Merica R, Khoruts A, Pape K A, Reinhardt R L, Jenkins M K
Department of Microbiology and Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
J Immunol. 2000 May 1;164(9):4551-7. doi: 10.4049/jimmunol.164.9.4551.
It is thought that protective immunity is mediated in part by Ag-experienced T cells that respond more quickly and vigorously than naive T cells. Using adoptive transfer of OVA-specific CD4 T cells from TCR transgenic mice as a model system, we show that Ag-experienced CD4 T cells accumulate in lymph nodes more rapidly than naive T cells after in vivo challenge with Ag. However, the magnitude of clonal expansion by Ag-experienced T cells was much less than that of naive T cells, particularly at early times after primary immunization. Ag-experienced CD4 T cells quickly reverted to the slower but more robust clonal expansion behavior of naive T cells after transfer into a naive environment. Conversely, the capacity for rapid clonal expansion was acquired by naive CD4 T cells after transfer into passively immunized recipients. These results indicate that rapid in vivo response by Ag-experienced T cells is facilitated by Ag-specific Abs, whereas the limited capacity for clonal expansion is imposed by some other factor in the immune environment, perhaps residual Ag.
据认为，保护性免疫部分是由经历过抗原的T细胞介导的，这些T细胞比初始T细胞反应更快、更强烈。我们使用来自TCR转基因小鼠的OVA特异性CD4 T细胞的过继转移作为模型系统，发现在体内用抗原攻击后，经历过抗原的CD4 T细胞比初始T细胞更快地在淋巴结中积累。然而，经历过抗原的T细胞的克隆扩增幅度远小于初始T细胞，特别是在初次免疫后的早期。经历过抗原的CD4 T细胞在转移到初始环境后，很快恢复到初始T细胞较慢但更稳健的克隆扩增行为。相反，初始CD4 T细胞在转移到被动免疫的受体后获得了快速克隆扩增的能力。这些结果表明，经历过抗原的T细胞在体内的快速反应由抗原特异性抗体促进，而克隆扩增能力的限制是由免疫环境中的其他因素造成的，可能是残留抗原。
