Vaccinia virus semaphorin A39R is a 50-55 kDa secreted glycoprotein that affects the outcome of infection in a murine intradermal model

Abstract

Vaccinia virus (VV) protein A39R has amino acid similarity to the extracellular domain of a glycosylphosphatidylinositol-linked cell surface semaphorin (SEMA7A/CDw108) that has an immunological expression profile and binding properties, thereby implicating A39R as an immunomodulator. Previously, a closely related A39R protein expressed by ectromelia virus was shown to induce cytokine production and up-regulate ICAM-1 expression in mouse monocytes in vitro. In this study, we show that the A39R gene of VV strain Copenhagen (COP) encodes a 50-55 kDa secreted glycoprotein and is expressed late during infection. The A39R protein was secreted by eight of 15 strains of VV, but not by strain Western..