Merchant B, Inman J K
J Exp Med. 1977 Feb 1;145(2):372-89. doi: 10.1084/jem.145.2.372.
Immunization of rabbits or mice with a single, chemically defined hapten elicits populations of plaque-forming cells (PFC) detectable not only on sheep erythrocytes (SRBC) bearing the immunizing hapten, but also on SRBC bearing structural analogues of the immunizing hapten. Most of these analogue-reactive PFC preferentially lyse analogue-conjugated SRBC and cannot be detected on erythrocytes bearing the immunizing hapten. Thus, they represent heretofore largely unstudied components of the secretory B-cell response to haptenic immunization, and they have been termed alloreactive PFC. Such alloreactive PFC are detectable using either classical small haptens or tripeptide-enlarged counterparts of these classical haptens. They are present in large numbers both in direct and in indirect PFC assays, and they are elicited in response to both thymic-dependent and thymic-independent antigens. Relatively few alloreactive PFC can be attributed to cells producing hapten-carrier or "bridge area"-specific antibodies. Since the antibodies released by alloreactive PFC can also be detected by passive hemagglutination, their presence does not appear attributable to vagaries of complement activation. Numerous coexisting alloreactive PFC populations are detectable after haptenic immunization. In early direct PFC responses it is not nucommon for a single alloreactive PFC population to outnumber the population of PFC detectable on SRBC bearing the actual immunizing hapten. These alloreactive PFC may be the source of at least some of the new "nonspecific" Ig which is formed at the time of immunization but about which little is known for lack of available techniques. Some possible implications of these findings on the specificity of B precursor cell activation are discussed.
用单一的、化学结构明确的半抗原免疫兔或小鼠，可引发斑块形成细胞（PFC）群体，这些细胞不仅能在携带免疫半抗原的绵羊红细胞（SRBC）上被检测到，也能在携带免疫半抗原结构类似物的SRBC上被检测到。这些与类似物反应的PFC中的大多数优先裂解与类似物结合的SRBC，而在携带免疫半抗原的红细胞上无法检测到。因此，它们代表了迄今为止在对半抗原免疫的分泌性B细胞反应中很大程度上未被研究的成分，并且它们被称为同种反应性PFC。使用经典的小分子半抗原或这些经典半抗原的三肽扩展类似物均可检测到这种同种反应性PFC。它们在直接和间接PFC检测中均大量存在，并且对胸腺依赖性和胸腺非依赖性抗原均有反应。相对较少的同种反应性PFC可归因于产生半抗原载体或“桥接区域”特异性抗体的细胞。由于同种反应性PFC释放的抗体也可通过被动血凝反应检测到，因此它们的存在似乎并非归因于补体激活的变幻莫测。在半抗原免疫后可检测到大量共存的同种反应性PFC群体。在早期直接PFC反应中，单个同种反应性PFC群体的数量超过在携带实际免疫半抗原的SRBC上可检测到的PFC群体的数量并不罕见。这些同种反应性PFC可能是免疫时形成的至少一些新 的“非特异性”Ig的来源，但由于缺乏可用技术，对此知之甚少。本文讨论了这些发现对B前体细胞激活特异性的一些可能影响。
