Enzyme-linked immunosorbent assay for Giardia-specific IgA in mouse intestinal secretions

We describe an ELISA for trophozoite-specific IgA in the intestinal secretions of mice infected with Giardia muris. Using this method, trophozoite-specific IgA was demonstrated in intestinal secretions of Giardia-infected immunocompetent BALB/c mice. Such antibody was undetectable in the intestinal secretions of Giardia-infected athymic (nude) mice. Immunocompetent BALB/c mice are able to clear G. muris infection whereas nude mice are not. The study provides evidence that the chronicity of G. muris infection in nude mice results from lack of intestinal trophozoite-specific IgA in these animals. By means of the ELISA, trophozoite-specific IgA was demonstrated in intestinal secretions from immunocompetent mice in the absence of protease inhibitors.     

Protective immunity to malaria: studies with cloned lines of Plasmodium chabaudi chabaudi in CBA/Ca mice. III. Protective and suppressive responses induced by immunization with purified antigens

The protective effect of affinity purified antigen has been investigated in an experimental model for malaria which shows a well marked recrudescence of parasitaemia, a feature of the disease in man. A monoclonal antibody (MoAb) recognizing an epitope common to two genetically distinct cloned lines of Plasmodium chabaudi (AS and CB), was used to purify a Mr250,000 polymorphic schizont antigen (PSA) from these parasites. The purified preparations were then examined for the presence of specific and cross-reactive epitopes by immunoprecipitation with a panel of MoAb raised against P. chabaudi AS. When tested previously on smears of parasitized blood by immunofluorescence, or against lysates of parasitized erythrocytes by immunoprecipitation, most of these MoAb had been found to be AS specific. When either AS or CB affinity purified Mr250,000 PSA was used as the target, these same MoAb immunoprecipitated both antigens, and in some cases, a number of associated polypeptides (AP) which copurify with the Mr250,000 PSA. Subsequently, mice were immunized with either the purified AS or CB antigens in Freund's complete adjuvant (FCA). Prechallenge sera were compared by indirect immunofluorescence and immunoprecipitation. Sera from mice immunized with AS antigen reacted strongly with AS and cross-reacted with CB parasite preparations. Pre-challenge serum from CB antigen immunized mice reacted well with CB, but only faintly with AS preparations. In mice immunized with the AS antigen and then challenged with either AS or CB parasites, the initial parasitaemias were delayed in appearance and the height of the peak parasitaemia reduced, an effect which was most pronounced after challenge with homologous parasites. Only homologous challenge of the mice immunized with CB antigen produced statistically significant modification of the initial parasitaemia. In the immunized mice challenged with homologous parasites, the delayed appearance and slightly reduced peak of the primary parasitaemia was associated with delayed resolution of the patent parasitaemia and significant enhancement of the recrudescence.     

C_3基因在BXSB小鼠主要脏器中的表达

用同位素标记ｃＤＮＡ探针的分子杂交方法检测了ＢＸＳＢ小鼠肝、肾、脾、胸腺各脏器中补体Ｃ_３ｍＲＮＡ的表达情况，结果表明３～４月龄雄性ＢＸＳＢ小鼠肝、肾、脾各脏器Ｃ_３ｍＲＮＡ的表达量较正常对照鼠显著增加。Ｃ_３基因的过度表达可能参与ＢＸＳＢ小鼠ＳＬＥ多脏器非感染性炎症的发生，同时提示该鼠存在Ｍ系统的大量扩增及活化。     

江西麦饭石对某些实验动物生理功能影响

用江西麦饭石水浸液喂养小鼠116只,自来水喂养39只,食物条件完全相同,一个月后,发现饮用江西麦饭石水浸液的小鼠体重增长和抗疲劳及耐缺氧能力均优于对照组。用麦饭石任氏液灌注离体蛙心后,心肌收缩力有明显增强。     

Response of V beta 8.1+ T cell clones to self Mls-1a: implications for the origin of autoreactive T cells.

Clonal deletion and anergy are two major mechanisms of self-tolerance. However, the molecular mechanisms underlying clonal deletion and anergy, as well as the threshold of TCR affinity/avidity required for these processes, are not known. Expression of the V beta 8.1 TCR correlates with the reactivity of the T cells to the minor lymphocyte stimulating locus-1a (Mls-1a) and T cells expressing this TCR are deleted in the thymus of Mls-1a mice. Similarly, in TCR V beta 8.1 transgenic mice, the number of CD4+CD8-T cells is reduced in Mls-1a mice. However, small numbers of CD4+CD8-T cells remain in the periphery of adult Mls-1a transgenic mice. We have generated T cell clones from TCR V beta 8.1 transgenic mice by stimulation of lymph node T cells with C57BL/6 alloantigens. Interestingly, CD4+CD8-V beta 8.1+ clones isolated from the transgenic mice of Mls-1a background responded to the self-antigen Mls-1a, to which they did not respond in primary assay. Reactive patterns of the clones were compared with clones derived from Mls-1b mice. Proliferation and cytokine production of the clones from Mls-1a mice to the self-antigen Mls-1a were generally reduced when compared with clones from Mls-1b mice. More importantly, T cell clones from Mls-1a mice required more Mls-1a antigen for their activation, and were more susceptible to the inhibitory effects of anti-CD4 antibody on the proliferative responses to Mls-1a than those from Mls-1b mice. These results suggest that the T cell receptor on clones derived from Mls-1a mice have functional but reduced affinity/avidity for self-antigen Mls-1a.     

rhIL－1α对小鼠骨髓细胞长周期培养中造血细胞增殖的影响

应用小鼠骨髓细胞长周期培养（ＬＴＢＭＣ）体系，观察重组人白细胞介素－１α（ｒｈＩＬ－１α）对造血细胞增殖的影响。结果显示，经ｒｈｌＬ－１α作用后，小鼠ＬＴＢＭＣ中悬浮细胞数增多，其中粒单系祖细胞（ＣＦＵ－ＧＭ）数量也明显增加，维持时间延长。表明ｒｈＩＬ－１α能促进小鼠造血细胞在体外ＬＴＢＭＣ中增殖并分化，而且与剂量有关系。ｒｈＩＬ－１α加入的时间，以骨髓细胞２次接种时同时加入为好，延迟加入则作用减弱。本实验对骨髓干、祖细胞体外扩增和自体骨髓移植等方面的研究有一定意义。     

ICR 小白鼠脏器中铜,锌锰含量

对40只正常成年远交系 ICR 小白鼠的主要脏器,用 WFX—Ⅱ型双光束原子吸收分光光度计测定了各脏器中铜、锌、锰含量.结果表明,主要脏器中铜、锌、锰含量大小顺序不一,铜含量最多的脏器是心,锌、锰含量最多的脏器是肝,在雌雄之间均无显著性差异.     

25％乙基硫环磷农药的诱变性研究

本文对新型有机磷农药，２５％乙基硫环磷进行了Ａｍｅｓ及微核两项诱变性试验研究。Ａｍｅｓ试验中，无论是否加入Ｓ９活化系统，２５％乙基硫环磷均未能诱发回变菌落数的增加；微核试验的各剂量组ＰＣＥ微核率也较低，（２‰～３‰），与阴性对照相比无显著性差异。     

急性苯中毒对小鼠末梢血象和骨髓细胞构成的影响

取３２只２～３个月的ＢＡＬＢ／Ｃ小白鼠，随机分为４组，每组８只，第１组为对照组，其余３个组为实验组，实验组小白鼠左腿皮下注射苯０．３ｍｌ（１５ｍｌ／ｋｇ体重）．注射后分别于２４ｈ，４８ｈ，７２ｈ脱颈处死。观察中毒前、后末梢血象、骨髓细胞、骨髓细胞构成的变化。结果表明，苯中毒时骨髓变化先于末梢血象的变化，骨髓的病变为造血细胞变性、坏死，大量毛细血管扩张、充血，骨髓细胞构成降低，而且骨髓细胞构成中细胞成分降低早于外周血粒细胞减少。