INTERLEUKIN-7-ENHANCED CYTOTOXIC T-LYMPHOCYTE ACTIVITY AFTER VIRAL-INFECTION IN MARROW TRANSPLANTED MICE

Lethally irradiated BALB/c mice were reconstituted by syngeneic bone m arrow transplantation (BMT), and injected with recombinant interleukin 7 (rIL-7), recombinant interleukin 2 (rIL-2), or saline 10 days postt ransplantation. Intranasal infection with A/PR8/34 influenza virus 2 w eeks after BMT was associated with the highest survival rate in the rI L-7-treated group, The protective mechanism elicited by rIL-7, as mani fested by very low virus titers in the lung, involves T and B cell fun ctions, High hemagglutinin inhibition antibody levels were observed on days 7 and 12 post-challenge in the rIL-7 mice, Moreover, the anti-in fluenza cytotoxic T lymphocyte activity was induced primarily by rIL-7 , leaving the effect of rIL-2 on the same level as that of the control , Thus, rIL-7 promotes both T cell-mediated function and B cell produc tion during the immunodeficient state after BMT, This cytokine may pro ve a potential immunotherapeutic modality in BMT recipients.