Selective B-cell expression of the MHV-68 latency-associated M2 protein regulates T-dependent antibody response and inhibits apoptosis upon viral infection

• Published in: Journal of general virology 2013-07, Vol.94 (Pt 7), p.1613-1623
• Main Authors: de Oliveira, V L, Almeida, S C P, Soares, H R, Parkhouse, R M E
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - immunology; Antibody Formation - immunology; Apoptosis - immunology; B-Lymphocytes - immunology; B-Lymphocytes - metabolism; B-Lymphocytes - virology; Gene Expression Regulation, Viral; Germinal Center; Hemocyanins - immunology; Herpesviridae Infections - immunology; Herpesviridae Infections - virology; Herpesvirus; Mice; Mice, Transgenic; Rhadinovirus - genetics; Rhadinovirus - metabolism; Rhadinovirus - pathogenicity; T-Lymphocytes - immunology; Tumor Virus Infections - immunology; Tumor Virus Infections - virology; Viral Proteins - genetics; Viral Proteins - immunology; Viral Proteins - metabolism; Virus Latency; Virus Replication
• ISSN: 0022-1317; 1465-2099; 1465-2099
• DOI: 10.1099/vir.0.050013-0

To better understand the role of the M2 protein of the murine herpes virus strain 68 (MHV-68) in vivo, B-lymphocyte-restricted, M2-transgenic mice were constructed. The transgenic mice contained normal B-cell subpopulations in bone marrow, lymph nodes and spleen. After immunization with sheep red blood cells, spleens from M2-transgenic mice had increased germinal centres. Transgenic mice responded to the T-cell-dependent antigen keyhole limpet haemocyanin (KLH) with higher levels of secondary IgM and IgG2a antibodies than WT mice. Normal and M2-transgenic mice were infected with WT and M2 frame-shift mutant (M2FS) MHV-68 viruses. The pathogenesis of M2-transgenic mice infected with the M2-deficient mutant virus did not revert to that observed upon infection of normal mice with WT virus. However, the higher reactivation levels late after M2-transgenic mice were infected with WT virus reflected the importance of M2 as a target for the immune response, and thus with an impact on the establishment of latency. Finally, there was markedly less apoptosis in B-cells from M2-transgenic mice infected with either WT or M2FS mutant than from similarly infected WT mice, consistent with the published inhibitory influence of M2 on apoptosis in vitro. Thus, M2 provides a strategy to increase the pool of germinal centre B-cells through inhibition of apoptosis in the infected cell.