Effect of human adenovirus type 6 on the primary immune response in mice.

CFLP and BALB/c mice inoculated intraperitoneally with large doses of adenovirus type 6 (Ad6) showed a decreased humoral immune response to sheep red blood cells (SRBC) and circulating interferon was detected in their serum. The timing of infection was critical. Infection of mice 3--11 days before SRBC administration led to depression of the 19 S haemolytic plaque forming cell (HPFC) response in the spleen. When mice were given Ad6 and SRBC simultaneously on Ad6 14 days before or 1 day after SRBC, there was no decrease in the number of HPFC. The suppressive effect was dependent on the dose of virus and antigen. Heat and UV treatment completely abolished the immunosuppressive effect of the virus, suggesting that a great amount of infectious adenovirus is needed to induce immunosuppression in mice.