Immune Response to Japanese Encephalitis Virus in Mother Mice and their Congenitally Infected Offspring

The immune response to Japanese ncephalitis virus (JEV) was assessed in JEV-infected mice (mothers) and their offspring. The congenitally infected baby mice responded poorly in all assays for cell-mediated immunity. The total number of their splenic cells remained unaltered but the percentage of T cells was significantly reduced; a depressed elayed hypersensitivity response was seen against both homologous (JEV) and heterologous (sheep erythrocytes) antigens. In addition, significantly higher leukocyte migration inhibition (LM]) of spleen cells in the presence of specific antigen was observed. Adult mice infected during pregnancy demonstrated animpaired elayed hypersensitivity response to JEV antigen only. LMI was positive in mothers at 2 weeks post-partum, but not at later periods. During studies on the transplacental transmission of Japanese ncephalitis virus (JEV) in mice, we have shown persistence of the virus in thymus and brown fat for up to 17 weeks after infection and its reactivation during a consecutive pregnancy in spite of the presence of maternal antibodies (Mathur et al., 1982). Persistent infections can be produced by failure of the host's defence mechanism to eliminate invading viruses; on the other hand, viruses may develo