Ciavarra R P
Department of Microbiology and Immunology, Eastern Virginia Medical School, Norfolk 23501.
Cell Immunol. 1990 Feb;125(2):363-79. doi: 10.1016/0008-8749(90)90091-5.
I have compared the requirements for T helper (Th) cell function during the generation of virus-specific and alloreactive cytotoxic thymus (T)-derived lymphocyte (CTL) responses. Restimulation of vesicular stomatitis virus (VSV)-immune T cells (VSV memory CTLs) with VSV-infected stimulators resulted in the generation of class I-restricted, VSV-specific CTLs. Progression of VSV memory CTLs (Lyt-1-2+) into VSV-specific CTLs required inductive signals derived from VSV-induced, Lyt-1+2- Th cells because: (i) cultures depleted by negative selection of Lyt-1+ T cells failed to generate CTLs; (ii) titration of VSV memory CTLs into a limiting dilution (LD) microculture system depleted of Th cells generated curves which were not consistent with a single limiting cell type; (iii) LD analysis of VSV memory CTLs did produce single-hit curves in the presence of Lyt-1+2- T cells sensitized against VSV; and (iv) monoclonal anti-L3T4 antibody completely abrogated CTL generation against VSV. Similar results were also obtained with Sendai virus (SV), a member of the paramyxovirus family. The notion that a class II-restricted, L3T4+ Th cell plays an obligatory role in the generation of CTLs against these viruses is also supported by the observation that purified T cell lymphoblasts (class II antigen negative) failed to function as antigen-presenting cells for CTL responses against VSV and SV. T cell lymphoblasts were efficiently lysed by class I-restricted, anti-VSV and -SV CTLs, indicating that activated T cells expressed the appropriate viral peptides for CTL recognition. Furthermore, heterogeneity in the VSV-induced Th cell population was detected by LD analysis, suggesting that at least two types of Th cells were required for the generation of an anti-VSV CTL response. VSV-induced Th cell function could not simply be replaced by exogenous IL-2 because this lymphokine induced cytotoxic cells that had the characteristics of lymphokine-activated killer (LAK) cells and not anti-viral CTLs. In contrast, CTL responses against allogeneic determinants could not be completely blocked with antibodies against L3T4 and depletion of L3T4+ cells did not prevent the generation of alloreactive CTLs in cultures stimulated with allogeneic spleen cells or activated T cell lymphoblasts. Thus, these studies demonstrate an obligatory requirement for an L3T4-dependent Th cell pathway for CTL responses against viruses such as VSV and SV; whereas, CTL responses against allogeneic determinants can utilize an L3T4-independent pathway.
我比较了在病毒特异性和同种异体反应性细胞毒性胸腺（T）衍生淋巴细胞（CTL）反应产生过程中辅助性T（Th）细胞功能的要求。用感染水泡性口炎病毒（VSV）的刺激物对VSV免疫的T细胞（VSV记忆CTL）进行再刺激，导致产生I类限制性、VSV特异性CTL。VSV记忆CTL（Lyt-1-2+）向VSV特异性CTL的进展需要来自VSV诱导的Lyt-1+2-Th细胞的诱导信号，原因如下：（i）通过对Lyt-1+T细胞进行阴性选择而耗尽的培养物未能产生CTL；（ii）将VSV记忆CTL滴定到耗尽Th细胞的有限稀释（LD）微培养系统中产生的曲线与单一限制性细胞类型不一致；（iii）在存在针对VSV致敏的Lyt-1+2-T细胞的情况下，对VSV记忆CTL进行LD分析确实产生了单次打击曲线；（iv）单克隆抗L3T4抗体完全消除了针对VSV的CTL产生。用副粘病毒家族成员仙台病毒（SV）也获得了类似结果。纯化的T细胞淋巴母细胞（II类抗原阴性）不能作为针对VSV和SV的CTL反应的抗原呈递细胞，这一观察结果也支持了II类限制性、L3T4+Th细胞在针对这些病毒的CTL产生中起必要作用的观点。T细胞淋巴母细胞被I类限制性、抗VSV和抗SV CTL有效裂解，表明活化的T细胞表达了适合CTL识别的病毒肽。此外，通过LD分析检测到VSV诱导的Th细胞群体存在异质性，提示产生抗VSV CTL反应至少需要两种类型的Th细胞。VSV诱导的Th细胞功能不能简单地被外源性IL-2替代，因为这种淋巴因子诱导的细胞毒性细胞具有淋巴因子激活的杀伤（LAK）细胞的特征，而不是抗病毒CTL。相比之下，针对同种异体决定簇的CTL反应不能被抗L3T4抗体完全阻断，并且耗尽L3T4+细胞并不能阻止在用同种异体脾细胞或活化的T细胞淋巴母细胞刺激的培养物中产生同种异体反应性CTL。因此，这些研究表明，针对VSV和SV等病毒的CTL反应对依赖L3T4的Th细胞途径有强制性要求；而针对同种异体决定簇的CTL反应可以利用不依赖L3T4的途径。
