Characterization of human herpesvirus-6(U1102) and (GS) gp112 and identification of the Z29-specified homolog

Abstract Monoclonal antibody 2D10 (MAb 2D10) raised toward human herpesvirus-6(U1102) [HHV6(U1102)] immunoprecipitated three glycosylated peptides, M r 112,000, 64,000, and 58,000, designated as gp112 from U1102-infected lymphocytes. Pulse-chase experiments suggest that the M r 64,000 and 58,000 polypeptides are very likely generated by post-translational cleavage of the M r 112,000 polypeptide. MAb 2D10 neutralized virion infectivity in the presence of complement, suggesting that gpl12 is located in the virion envelope. MAb 2D10 did not prevent the appearance of HHV6-specific cytopathic effect. MAb 2D10 was reactive with denatured gpl12 in immunoblots. HHV6 isolates form two clusters (Schimer, Wyatt, Yamanishi, Rodriguez, and Frankel, Proc. Nat. Acad. Sci. USA 88, 5922; Ablashi, Balachandran, Josephs, Hung, Krtueger, Kramarsky, Salahuddin, and Gallo, Virology 184, 545). MAb 2D10 reacted by immunofluorescence and immunoprecipitation with the prototypes of each cluster, GS and Z29. Whereas the proteins immunoprecipitated by MAb 2D10 from GS-infected lymphocytes had an electrophoretic pattern very similar to that of U1102 gpl12, the homologous glycoprotein immunoprecipitated from Z29-infected lymphocytes consisted of three polypeptides with M r 102,000, 59,000, and 50,000. The data suggest a variation among HHV6 isolates as far as this glycoprotein is concerned.