Richter M, Behelak Y
Pathol Microbiol (Basel). 1975;42(2):73-91.
Attempts were made to initiate the primary and secondary humoral immune responses to sheep red blood cells (SRBC) in vitro as determined by the hemolytic plaque-forming cell (PFC) response, with cell suspensions prepared from a variety of lymphoid organs of the rabbit- thymus, bone marrow, spleen, appendix, sacculus rotundus, Peyer's patches, popliteal lymph node and circulating leukocytes. A number of different media and gaseous phases were utilized in order to establish the optimal conditions for the immune response in vitro. The induction of a secondary PFC response was consistently obtained with 'memory' spleen cells obtained from rabbits 3-6 months following intravenous immunization with SRBC but not with cells of any of the other lymphoid organs, and this response probably represents the activity of memory cells which reside in the rabbit spleen. A primary response was observed only with 'normal' spleen cells, and the medium which faciliated the response was different from that which facilitated the induction of the secondary response in vitro. It was also observed, using a medium in which normal spleen cells were incapable of generating PFC', that mixed cultures of normal spleen and normal appendix or bone marrow cells could give a marked PFC reponse in vitro. Whether the PFC response to SRBCs obtained with the lymphoid cells of normal, unimmunized rabbits represent a true primary response, a secondary response, or a response of a different nature as a consequence of continuous subthreshold immunization of the rabbit with enteric microorganisms which cross-react with the antigen, remains to be determined. However, out initial successes with cultures consisting of cells of at least two distinct lymphoid organs in cases where the cells of any one of these organs could not respond, suggest that interaction of at least two functionally distinct cells is required and that the repsonse observed in vitro is probably a primary immune response.
通过溶血空斑形成细胞（PFC）反应来测定，尝试在体外引发对绵羊红细胞（SRBC）的初次和二次体液免疫反应，所用细胞悬液取自兔的多种淋巴器官——胸腺、骨髓、脾脏、阑尾、圆小囊、派伊尔结、腘淋巴结和循环白细胞。使用了多种不同的培养基和气态环境，以确立体外免疫反应的最佳条件。用静脉注射SRBC后3 - 6个月的兔的“记忆”脾细胞，始终能诱导出二次PFC反应，但其他淋巴器官的细胞则不能，这种反应可能代表了存在于兔脾脏中的记忆细胞的活性。仅用“正常”脾细胞观察到了初次反应，且促进该反应的培养基与促进体外二次反应诱导的培养基不同。还观察到，在一种正常脾细胞无法产生PFC的培养基中，正常脾细胞与正常阑尾或骨髓细胞的混合培养物在体外可产生显著的PFC反应。正常、未免疫兔的淋巴细胞对SRBC产生的PFC反应，究竟代表真正的初次反应、二次反应，还是由于兔被与该抗原发生交叉反应的肠道微生物持续进行亚阈值免疫而产生的不同性质的反应，仍有待确定。然而，在任何一个器官的细胞无反应的情况下，我们最初使用至少由两个不同淋巴器官的细胞组成的培养物取得了成功，这表明至少需要两种功能不同的细胞相互作用，且体外观察到的反应可能是一种初次免疫反应。
