胞分泌Th1/Th2型细胞因子水平明显增高,mRNA表达增高,KLH免疫同时给予CCK-8可使脾细胞培养上清中IFN-γ、IL-2含量进一步增加和IFN-γ、IL-2mRNA表达增高,而使IL-4、IL-5含量降低,IL-4、IL-5 mRNA表达减低和降低IL-4/IFN-γ比值。②KLH免疫小鼠血清中IgG2a、IgG1发生不同程度增高,CCK-8可使其血清中IgG1水平减低而使IgG2a水平增高。结论: CCK-8可促进KLH免疫小鼠体内Th1反应,使Th2优势反应向Th1方向转变。     

全氟化合物与儿童哮喘及Th1/Th2免疫应答平衡相关性研究

目的 采用病例对照探讨全氟化合物(PFAAS)暴露与儿童哮喘及Th1型细胞因子白细胞介素(IL)-2,干扰素(IFN)-γ和Th2型细胞因子(IL-4,IL-5)分泌水平的关系.方法 选择231名台北医院就诊的哮喘儿童作为病例组,来自社区的225名自然儿童作为对照组.采用双抗体酶联免疫吸附实验(ELISA)试剂盒检测儿童血清中细胞因子IL-2、IFN-γ、IL-4和IL-10的分泌水平;高效液相色谱仪分析血清中全氟辛烷磺酸(PFOS)和全氟辛酸(PFOA)水平.结果 哮喘儿童机体PFOS(33.9μg/L比28.9 μg/L)和PFOA(1.2μg/L比0.5 μg/L)暴露负荷显著的高于对照组儿童,且随着机体PFAAs的增高,儿童患有哮喘的风险呈增高趋势.对哮喘儿童而言,血清PFAAs水平与Th1型细胞因子(IL-2,IFN-γ)存在显著的负相关,而与Th2型细胞因子(IL-4,IL-5)呈正相关关系.结论 PFOS暴露可诱导机体免疫应答平衡紊乱,并向Th2型免疫应答极化.     

Tim-3/galectin-9调控脂多糖诱导的人淋巴细胞中Th1/Th2细胞平衡

目的 探讨T细胞免疫球蛋白黏蛋白分子-3(Tim-3)/半乳糖凝集素-9(galectin-9)在脂多糖(LPS)诱导淋巴细胞炎性过程中对辅助性T细胞(Th)Th1/Th2细胞失衡中的作用。方法 收集脓毒症患者的外周血。分离外周血单个核细胞(PBMC),RT-qPCR检测Tim-3、galectin-9、T-bet和GATA3的表达；ELISA检测血清sTim-3、galectin-9、IFN-γ和IL-4的水平；分离的外周血单个核细胞体外培养，LPS刺激建立体外炎性模型；ELISA法检测细胞培养上清中Th1和Th2细胞相关细胞因子的水平；Western blot检测JAK2/STAT3相关因子的表达；Pearson相关系数分析Tim-3、galectin-9、IFN-γ和IL-4的相关性。结果 脓毒症患者外周血中Tim-3和galectin-9的mRNA表达增多，sTim-3、galectin-9、IL-4和GATA-3升高，IFN-γ和T-bet水平下降，磷酸化JAK2和STAT3升高(P<0.05)。阻断Tim-3表达后，IFN-γ水平升高，而IL-4的水平明显下降，磷酸化...     

胎盘NKT细胞在小鼠原因不明多发性流产中的作用研究

目的:通过检测原因不明多发性流产模型(CBA/J雌鼠×DBA/J雄鼠)小鼠胎盘中的NKT的细胞数量、成熟度和细胞因子的分泌格局,以探索NKT细胞失调在原因不明多发性流产中的可能作用.方法:分别建立正常妊娠模型(CBA/J雌鼠×BALB/C雄鼠)和原因不明多发性流产模型,用流式细胞仪检测滋养层细胞中NKT细胞和CD3~+T数量的变化,用ELISA方法检测Th1/Th2相关细胞因子,而胎盘淋巴细胞T-bet表达水平用荧光定量PCR法检测.结果:正常妊娠组与原因不明多发性流产组CD3~+T细胞数量无显著性变化(P＞0.05);正常妊娠过程中,胎盘淋巴细胞分泌IFN-γ的量逐渐下降,伴随有NKT细胞数量、成熟型比例逐渐下降,而原因不明多发性流产妊娠过程中则相反;多发性流产组与正常妊娠组相比,T-bet mRNA存在表达异常,并与NKT细胞成熟型比例、胎盘淋巴细胞分泌IFN-γ的量成正相关.结论:原因不明多发性流产的发生,可能与NKT细胞失调相关,妊娠早期与胎盘NKT细胞成熟型比例偏低,分泌IFN-γ不足有关,而妊娠中后期则与NKT细胞成熟型比例偏高,分泌IFN-γ过量有关,T-bet mRNA的表达异常是造成NKT细胞失调的因素之一.     

急性心肌梗死后辅助性T细胞功能失衡的意义

目的：探讨急性心肌梗死(AMI)后辅助性T淋巴(Th)细胞功能失衡的意义。方法： 采用流式细胞分析法对33例AMI病人，22例不稳定心绞痛(UA)病人和35例AMI大鼠进行Th细胞胞内干扰素γ(IFN-γ)和白介素4(IL-4)的动态监测，同时应用RT-PCR方法检测AMI大鼠心肌组织IFN-γ和IL-4以及T细胞表面趋化因子受体CCR3、CCR5和CXCR3 mRNA的表达。结果：AMI和UA病人发病24 h内Th1型胞内IFN-γ的水平明显高于对照组。UA患者IFN-γ高表达持续时间较短，发病1周后恢复；AMI患者IFN-γ高表达持续时间较长，发病后1周甚至1月仍增高。Th2型胞内IL-4未见明显变化。AMI大鼠心梗后Th细胞胞内IFN-γ和IL-4均无明显变化，T细胞表面趋化因子受体CCR3、CCR5和CXCR3 mRNA表达亦无显著差异，但AMI 1周、2和1月末心肌组织局部IFN-γ mRAN的表达明显增加。结论： AMI后机体出现T细胞功能失衡，主要表现为Th1细胞功能亢进，可能参与AMI的发病；AMI后T细胞功能失衡可能作为自身免疫病的发病机制之一，参与了AMI后自身免疫性心肌炎的发病和自身免疫因素引起的心肌损伤和心室重塑过程。     

A Mixed Th1/Th2 Cell Cytokine Response Predominates in Systemic Onset Juvenile Rheumatoid Arthritis: Immunoregulatory IL-10 Function

The immune response identified by the induction of Th1/Th2 cells plays a critical role in the pathogenesis of various inflammatory and immune disorders. We have determined that in children with systemic onset juvenile rheumatoid arthritis (JRA), peripheral blood mononuclear cells (PBMC) constitutively and after stimulation with various antigensin vitroinduce a higher secretion of interleukin-4 (IL-4) and IL-10 with a characteristic deficiency of IL-2 and interferon-γ (IFN-γ). This cytokine pattern is a representative of a mixed Th1/Th2 cell response in JRA. The CD3/CD28 costimulatory molecule was found to be a potent inducer of IL-4 and IL-10 secretion. PBMC-derived augmented IL-10 secretion was inhibited by exogenous Th1 cell type recombinant cytokines (IL-2, IL-12, and IFN-γ). Although IL-10 inhibits PBMC-induced proinflammatory IL-1α and tumor necrosis factor-α secretion, it had no major effect on IL-6 production. The finding of a distinctly enhanced mixed Th1/Th2 cell response cytokine (IL-4 and IL-10) pattern in JRA provides a framework for developing strategies for immunologic intervention in this rheumatic disorder in children.     

The Th1 and Th2 cytokines IFN-γ and IL-4 antagonize the inhibition of monocyte IL-1 receptor antagonist by glucocorticoids: involvement of IL-1

Monocytes express IL-1 and IL-1 receptor antagonist (IL-1Ra) in response to lipopolysaccharide (LPS). IL-1 self-induction contributes to the increase in IL-1 following LPS stimulation. LPS-stimulated IL-1 and IL-1Ra production are inhibited by glucocorticoids. In the present work we examined the regulation of IL-1Ra by Th1 cytokine IFN-γ, Th2 cytokine IL-4, glucocorticoids and IL-1 in human monocytes. We demonstrate that IL-1 contributes to LPS-induced IL-1Ra expression as shown by IL-1 blockade in LPS-stimulated monocytes using a specific anti-IL-1β antibody or recombinant IL-1Ra. Glucocorticoids inhibited IL-1β-stimulated IL-1Ra mRNA expression and protein production. Glucocorticoids inhibited both IL-1-mediated and non-mediated LPS stimulation of IL-1Ra expression. Both IFN-γ and IL-4 reversed the inhibitory effect of glucocorticoids on IL-1Ra expression and secretion. The effect of IFN-γ was blocked by pretreatment of monocytes with an anti-IL-1β blocking antibody, whereas the effect of IL-4 could not be blocked, demonstrating that IFN-γ acts through a mechanism dependent on endogenous IL-1 production, whereas IL-4 acts through an IL-1-independent one. Consistent with this finding, IFN-γ (but not IL-4) failed to reverse the inhibitory effect of glucocorticoids when stimulated by IL-1, and only IL-4 combined with IL-1 showed synergism resulting in an increase in IL-1Ra production. The differential regulation and involvement of IL-1 in the expression of IL-1Ra by IFN-γ, IL-4 and glucocorticoids sets the level of monocyte responsiveness during the Th1 or Th2 responses.     

Insect venom immunotherapy induces interleukin-10 production and a Th2-to-Th1 shift,and changes surface marker expression in venom-allergic subjects

The current study was carried out to elucidate the immunoregulatory changes induced by venom immunotherapy (VIT) in bee or wasp allergic subjects. All subjects included in this study had a history of severe systemic allergic reactions to stings of the respective insect as well as positive skin tests with the respective venom or venom-specific IgE in the sera. Parameters assessed in peripheral blood mononuclear cells (PBMC) before and after initiation of VIT (rush therapy reaching a maintenance dose of 100 μg venom injected subcutaneously within 1 week) were expression of CD3, CD4, CD8, CD45RA, CD45R0, interleukin (IL)-2 receptor (R)α, IL-4R, IL-12R, FcσRII, CD40, and CD40 ligand (CD40L), cells producing interferon (IFN)-γ and IL-10 after stimulation with phorbol 12-myristate 13-acetate + ionomycin in the presence of monensin measured by flow cytometry; secretion of IFN-γ, IL-4, and IL-10 measured by ELISA (IFN-γ and IL-10 were additionally measured by PCR), and proliferation after stimulation with the respective venom. Significant decreases were observed after VIT for proliferative response to venom and venom + IL-4, IL-4 secretion, FcσRII, CD40, and CD40L expression. Significant increases were observed after VIT for IFN-γ concerning the amount secreted and the number of producing cells, and IL-10. IL-10 was mainly produced by CD4⁺ cells that were negative for IFN-γ, but some double-positive (IL-10 and IFN-γ) cells were always detected. Addition of blocking anti-IL-10 antibodies, but not isotype control antibodies, prevented down-regulation of proliferation (but not IL-4 secretion) and further enhanced IFN-γ secretion after VIT. These data indicate that in insect venom allergic subjects, VIT not only induces a rapid shift in cytokine expression from Th2 to Th1 cytokines, but also leads to induction of the immunosuppressive cytokine IL-10, which may be important for the limitation of potentially harmful allergen-specific Th1 responses. The described changes in cytokine expression may be responsible for subsequent increases in allergen-specific IgG and decreases in IgE production, as well as suppressive activity observed in earlier studies.     

Adjuvant effect of zinc oxide on Th2 but not Th1 immune responses in mice

Background and aim: We investigated the effect of zinc oxide (ZnO) on Th1 and Th2 immune responses in mice.

Material and methods: Mice were intraperitoneally administered with ovalbumin (OVA) with or without varying doses of ZnO (day 0). On day 21, anti-OVA IgG, IgG2a, IgG1, and IgE antibodies in sera, OVA-specific proliferative responses of spleen cells, and production of Th1 cytokines including IFN-γ as well as Th2 cytokines such as IL-4 and IL-5 were measured.

Results: The results showed that administration of OVA with ZnO was followed by greater increases in anti-OVA IgG and the antigen-specific splenocyte proliferation compared to that of OVA alone. The production of anti-OVA IgG1 and IgE and secretion of IL-4 and IL-5 were markedly enhanced by ZnO. The enhancing effect of ZnO on these Th2 responses was as strong as aluminium hydroxide (Alum) that was widely used as an adjuvant. In contrast, treatment with OVA plus ZnO failed to affect production of anti-OVA IgG2a as well as IFN-γ. It was also observed that ZnO had a stimulating effect on the secretion of the proinflammatory cytokine IL-17 from a new lineage of effector Th cells.

Conclusion: These results suggest that ZnO appears to have an adjuvant effect on the immune system, especially Th2 but not Th1 immune responses.     

Th17 cells: new players in asthma pathogenesis

CD4+ T effector lymphocytes are distinguished in different subsets on the basis of their patterns of cytokine secretion. Th1 cells, thank to IFN-γ production, are responsible for cell-mediated immunity against intracellular pathogens, Th2 cells, through the production of IL-4, provide some degree of protection against helminthes, and Th17 cells, via IL-17, promote neutrophils recruitment for the clearance of bacteria and fungi. However, beyond their protective role, these T-helper subsets can also be involved in the pathogenesis of several inflammatory diseases. Asthma is an inflammatory disease characterized by different clinical phenotypes. Allergic asthma is the result of an inflammatory process driven by allergen-specific Th2 lymphocytes, whereas Th17 cells are mainly involved in those forms of asthma, where neutrophils more than eosinophils, contribute to the inflammation. The identification in allergic asthma of Th17/Th2 cells, able to produce both IL-4 and IL-17, is in keeping with the observation that different clinical phenotypes can coexist in the same patient. In conclusion, a picture in which different T-cell subpopulations are active in different phase of bronchial asthma is emerging, and the wide spectrum of clinical phenotypes is probably the expression of different cellular characters playing a role in lung inflammation.     

Relationship between Th1/Th2 cytokine patterns and the arthritogenic response in collagen-induced arthritis

It is hypothesized that the balance of cytokines produced by Th1/Th2 subsets of T helper cells plays an important role in the development of autoimmune diseases. Murine collagen-induced arthritis (CIA) is an example of an autoimmune disease in which immunization with cartilage-derived type II collagen induces, firstly, a T cell response to type II collagen and, secondly, the manifestation of a destructive inflammatory response in affected joints. We have investigated the role of Th1/Th2 responses in the development of CIA by monitoring levels of interferon (IFN)-γ (a Th1 cytokine) and interleukin (IL)-4 and IL-10 (Th2 cytokines), and IL-1β and tumor necrosis factor (TNF) (pro-inflammatory cytokines) produced by cultured draining lymph node cells (LNC) from collagen-immunized DBA/1 mice during the induction phase of arthritis and throughout the time of clinical manifestation and subsequent remission of the disease. Although a transient increase in IL-10 was detected 3 days after immunization, Th2 cytokine production was found to be almost completely suppressed 6 days after immunization. In contrast, IFN-γ was detected in LNC cultures as early as 6 days after immunization and the addition of type II collagen to the culture medium resulted in an approximately 10-fold increase in IFN-γ production, indicating that a predominantly Th1 response had become established by this time. IFN-γ production by LNC was found to be further increased at the time of clinical manifestation of arthritis and could be up-regulated by co-culture with type II collagen. IL-10 was not detected in LNC cultures at the onset of arthritis and IL-4, although present, was found to be markedly suppressed in LNC cultures containing type II collagen. These findings indicate that Th1 responses are predominant at the time of onset of arthritis and that the activation of collagen-specific Th1 cells may result in suppression of Th2 activity. IFN-γ production declined progressively during the progression and subsequent remission of arthritis whereas levels of IL-10 increased and low, though persistent, levels of IL-4 were detected throughout this period. High levels of IL-1β and TNF-α production were detected at the onset of the disease. The role of Th1 responses in the development of CIA was further emphasized by the observation that immunization of mice with type II collagen in incomplete Freund's adjuvant, which normally fails to induce arthritis, resulted in a predominantly Th2 cytokine profile.