Analysis of human antiviral cytotoxic T-lymphocyte responses for vaccine trials using cryopreserved mononuclear leukocytes: demonstration of feasibility with influenza virus-specific responses.

The feasibility of measuring virus-specific human cytotoxic T-lymphocyte (CTL) activity by using cryopreserved mononuclear leukocytes to support clinical vaccine trials was addressed. Autologous fresh and cryopreserved cells from the same sample of peripheral blood were used as sources of CTL precursors and were tested for influenza virus-specific activity. The data indicated that virus-specific CTL activity could be measured by using cryopreserved cells; this could also be done in assays that are designed to characterize the responsible effector cell population.