Ramseier H, Lindenmann J
Exp Cell Biol. 1977;45(1-2):60-88. doi: 10.1159/000162858.
A product of antigenic recognition (PAR) was produced whenever receptors for alloantigens from T lymphocytes or a principle present in T-cell dependent alloantisera interacted with alloantigen. With two forms of the PAR assay (direct and indirect) the mechanisms underlying these interactions have been analyzed. For the interaction of T-lymphocyte receptors with alloantigen measured with direct PAR assays, the following conclusion emerged: upon confrontation with alloantigen, receptors (if not already present in secreted form) had first to be released from T-cell membranes. Shed T-cell receptors interacted with alloantigens by solubilizing them. Both processes could be prevented by fixing cells with formaldehyde. Release of T-cell receptors was temperature-dependent, solubilization of alloantigens was not. Because in mixed cell cultures receptors had first to be shed, this process was considerably slower and, in concordance with temperature dependence of receptor release, took place only at 37 degrees C. Titration of T lymphocytes with 'bound' receptors by the direct PAR test revealed that in the presence of excess alloantigen 10(2) T cells sufficed to give measurable responses. Supernates of parental strain lymphocytes containing numerous T-cell receptor specificities could be depleted of one of them. Alloantisera raised in presence of T helper cells ('T alloantisera') contained a principle capable of recognizing alloantigens, alloantisera incited in the absence of T helpers ('B alloantisera') did not. The recognizing principle appeared to be IgG. Like T-cell receptors, it was capable of solubilizing alloantigens form target cell membranes. B alloantisera lacked this capacity and their alloantigen-recognizing moiety was found to be monomeric IgM. The mode of interaction of this IgM with alloantigen most likely consisted in fixation to and shielding of antigen.
每当T淋巴细胞的同种异体抗原受体或T细胞依赖性同种异体抗血清中存在的一种物质与同种异体抗原相互作用时，就会产生抗原识别产物（PAR）。通过两种形式的PAR检测（直接法和间接法），对这些相互作用的潜在机制进行了分析。对于用直接PAR检测法测量的T淋巴细胞受体与同种异体抗原的相互作用，得出了以下结论：在与同种异体抗原接触时，受体（如果尚未以分泌形式存在）首先必须从T细胞膜上释放出来。脱落的T细胞受体通过溶解同种异体抗原来与之相互作用。这两个过程都可以通过用甲醛固定细胞来阻止。T细胞受体的释放依赖于温度，而同种异体抗原的溶解则不依赖温度。因为在混合细胞培养中，受体首先必须脱落，所以这个过程相当缓慢，并且与受体释放的温度依赖性一致，只在37℃时发生。通过直接PAR检测用“结合”受体对T淋巴细胞进行滴定显示，在存在过量同种异体抗原的情况下，10²个T细胞足以产生可测量的反应。含有多种T细胞受体特异性的亲代菌株淋巴细胞的上清液可以去除其中一种特异性。在T辅助细胞存在下产生的同种异体抗血清（“T同种异体抗血清”）含有一种能够识别同种异体抗原的物质，在没有T辅助细胞的情况下产生的同种异体抗血清（“B同种异体抗血清”）则没有。这种识别物质似乎是IgG。与T细胞受体一样，它能够从靶细胞膜上溶解同种异体抗原。B同种异体抗血清缺乏这种能力，并且发现它们的同种异体抗原识别部分是单体IgM。这种IgM与同种异体抗原的相互作用方式很可能是固定并屏蔽抗原。
