The effects of vaccination with
RNA-free viral pseudoparticles, preinfection with non-pathogenic ecotropic virus, and induction of tolerance to
viral proteins in newborns on the outcome of murine immunodeficiency syndrome (
MAIDS) were studied. The parameters used to follow
disease progression were:
lymphopenia, circulating B and T8 cells, serum
IgG and
IgM levels, lymphoproliferation and skin graft rejection. Immunization with
RNA-free viral pseudoparticles had no effect on any of these parameters. Preinfection of adults with ecotropic virus and the induction of tolerance in newborns to virus
antigens both attenuated the early symptoms of
viral infection and delayed the onset of immunodeficiency and lymphoproliferation in some mice, but did not significantly alter the number of deaths due to
MAIDS. Failure of immune-based
therapy to produce successful protection against
MAIDS suggests that immune destruction caused by the persistent virus rather than hyperimmune activity is the main pathogenic factor in this disease.