Persistent infection of mice with the virus of lymphocytic choriomeningitis: virus-specific immunological tolerance.

Lymphocytic choriomeningitis (LCM) virus-infected culture cells as targets were markedly reduced in numbers when incubated in vitro with spleen cells from LCM virus-immune mice, even if the cells were taken months after a subcutaneous immunizing infection of the donor animal. Spleen cells from mice persistently infected with LCM virus had no effect on target cells. Also, mitomycin C-blocked LCM virus-infected culture cells stimulated the incorporation of radiolabeled thymidine into spleen cells from LCM virus-immune mice. No stimulation was observed with spleen cells from LCM virus carrier mice. It was concluded that cell-mediated immunity directed against LCM virion surface antigen(s) is absent in LCM virus carrier mice.