IMMUNITY AND RESISTANCE Inactivated Mouse Cytomegalovirus Vaccine: Preparation, Immunogenicity, and Protective Effect

Mouse cytomegalovirus (CMV) was rapidly and completely inactivated at 37 C by for-malin diluted 1:4,000. Of 18 mice that received two doses of inactivated mouse CMV, 16 survived challenge with 2 50070 lethal doses of mouse CMV; one of 11 mice receiving two doses of a control preparation survived the challenge (P < 0.005). After challenge with live virus, recognizable morbidity occurred in only four of 16 recipients of inactivated mouse CMV, but the virus was recovered from the salivary glands of 15 animals. Mice with reciprocal prechallenge titers of neutralizing antibody of <4 demonstrated signifi-cantly higher morbidity and mortality than mice with higher antibody titers. Adminis-tration of inactivated mouse CMV did not depress responsiveness of spleen cells to phytohemagglutinin. Most mice immunized with inactivated virus developed only mild or subclinical infections after challenge with lethal doses of mouse CMV. The spectrum of infection with cytomegalovirus (CMV) in normal individuals includes subclinical or nonspecific infection, hepatitis, an infectious mononucleosis-like syndrome, and polyneuriti