The course of LCMV infection in gnotobiotic and conventional adult mice pretreated with attenuated NDV vaccine.

A single intraperitoneal treatment with two different doses of live Newcastle Disease Virus (NDV) containing attenuated NDV vaccine one day before intracerebral inoculation with lymphocytic choriomeningitis virus (LCMV) had no influence on the ratio and time of deaths after infection with a 100 LD50 dose of LCMV either in gnotobiotic or in conventional mice. There was no difference either in the LD50 values determined on the basis of three parallel LCMV titration performed on mice pretreated with two different doses of vaccine or untreated. NDV vaccine pretreatment thus did not influence the cellular immune response to LCMV infection either in gnotobiotic or in conventional adult mice. As the NDV vaccine increased the cellular immune response to LCMV infection in suckling mice according to earlier results, the present results reinforce our earlier statement that the direction of immunomodulatory effects can be influenced by age.