Human peripheral blood lymphocytes have been sensitized in vitro to influenza virus antigen. After an induction period of 4--14 days, cytotoxic cells which lyse autologous influenza virus-infected lymphoid cells could be demonstrated VSports手机版. The cytotoxic cell is a T lymphocyte which shows specificity for sensitizing influenza virus type A or B. It cannot distinguish between major subtypes of influenza A virus. The use of virus-infected normal lymphoid cells as target cells overcame the difficulties of nonspecific killing encountered with some transformed cells. .