Direct activation of Sendai virus (HVJ)-specific cell-mediated immunity of mice for second set rejection of the virus-infected syngeneic tumor by noninfectious virus-sensitized spleen cells.

Syngeneic spleen cells (SPC) sensitized in vitro with noninfectious NVJ were shown to effectively stimulate mice to generate the HVJ-specific cell-mediated immunity for second set rejection (SSR) of virus-infected syngeneic leukemia cells. As few as 10(4) live but not disrupted SPC either infected with a temperature-sensitive mutant of HVJ (HVJts) or sensitized passively with ultraviolet (UV)-inactivated HVJts were active as immunogen. Syngeneic SPC as the carrier of virus could be replaced by allogeneic SPC or L cells, a fibroblast cell line, without reduction of the immunogenicity. Further study demonstrated that a special density of antigen on the surface of HVJts-sensitized SPC is required for high immunogenicity. It was suggested that live cells appropriately sensitized with noninfectious virus would serve as an excellent vaccine for virus-specific cell-mediated immunity.