Recombinant Herpesvirus Glycoprotein B (gB) Trimer

Background

Herpesviruses are a large family of enveloped double-stranded DNA viruses infecting a wide range of vertebrate hosts. The viral fusion protein glycoprotein B (gB) is conserved in all herpesviruses. It forms a trimeric complex on the viral envelope responsible for mediating the fusion of the viral envelope with the host cell membrane, allowing the virus to enter and infect the cell. This trimeric structure, formed by three identical gB proteins, undergoes large-scale conformational changes from a prefusion to a postfusion state after being triggered by receptor binding and other viral entry factors. This refolding process inserts hydrophobic fusion loops into the target cell membrane, ultimately merging the viral and cellular membranes to create a pore for viral entry.

Fig. 1 Conserved fusion protein glycoprotein B

Challenges in Producing Recombinant Herpesvirus gB Trimer Proteins

Recombinant herpesvirus gB trimers are notoriously difficult to produce because the protein is prone to misfolding and spontaneously shifting from its native prefusion conformation to a non-native postfusion state, reducing antigenicity.

gB also carries extensive N-linked glycans; incomplete or incorrect glycosylation often leads to ER retention or low yields.

In addition, the large, multi-domain ectodomain and trimeric interface make correct assembly challenging, and natural cleavage sites can cause premature processing if not engineered out. These factors together result in low or heterogeneous expression unless stabilizing mutations, optimized expression systems, and careful purification are applied.

Recombinant Herpesvirus gB Trimer at Creative Diagnostics

Creative Diagnostics has successfully developed several recombinant herpesvirus gB trimer proteins. Representative viruses include PRV (Pseudorabies virus), IBRV (Infectious bovine rhinotracheitis virus), and FHV (Feline herpesvirus).

All these proteins are expressed in CHO cells and are characterized as gB trimeric proteins. Our expression platform consistently delivers high titers of 5–6 g/L, enabling reliable supply for research, diagnostics, and vaccine development.

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