Vaccinia virus extracellular virus-specific B5 protein (B5)

The Vaccinia virus extracellular virus-specific B5 protein, encoded by the B5R gene, is a critical type I transmembrane glycoprotein essential for the formation and function of the extracellular enveloped virus (EEV) form of the virus (UniProt: P16584). It plays a pivotal role in the viral life cycle by facilitating the wrapping of intracellular mature virus (IMV) particles with host-derived membranes, a process necessary for efficient cell-to-cell spread and systemic dissemination (PubMed: 15140980). Structurally, B5 contains four short consensus repeat (SCR) domains that mimic host complement control proteins, thereby aiding in immune evasion by protecting the virus from complement-mediated neutralization (NCBI: PMC114026). As a primary target for neutralizing antibodies, B5 is a key antigenic component in vaccines and therapeutic products like Vaccinia Immune Globulin Intravenous (VIGIV), which is used to treat severe adverse reactions to the smallpox vaccine and other orthopoxvirus infections (FDA: VIGIV Label). In addition to B5, other viral proteins such as p37 (encoded by F13L) serve as therapeutic targets; for instance, the antiviral drug Tecovirimat specifically inhibits p37 to prevent the formation of EEV (PubMed: 18321971). Together, these proteins represent a suite of targets for managing orthopoxvirus-related diseases, including smallpox and Mpox, by disrupting viral egress and neutralizing infectious particles.

Other names

B5Rp42Extracellular enveloped virus membrane glycoprotein B5Vaccinia virus B5R proteinEEV-specific glycoprotein B5Vaccinia virus extracellular virus-specific B5 protein and other vaccinia viral antigens/immune evasion proteins

Neutralization of extracellular enveloped virus (EEV) particles and inhibition of viral wrapping and egress to prevent cell-to-cell spread.