Our monoclonal antibodies, clones CROMA 7, m55.01 and m55.02 recognize MCMV protein m55, also known as gB.
gB is a major envelope transmembrane glycoprotein, part of the protein machinery promoting the fusion process involved in virus entry. It is encoded by a gene transcribed in late phase of infection (after 16 h p.i.). gB is highly conserved among different herpesviruses and is a major target of virus-neutralizing antibody responses in CMV-infected animals and humans (Britt WY et al, J Virol, 1990). In addition, HCMV gB is also involved in cell adhesion and signaling capabilities (Boyle, KA et al, J Virol, 1998; Boyle, KA et al, Mol Cell Biol. 1999.) gB is present as several protein isoforms of different molecular masses, with the 130kDa form being precursor protein (Rapp, M et al, J Virol, 1992). It has been proposed for HCMV that a cellular protease cleaves precursor gB resulting in additional protein forms of lower molecular mass (Spaete RR et al, Virology 1988). This can be also observed in MCMV-infected cells stained with our M55.01 clone in western blot where clone M55.01 recognizes all gB forms whereas clone M55.02 recognizes only the highest molecular weight form (130kDa).
Our anti-M55/gB antibody clone Croma 7 has been validated in IHC and IF.