B cell stimulatory factor-2 is involved in the differentiation of cytotoxic T lymphocytes.

TLDR

CTL induction from precursor T cells requires antigen and lymphokine signals, and prior work has shown that IL‑2, IFN‑γ, and a cytotoxic differentiation factor (CDF) are necessary for murine thymocyte differentiation. Cloning CDF from the human T cell line C10‑MJ2 revealed that its gene is identical to B cell stimulatory factor‑2 (BSF‑2), IFN‑β2, and a 26‑kDa protein. BSF‑2 drives differentiation of Ly‑2⁺ CTL in the presence of IL‑2, with IFN‑γ further enhancing cytotoxicity, and induces serine esterase expression that correlates with cytotoxic activity, confirming BSF‑2 as a CTL differentiation factor that promotes lytic protein production.

Abstract

Abstract The induction of cytotoxic T lymphocytes (CTL) from precursor T cells requires both antigen and lymphokine signals. Previous work from our laboratory has indicated that three lymphokines are required for the induction of CTL from murine thymocytes; interleukin 2, interferon-gamma (IFN-gamma), and a partially characterized factor referred to as cytotoxic differentiation factor (CDF). While attempting to clone CDF from the human T cell line C10-MJ2, we found that a gene encoding CDF-like activity is identical to the gene encoding the factor known variously as B cell stimulatory factor-2 (BSF-2), IFN-beta 2, and 26-kDa protein. We report here that BSF-2 can induce the differentiation of Ly-2+ CTL from murine thymocytes in the presence of interleukin 2 and that the level of cytotoxicity is augmented by the addition of murine IFN-gamma. Serine esterase, a marker for cytotoxic granules in CTL, was induced only in the presence of BSF-2, and the level of serine esterase activity correlated with the level of serine esterase activity correlated with the level of cytotoxicity. These data suggest that BSF-2 is a differentiation factor for CTL and that it functions in part by inducing proteins required for mediating target cell lysis.