Wong G H, Clark-Lewis I, McKimm-Breschkin J L, Schrader J W
Proc Natl Acad Sci U S A. 1982 Nov;79(22):6989-93. doi: 10.1073/pnas.79.22.6989.
Persisting (P) cells (murine cells that resemble mast cells and grow continuously in vitro for prolonged periods in the presence of a specific growth factor) did not express detectable levels of Ia antigens (murine class II major histocompatibility antigens) when their growth was supported by partially purified P cell-stimulating factor. However, when these Ia-negative P cells were transferred to medium conditioned by concanavalin A-stimulated spleen cells, Ia antigens appeared within 24 hr. The increase in Ia antigens was due to induction of synthesis of Ia antigens by P cells and not to absorption of Ia antigens from the conditioned medium or selective growth of Ia-positive cells from a low number of Ia-positive cells in the original population. The Ia-inducing activity was also found in supernatants from antigen-stimulated cloned T-cell lines, but not from certain T-cell hybridomas or the T lymphoma EL-4. The presence of Ia-inducing activity correlated with the presence of interferon-gamma (IFN-gamma). The gel filtration profiles of IFN-gamma activity and Ia-inducing activity were coincident and corresponded to an apparent molecular weight of 40,000-45,000. Both the IFN-gamma and Ia-inducing activity were destroyed by treatment at pH 2. These results indicate that IFN-gamma or a closely related molecule induces Ia antigens on P cells and suggest that regulation of Ia antigen expression may be an important aspect of the effects of IFN-gamma on the immune and hemopoietic systems.
持续存在的（P）细胞（一种鼠细胞，类似于肥大细胞，在特定生长因子存在的情况下可在体外长时间持续生长）在部分纯化的P细胞刺激因子支持其生长时，未表达可检测水平的Ia抗原（鼠类II类主要组织相容性抗原）。然而，当这些Ia阴性的P细胞转移至经伴刀豆球蛋白A刺激的脾细胞条件培养液中时，Ia抗原在24小时内出现。Ia抗原的增加是由于P细胞诱导合成了Ia抗原，而非从条件培养液中吸收了Ia抗原，也不是原群体中少量Ia阳性细胞选择性生长的结果。在抗原刺激的克隆T细胞系的上清液中也发现了Ia诱导活性，但在某些T细胞杂交瘤或T淋巴瘤EL-4的上清液中未发现。Ia诱导活性的存在与γ干扰素（IFN-γ）的存在相关。IFN-γ活性和Ia诱导活性的凝胶过滤图谱一致，且对应于表观分子量40,000 - 45,000。IFN-γ和Ia诱导活性在pH 2处理时均被破坏。这些结果表明IFN-γ或一种密切相关的分子诱导P细胞上的Ia抗原，并提示Ia抗原表达的调控可能是IFN-γ对免疫和造血系统作用的一个重要方面。
