[Effect of microbial immunomodulators on the course of lymphocytic choriomeningitis virus infection in old mice with physiological thymus involution].

Aged mice with physiological thymus involution were treated intraperitoneally with 0.2 ml of live Newcastle Disease Virus (NDV) containing attenuated NDV vaccine (HA titre: log 2(16)/ml) one day before or with Mannozym (0.1% zymosan suspension) four days and one day before intracerebral inoculation with 100 LD50 dose of LCMV. One dose of M was equal to 40 mg/kg zymosan. Both, NDV vaccine and M pretreatments contributed to the development of fatal lymphocytic choriomeningitis, thus enhanced the cellular immune response to LCMV infection. Present results are compared with earlier results which were attained on young adult suckling mice in similar system with pretreatment with different microbial immunomodulators. Present results reinforced the authors' earlier observations that the direction and degree of immunomodulatory effects can be influenced by the actual conditions, like age, of the immune system.