Interleukin-7-enhanced cytotoxic T lymphocyte activity after viral infection in marrow transplanted mice

Lethally irradiated BALB/c mice were reconstituted by syngeneic bone marrow transplantation (BMT), and injected with recombinant interleukin 7 (rIL-7), recombinant interleukin 2 (rIL-2), or saline 10 days posttransplantation. Intranasal infection with A/PR8/34 influenza virus 2 weeks after BMT was associated with the highest survival rate in the rIL-7-treated group, The protective mechanism elicited by rIL-7, as manifested by very low virus titers in the lung, involves T and B cell functions, High hemagglutinin inhibition antibody levels were observed on days 7 and 12 post-challenge in the rIL-7 mice, Moreover, the anti-influenza 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 production during the immunodeficient state after BMT, This cytokine may prove a potential immunotherapeutic modality in BMT recipients.