Bottomly K, Mosier D E
J Exp Med. 1981 Aug 1;154(2):411-21. doi: 10.1084/jem.154.2.411.
Two synergizing antigen-specific helper T (Th) cell populations are required for an optimal TEPC15 (T15)-dominated antiphosphorylcholine (PC) plaque- forming cell response . In these studies, the two Th cell sets are shown to differ in their requirements for recognition of self-major histocompatibility complex (MHC)-encoded determinants by testing the ability of Th cells from F(1) {arrow} parent bone marrow chimeras to collaborate with PC-specific B cells bearing MHC-encoded determinants of either parental haplotypes. Previous studies have shown that one antigen-specific Th cell population is required for T-dependent anti-PC responses and activates PC-specific B cells only if the hapten, PC, is physically linked to the priming antigen. This Th cell, referred to as ThMHC, induces anti-PC responses that are mainly non-T15 in character, and it appears to be identical to the conventional antigen- specific Th cell. In these experiments, using T cells from (A X B)F(1) {arrow} parent A chimeras, ThMHC cells requiring hapten-carrier association provide help for F(1) and parent A B cells but not for B cells from parent B, thus confirming that the activity of the conventional Th cell is H-2 restricted . The second antigen-specific Th cell population, whose function is measured in the presence of the ThMHC cell set, preferentially activates T15-bearing B cells. This Th cell set (ThId) is missing in mice expressing low levels of T15-bearing antibody and can be restored by the addition of antigen-specific T cells from donors expressing high levels of circulating T15 Id. These studies demonstrate that T cells from F(1) {arrow} parent chimeras that express substantial levels of T15-bearing anti-PC antibody could provide ThId cell activity for the selective activation of T15-bearing B cells of F(1) and both parental H-2 types. These results imply that whereas the activity of conventional, ThMHC, cells is clearly H-2 restricted, ThId cells from the same chimeric donors are not required to recognize antigen in association with self-MHC-encoded determinants for successful T-B collaboration .
为了获得最佳的以TEPC15（T15）为主导的抗磷酸胆碱（PC）斑块形成细胞反应，需要两个协同作用的抗原特异性辅助性T（Th）细胞群体。在这些研究中，通过测试来自F(1)→亲代骨髓嵌合体的Th细胞与携带任一亲代单倍型MHC编码决定簇的PC特异性B细胞协作的能力，显示这两个Th细胞群体在识别自身主要组织相容性复合体（MHC）编码决定簇的需求上存在差异。先前的研究表明，T细胞依赖性抗PC反应需要一个抗原特异性Th细胞群体，并且只有当半抗原PC与引发抗原物理连接时，该群体才能激活PC特异性B细胞。这种Th细胞被称为ThMHC，它诱导的抗PC反应主要是非T15性质的，并且似乎与传统的抗原特异性Th细胞相同。在这些实验中，使用来自（A×B）F(1)→亲代A嵌合体的T细胞，需要半抗原-载体关联的ThMHC细胞为F(1)和亲代A的B细胞提供帮助，但不能为亲代B的B细胞提供帮助，从而证实传统Th细胞的活性受H-2限制。第二个抗原特异性Th细胞群体，其功能在ThMHC细胞群体存在的情况下进行测量，优先激活携带T15的B细胞。在表达低水平携带T15抗体的小鼠中缺失这种Th细胞群体（ThId），并且可以通过添加来自表达高水平循环T15 Id的供体的抗原特异性T细胞来恢复。这些研究表明，来自F(1)→亲代嵌合体且表达大量携带T15的抗PC抗体的T细胞可以为选择性激活F(1)和亲代两种H-2类型的携带T15的B细胞提供ThId细胞活性。这些结果意味着，虽然传统的ThMHC细胞的活性明显受H-2限制，但来自相同嵌合供体的ThId细胞在成功的T-B协作中不需要与自身MHC编码决定簇关联来识别抗原。
