Protection and therapy of experimental herpesvirus infections in mice with immunomodulating Propionibacterium avidum...

Protection and therapy of NMRI mice with experimental herpes virus (HSV-1) encephalitis were investigated using heat-killed, lyophilized Propionibacterium avidum KP-40 (PA) and/or the herpes-specific antiviral substance acyclovir (ACL) as immunomodifier. Poly I:C as a potent macrophage activator was used as a reference compound for PA. Survival of experimental HSV-1 infections during 18 days following the inoculation of viruses was used for the evaluation of the effects of immunotherapy. The applied model of HSV-1 infection resulted in a mortality of about 87% of NMRI mice at 7-16 days following the inoculation of the virus. Treatment with ACL or Poly I:C at the day of HSV-1 infection resulted in a lowering of the mortality rate to about 40% (p < 0.05). PA applied 4 days before HSV-1 infection lowered the mortality rate to 27%, while treatment 2 days after infection was less effective and the mortality rate reached 44%, although still being significantly lower (p < 0.01) than in untreated controls. A combined treatment with ACL and PA on the day of HSV-1 infection protected 93% of animals against the development of clinically detectable herpesvirus encephalitis.