Immunopathology of Mouse Hepatitis Virus Type 3 Infection

Abstract

Abstract Humoral and cell-mediated immune responses were studied in resistant and susceptible strains of mice infected with mouse hepatitis virus type III (MHV3). Virus was maintained by regular passages in susceptible DBA/2 mice and assayed in DBA/2 mice by LD50 determination. Normal resistant A strain mice were able to clear the virus from liver, brain, and serum within 7 days after infection. No neutralizing antibody was found. Transfer of serum from immunized A strain mice was not effective in protecting susceptible DBA/2 mice against challenge with virus. In A strain animals resistance to MHV3 developed rapidly during the 3rd week of life. During the period of susceptibility, newborns were protected neither by transplacental passages of anti-MHV3 antibodies nor by injection of “educated” thymus cells. These results suggest that the development of resistance to MHV3 infection in mice cannot be explained solely on the basis of humoral or cell-mediated immunity.