高压氧对正常及SIRS大鼠脾T淋巴细胞的影响

本实验以SIRS为基础,以免疫功能和炎症反应中具有代表性的脾T淋巴细胞为研究对象,观察高压氧对正常机体以及SIRS状态机体的影响并探讨其可能的机制。健康雄性SD大鼠40只,体重约140~180 g,随机分为5组,每组8只。A组：腹腔注射生理盐水（5 mL/kg）;B组：腹腔注射等量生理盐水,做3次高压氧;C组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）;D组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）,做1次高压氧治疗;E组：腹腔注射酵母多糖-石蜡悬液（500 mg/kg）,做3次高压氧治疗。采用流式细胞仪计算大鼠脾脏淋巴细胞数量及比例。高压氧治疗（B组）降低正常大鼠外周血CD4＋T细胞百分比（P〈0.01）,对CD8＋T细胞无影响,因此CD4＋/CD8＋T细胞比值下降（P〈0.05）。酵母多糖腹腔注射（C组）使大鼠外周血CD4＋、CD8＋T细胞均减少（P〈0.01）,但CD4＋/CD8＋T细胞比值不变。1次和3次HBO治疗（D和E组）可使酵母多糖所致CD4＋T细胞减少（C组）明显恢复（P〈0.01,P〈0.05）,故CD3＋CD4＋/CD3＋CD8＋比值升高（P〈0.01,P〈0.05）,HBO几乎不影响CD8＋T细胞比例（P〉0.05）。酵母多糖导致大鼠脾脏CD4＋和CD8＋T细胞比例减少;高压氧可减少正常大鼠脾脏CD4＋T细胞比例,而增加SIRS脾脏的CD4＋T细胞比例,而对CD8＋T细胞无影响。     

半胱胺盐酸盐对7日龄肉仔鸡免疫指标的影响

目的：以健康的艾维因仔鸡为实验动物,研究在其日粮中添加半胱胺盐酸盐对其免疫指标的影响,并对其作用机理进行了初步探讨。方法：随机将7日龄的肉仔鸡分为4组,分别添加0mg/kg、50mg/kg1、00mg/kg1、50mg/kg CSH。结果：添加CSH提高了肉仔鸡的溶菌酶的活性（P〈0.01）;添加CSH提高了法氏囊指数和脾脏指数：试验组Ⅱ、试验组Ⅲ与对照组比较差异显著;添加CSH显著提高了血清免疫球蛋白IgA水平（P〈0.01）,显著提高了血清IgM水平（P〈0.01）;添加CSH极显著显著增加了T、B淋巴细胞转化率（P〈0.01）。其中试验100mg/kg添加组对于肉仔鸡免疫各指标影响效果最明显。     

赤松茸多糖的提取及对小鼠免疫力的影响

目的：从赤松茸中提取粗多糖,并探讨其对小鼠免疫功能的影响。方法：采用水提醇沉的方法提取赤松茸多糖,取40只雌性昆明小鼠,分为5组,随后用不同剂量的赤松茸多糖（200、100、50 mg/kg·d）灌胃,7 d后检测小鼠脏器指数及血清干扰素γ（IFN-γ）指标;用MTT法研究赤松茸多糖对小鼠脾脏细胞、腹腔巨噬细胞体外增殖影响。结果：体内对照研究显示：赤松茸多糖可有效提高脾脏、胸腺指数及血清IFN-γ水平（P＜0.05）;体外对照研究显示：在区间内,赤松茸多糖可显著促进脾脏细胞（0.25~2 mg/mL,P＜0.05）以及巨噬细胞（0.5～1 mg/mL,P＜0.05）增殖。结论：赤松茸多糖对小鼠免疫力有明显增强作用,对细胞免疫的增强效果尤为显著。     

球花石斛多糖免疫调节作用的研究

本研究目的为评价球花石斛多糖对正常小鼠免疫功能的影响。球花石斛采用碱提醇沉法得到球花石斛多糖,分别以400、600、800mg/kg小鼠灌胃给药连续10d。通过免疫器官重量检测,碳廓清试验,脾脏T、B淋巴细胞转化试验来观察其对免疫功能的影响。结果显示低、中剂量组的脾脏指数与对照组比较有显著性差异(P<0.01),中、高剂量组的吞噬指数、校正吞噬指数和B淋巴细胞增殖能力与对照组比较有显著性差异(P<0.01,P<0.05),表明球花石斛多糖可显著增加脾脏重量,增强巨噬细胞的碳廓清能力和B淋巴细胞的增殖能力。提示球花石斛多糖具有免疫增强作用,是一种良好的免疫调节剂。     

维生素E对TCDD染毒小鼠白细胞介素和T细胞亚群的影响

为研究维生素E(VE)对2,3,7,8四-氯代二苯并-对-二噁英(TCDD)染毒雄性小鼠白细胞介素(IL)和T细胞亚群的影响,我们设计了5个实验组,将40只小鼠随机分为5组,5组动物给予TCDD和维生素E的水平依次为:TCDD 0 ng/kg和VE0 mg/kg、TCDD 100 ng/kg和VE0 mg/kg、TCDD 100 ng/kg和VE20 mg/kg、TCDD 100ng/kg和VE100 mg/kg、TCDD 100 ng/kg和VE500 mg/kg。灌胃7周后取其血液和脾脏,用酶联免疫法测小鼠血清IL的水平,用流式细胞仪法测定脾脏T淋巴细胞亚群的变化。结果表明:TCDD染毒组小鼠血清IL-1α水平明显高于对照组;VE20 mg/kg和100 mg/kg的两组,其血清IL-1α水平均明显低于染毒组;而VE500 mg/kg组,其血清IL-1α水平与染毒组间差异没有统计学意义;TCDD染毒组小鼠血清IL-2水平明显低于对照组;VE100 mg/kg和500 mg/kg两组,其血清IL-2水平明显高于染毒组;TCDD染毒组CD4 T淋巴细胞百分比明显低于对照组;给予VE的三组,其脾CD4 T淋巴细胞百分比与TCDD染毒组相比有升高的趋势,但没有统计学意义;TCDD染毒组小鼠脾CD8 T淋巴细胞百分比明显高于对照组;VE为100 mg/kg组,其脾CD8 T淋巴细胞百分比明显低于染毒组和VE20 mg/kg两组;VE500 mg/kg组,其脾CD8 T淋巴细胞百分比明显低于染毒组。表明TCDD能导致机体白细胞介素分泌的紊乱以及脾脏T淋巴细胞亚群的变化,而适当剂量的VE对TCDD所致的毒性有拮抗作用。     

十全育真汤对H22荷瘤小鼠免疫功能的影响

目的：研究十全育真汤对荷瘤小鼠免疫功能的影响,探讨十全育真汤抗肿瘤的作用机制。方法：SPF级雄性昆明种小鼠30只,制成荷H₂₂小鼠肝癌细胞移植瘤模型,随机分为模型组、阳性对照组及十全育真汤组（n=10）;另选择未接种小鼠10只为正常对照组。正常对照组、模型组每天按10 ml/kg灌胃生理盐水及蒸馏水,阳性对照组、十全育真汤组每天按8 g/kg、18 g/kg灌胃参一药液（80 mg/ml）与十全育真汤剂。连续给药14 d后处死小鼠,测量胸腺、脾脏指数及抑瘤率,检测外周血中白细胞、淋巴细胞含量及T细胞亚群CD3、CD4、CD8细胞百分比,血清中白细胞介素2（IL-2）、肿瘤坏死因子α（TNF-α）及干扰素-β（IFN-β）的含量,淋巴细胞增殖能力及NK细胞杀伤功能。结果：较正常对照组,十全育真汤组小鼠体重明显增加,脾脏指数显著增大（P<0.05）;白细胞、淋巴细胞CD4、CD8、CD3及TNF-α含量明显升高（P<0.05）;IL-2、IFN-β含量显著下降（P<0.05）;淋巴细胞增殖能力、NK细胞杀伤功能明显升高（P<0.05）。与模型组相比,十全育真汤组小鼠胸腺、脾脏指数显著增大（P<0.05）;白细胞、淋巴细胞CD3、CD4、IL-2、IFN-β及TNF-α含量明显升高（P<0.05）,CD8含量则显著降低（P<0.05）;NK细胞杀伤功能及淋巴细胞增殖能力显著增加（P<0.05）。结论：十全育真汤可促进H₂₂荷瘤小鼠免疫器官的生长,增强机体免疫功能,有利于肿瘤机体的恢复。     

黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏的保护作用

目的探讨黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏的保护作用。方法将40只雄性小鼠随机分成4组,即对照组、苯甲醛染毒组（苯：5 g/m^3,甲醛：50 mg/m^3）、苯甲醛染毒黄芪多糖低剂量保护组[黄芪多糖：10 mg/（kg.d）,苯：5 g/m^3,甲醛：50 mg/m^3]、苯甲醛染毒黄芪多糖高剂量保护组[黄芪多糖：20 mg/（kg.d）,苯：5 g/m^3,甲醛：50 mg/m^3]。采用静式吸入染毒,每天2 h,连续30 d,并同时采用饮水的方式给予黄芪多糖保护。末次染毒24 h内,处死小鼠,对小鼠脾中谷胱甘肽（GSH）含量及谷胱甘肽过氧化物酶（GSH-PX）活性进行测定和分析。结果苯、甲醛染毒黄芪多糖保护各组脾组织中GSH含量和GSH-PX活性均高于苯、甲醛染毒组,均有统计学意义（P〈0.01）而与对照组的差异无统计学意义（P〉0.05）,苯、甲醛染毒黄芪多糖保护组高剂量组脾组织中GSH-PX活性高于低剂量组,差异有统计学意义（P〈0.01）。结论黄芪多糖对暴露于苯、甲醛环境中小鼠脾脏具有保护作用,且对脾中GSH含量的作用有随剂量增加而增大的趋势,对脾中GSH-PX活性的作用随剂量增加而增大。     

大豆多肽Lunasin对类风湿关节炎大鼠T细胞免疫指标的影响

目的：探讨Lunasin对实验性类风湿关节炎（RA）大鼠免疫功能的影响。方法： Wistar雄性大鼠50只,按体重随机分为（n=10）：对照组、模型组和3个Lunasin处理组（0.1,0.2,0.4 mg/kg灌胃）。利用弗氏完全佐剂（FCA）局部注入大鼠足跖皮内,建立RA模型,治疗组Lunasin灌胃每天1次,对照组和模型组灌胃等量生理盐水;于实验第21天,检测足跖厚度、滑膜液T淋巴细胞活化情况和滑液中白介素-12（IL-12）、肿瘤坏死因子β（TNF-β）和I L-4、IL-10的分泌情况。结果：Lunasin可降低T淋巴细胞活化标志物CD69⁺和CD25⁺的表达,减少滑膜液中IL-12、TNF-β的分泌,增加IL-4、IL-10的分泌。结论：Lunasin能够抑制类风湿关节炎滑膜液中T细胞的活化并能反转Th1/Th2型细胞因子的分泌,调节类风湿关节炎免疫微环境。     

口服卡介菌诱导免疫耐受的CD4^＋CD25^＋调节性T细胞机制研究

目的：研究口服卡介菌诱导免疫耐受对CD4^＋CD25^＋调节性T细胞的影响。方法：采用口服MPB制备EAE大鼠模型,随机分为BCG组（0.5mg/kg）和EAE模型组（PBS）,每组各15只,连续经口灌服给药14d,同时选取15只健康大鼠作为对照组。分别于免疫后15d、27d流式细胞术检测外周血、胸腺及脾脏中CD4^＋CD25^＋T淋巴细胞百分率,ELISA检测血清IL-6、TGF-β、IgE、IgG含量。结果：与EAE模型组相比,免疫后BCG组大鼠外周血、胸腺及脾脏中CD4^＋CD25^＋T淋巴细胞百分率增加,血清IL-6、TGF-β含量上升,血清IgE、IgG抗体水平下降。结论：口服BCG通过上调淋巴器官中CD4^＋CD25^＋T淋巴细胞比例,抑制效应性T细胞活性,发挥免疫耐受作用。     

芹菜多糖抑制小鼠肺癌的作用研究*

目的:探讨芹菜多糖抗肺癌的作用及机制。方法:提取纯化芹菜多糖,通过红外光谱和凝胶渗透色谱法对其进行鉴定;每只小鼠腹股沟皮下注射2×10⁷个Lewis肺癌细胞,建立肺癌C57BL/6小鼠模型,随机分为5组,每组10只。两天后,分别0、25、50、75、100 mg/kg芹菜多糖灌胃荷瘤小鼠10 d,流式和qPCR法分析小鼠外周血CD4⁺、CD8⁺淋巴细胞和脾淋巴细胞因子IL-2、IFN-γ与IL-4,并取肿瘤组织拍照和称重。结果:本实验所提取的芹菜多糖纯度为82%,鉴定为不均一的多糖,分子量为1.17×10³ kD;芹菜多糖灌胃小鼠可显著抑制肺癌的生长(P＜0.01),75 mg / kg治疗10 d后,可提高小鼠外周血CD4⁺和CD8⁺淋巴细胞的百分比(P ＜0.01),并明显增加50 mg / kg以上治疗组的脾淋巴细胞IL-2、IFN-γ和IL-4的转录水平(P ＜0.01)。结论:芹菜多糖可通过增强机体免疫,尤其是细胞免疫而发挥抗肺癌的作用。     

EA rosette forming lymphoid cells: distribution as to cell types and organs from chickens of different developmental stages.

The interaction of chicken spleen cells with sheep erythrocytes coated with chicken antibody (EA complexes) was studied using a rosette assay. The results reported in this paper indicate that subpopulations of chicken lymphocytes, monocytes, and heterophils have a receptor for EA. The formation of rosettes between chicken lymphoid cells and sheep erythrocytes (SRBC) was dependent upon the concentration of antibody used to sensitize the SRBC. In a developmental study of rosette-forming lymphocytes (RFL), the bursa was the first site of appearance of large numbers of RFL. The percentage of RFL in the bursa reached a peak at 17 days of embryonic life, and declined to a low by hatching. The percentage of RFL in the spleen, however, began to increase at the time of hatching and by 6 weeks of age the spleen far surpassed the bursa in percentage RFL. At no age were significant numbers of RFL detected in the thymus.     

Ability of chicken B cells from different compartments to respond to TNP-Ficoll

The responsiveness of chicken B cells from various compartments to T-independent antigens was studied by immune transfers of spleen and bursa cells into immunosuppressed recipients. Bursa cells from 8- to 10-wk-old donors failed to respond to trinitrophenylated Ficoll (TNP-F) even when thymus cells or splenic T cells were added. Spleen cells from the same donors transferred responses, as judged both by anti-TNP plaque-forming cells (PFC) per spleen and serum anti-TNP titers. In contrast, responses to TNP-Brucella abortus (TNP-BA) were transferred at least as well as by bursa as by spleen cells. Rabbit anti-chicken T cell serum plus complement treatment of the spleen cells reduced their ability to transfer responses to sheep erythrocytes, but either did not affect or enhanced serum antibody responses to TNP-BA and TNP-F. In intact animals, responsiveness to i.v. injected TNP-F was found to develop slowly after hatching in the chicken. At the age of 2 and 3 mo, PFC/spleen on day 4 after TNP-F injection were only 20% and 40%, respectively, of the adult response. Thymectomy at hatching further delayed this development, resulting in 12% and 45% of the adult control response at ages of 3 and 4 mo. It is concluded that responsiveness to the TI-2 antigen, TNP-F, develops slower than that to the TI-1 antigen, TNP-BA, and is restricted to the splenic B cell compartment. In addition, this development appears to be faster in the presence rather than in the absence of the thymus. In view of the previously shown effect of thymus on bursa development, these data suggest that the maturation of TI-1 antigen (TNP-F)-respondent chicken B cells requires residence in both the bursa and spleen before the development of responsiveness to such antigens.     

The Effect of Selenium and Polysaccharide of Atractylodes macrocephala Koidz. (PAMK) on Immune Response in Chicken Spleen Under Heat Stress

The aim of the present study was to investigate the effect of selenium (Se), polysaccharide of Atractylodes macrocephala Koidz. (PAMK), and the combination of Se and PAMK on the immune response, heat shock protein (HSP) levels under heat stress (HS) condition in chicken spleen. Two hundred chickens were randomly divided into two groups, the HS group and the control (Con) group. Then these chickens were treated with Se (0.3 mg/kg), PAMK (200 mg/kg) alone, and the combination of Se (0.3 mg/kg) and PAMK (200 mg/kg). The antioxidative enzymes, cytokines contents, and expression levels of HSP27 and HSP70 were examined in chicken spleen. The results indicated that HS induced higher levels of TNF-α, IL-4, HSP27, HSP70, and MDA levels but lower level of IFN-γ, IL-2, Gpx, and SOD in spleen (P?<?0.05). These responses were ameliorated by the treatment of Se, PAMK alone, and the combination of Se and PAMK (P?<?0.05 or not) The results showed that under common condition, Se and PAMK could improve the immune response by enhancing the levels of some cytokines to proper levels; however, under HS condition, Se and PAMK could change the abnormal levels of cytokines and oxidative damages to ameliorate the injury induced by HS. In addition, there existed synergistic effect on the modulation of these biomarkers in chicken spleen between Se and PAMK. So both Se and PAMK play important roles in regulating the immune function in chicken. Considering the synergistic effect on immune regulation of PAMK, this herb deserves further investigation to evaluate its role in improving the effect of traditional immune regulators.     

The influence of chlortetracycline on the immunological reactivity of chickens

Morphological examination of spleen and bursa of Fabricius of chickens fed on a diet without or with the addition of chlortetracycline (50, 100 and 200 CTC mg/kg) has shown that both low and high doses of antibiotic in the diet do not influence significantly the structure and reactivity of the lymphatic tissue following the antigenic stimulation. Certain differences were found in the number of lymphatic follicles in the spleen between control and experimental animals which received the highest dose 200 mg CTC/kg but even the greatest differences found on the fifth day after vaccination were not significant (P<0.1). On the other hand, the study of the level of agglutinin titres in the blood of control and experimental broilers has shown that the doses 100 and 200 mg CTC/kg in the diet have significantly influenced their production. After such doses the latent period was slightly lenghtened and both the highest and the average titres were lowered during the whole postvaccinal period to a degree which correlated the magnitude of dosage of the antibiotic.     

O antigen-dependent mutant of bacteriophage T5.

The administration of cyclophosphamide (50 to 100 mg/kg) at 48 to 72 h before removal of murine lung or spleen mononuclear cells for culture rendered DBA/2 mice incapable of generating an effective cytotoxic T-lymphocyte response to influenza A virus-infected cells. The cytotoxic T-lymphocyte precursor frequency to influenza A virus in lung and spleen cells from cyclophosphamide-treated mice was significantly decreased when compared with that of normal littermate controls. The low cytotoxic T-lymphocyte activity in the lungs and spleens of cyclophosphamide-treated mice could be partially restored in vitro by human interleukin 2.     

Prediction of Selenoprotein T Structure and Its Response to Selenium Deficiency in Chicken Immune Organs

Selenoprotein T (SelT) is associated with the regulation of calcium homeostasis and neuroendocrine secretion. SelT can also change cell adhesion and is involved in redox regulation and cell fixation. However, the structure and function of chicken SelT and its response to selenium (Se) remains unclear. In the present study, 150 1-day-old chickens were randomly divided into a low Se group (L group, fed a Se-deficient diet containing 0.020 mg/kg Se) and a control group (C group, fed a diet containing sodium selenite at 0.2 mg/kg Se). The immune organs (spleen, thymus, and bursa of Fabricius) were collected at 15, 25, 35, 45, and 55 days of age. We performed a sequence analysis and predicted the structure and function of SelT. We also investigated the effects of Se deficiency on the expression of SelT, selenophosphate synthetase-1 (SPS1), and selenocysteine synthase (SecS) using RT-PCR and the oxidative stress in the chicken immune organs. The data showed that the coding sequence (CDS) and deduced amino acid sequence of SelT were highly similar to those of 17 other animals. Se deficiency induced lower (P?<?0.05) levels of SelT, SPS1, and SecS, reduced the catalase (CAT) activity, and increased the levels of hydrogen peroxide (H₂O₂) and hydroxyl radical (–OH) in immune organs. In conclusion, the CDS and deduced amino acid sequence of chicken SelT are highly homologous to those of various mammals. The redox function and response to the Se deficiency of chicken SelT may be conserved. A Se-deficient diet led to a decrease in SelT, SecS, and SPS1 and induced oxidative stress in the chicken immune organs. To our knowledge, this is the first report of predictions of chicken SelT structure and function. The present study demonstrated the relationship between the selenoprotein synthases (SPS1, SecS) and SelT expression in the chicken immune organs and further confirmed oxidative stress caused by Se deficiency. Thus, the information presented in this study is helpful to understand chicken SelT structure and function. Meanwhile, the present research also confirmed the negative effects of Se deficiency on chicken immune organs.     

Dietary supplementation of organic or inorganic chromium modulates the immune responses of broilers vaccinated with Avian Influenza virus vaccine

Dietary supplementation with the organic chromium (Cr) has been shown to positively affect the immune function of poultry. However, to our knowledge, no experiment has been done to directly compare the impacts of Cr chloride and chromium picolinate (CrPic) on the immune responses of broilers vaccinated with Avian Influenza (AI) virus vaccine. Therefore, the present experiment was conducted to investigate the effects of supplemental Cr sources (Cr chloride and CrPic) and levels on the growth performance and immune responses of broilers vaccinated with AI virus vaccine so as to provide an effective nutritional strategy for improving immune function of broilers. A total of 432 1-day (d)-old male broiler chicks were used in a 1 plus 2×4 design. Chickens were given either a diet without Cr supplementation (control) or diets supplemented with 0.4, 0.8, 1.6, or 3.2 mg Cr/kg as either Cr chloride or CrPic for 42 d. Compared to the control, dietary Cr supplementation had no effect (P>0.05) on average daily gain, average daily feed intake and gain : feed of broilers during the starter and grower phases, but increased (P<0.05) the relative weights of bursa of fabricius on d 21 and thymus, spleen, or bursa of fabricius on d 42, serum antibody titers against AI virus on d 21, 28, 35 and 42, blood T-lymphocyte transformation rate on d 28 and 42, blood T-lymphocyte percentage on d 42, and serum interleukin-2 contents on d 28. Broilers fed the diets supplemented with the inorganic Cr chloride had higher (P<0.05) weights of thymus, spleen and bursa of fabricius than those fed the diets supplemented with the CrPic on d 42. In addition, broilers fed the diets supplemented with the CrPic had higher (P<0.05) antibody titers against AI virus than those fed the diets supplemented with the inorganic Cr chloride on d 21 and 35. These results indicate that dietary Cr supplementation improved immune responses of broilers vaccinated with AI virus, and the inorganic Cr chloride was more effective than the CrPic in increasing the relative weights of lymphoid organs, however, the CrPic was more effective than the inorganic Cr chloride in enhancing the serum antibody titer against AI virus.     

Chicken fetal antigen: association with lymphoid development and differentiation

Rabbit antisera capable of detecting chicken fetal antigen (CFA) was prepared against 1-day chick red blood cells (RBCs) and made specific by exhaustive adsorption with adult chicken peripheral RBCs (PRBCs) from the same strain. Microcytotoxicity was used to study the incidence of CFA on lymphocytes obtained from several organs at different developmental stages in the chicken. Lymphocyte-associated CFA (LA-CFA) determinants and erythrocyte-specific CFA (ES-CFA) determinants were distinguished through the use of adsorption analysis. The high incidence of CFA-positive lymphocytes found in the fetal bursa and thymus was not equaled in the peripheral organs of the spleen, cecal tonsils, and gland of Harder. CFA expression on adult lymphocytes was restricted to the thymus and peripheral blood. It is suggested that these cells may represent a subpopulation of T lymphocytes. Adult spleen, cecal tonsils, and gland of Harder were virtually devoid of CFA-bearing lymphocytes. At fetal developmental stages when greater than 94% of the bursal B cells were CFA-positive, few, if any, of the highly differentiated Harderian B cells possessed CFA. It is suggested that LA-CFA expression is dependent upon B cell differentiation and/or the bursa (central) vs gland of Harder (peripheral) microenvironment. The pattern of CFA expression on bursacytes is discussed in light of the properties of age resistance and bursal-dependent target cells associated with virally induced lymphoid leukosis.     

B-L antigens (Class II) of the chicken major histocompatibility complex control T-B cell interaction

The detailed study of the genetic control of T-B cell interactions in the chicken has been hampered by the lack of defined major histocompatibility complex (MHC) recombinant chicken lines. In the present study we have used some recently described MHC recombinant chicken lines separating regions encoding antigens that are homologous to class I and class II antigens of mammals in adoptive bursa cell transfer experiments, in which bursa cells from newly hatched chicks were transplanted into cyclophosphamide (Cy)-treated chicks. Subsequent immunizations of the recipients with a thymus-dependent antigen (SRBC) and a thymus-independent antigen (Brucella abortus) showed that the generation of germinal centers in the spleen and the production of antibodies to SRBC required identity between donor and recipient class II antigens (B-L antigens), whereas response to Brucella antigen did not require identity at any of the known MHC loci of the chicken. The results thus reveal that also in the chicken class II (B-L) region genes encode cell-surface glycoproteins that serve as restriction elements in T-B cell cooperation.This work has been presented in part at the Ninth International Congress of the Transplantation Society (Vainio et al. 1983a).