Hallmarks of the
acquired immune deficiency syndrome (
AIDS) are immunologic alterations, frequently associated with
opportunistic infections. To study such associations, LP-BM5 murine
retrovirus infection was used as a murine model of
AIDS. Retrovirally infected and uninfected mice were fed a 5% (v/v)
ethanol diet for 55 days and then fed
a 7% v/v
ethanol diet for the final 7 days to assert the role of
ethanol as a cofactor in development of
murine AIDS. There was a reduction in polymorphonuclear neutrophils count in
ethanol-fed groups. Neutrophils increased in retrovirus-infected groups, except those vaccinated 10 days before challenge with live bacteria. The percentage of splenic lymphocytes in the retrovirus-infected group was reduced in comparison with controls. Survival of the mice challenged intraperitoneally with Streptococcus pneumoniae was increased by vaccination and suppressed by dietary alcohol.
Retrovirus infection caused a much faster death rate after bacterial challenge than nonretrovirus infected controls. Vaccination played an important role in delaying the death rate in all treated groups. Transferring spleen cells from healthy, unimmunized mice also enabled the retrovirally infected mice to survive the
bacterial infection longer. Enhancement of resistance to S. pneumoniae by vaccination and transfer of immunocompetent cells to mice immunosuppressed by retroviral
infection show the potential to use
immunomodulation to affect
disease resistance in
AIDS.