VACV B5 Env Specific Neutra™ Antibody Products

Vaccinia virus (VACV) is an enveloped virus of the poxvirus family, commonly used as a vaccine vector. It has two forms of infection: the intracellular mature virus (IMV), which initiates infection, and the extracellular virus (EV), which facilitates spread. The B5 envelope glycoprotein is a type I membrane glycoprotein found on the EV membrane. B5 is involved in the merging of the viral envelope with the host cell membrane and is essential for virion formation and viral pathogenesis. Structurally, B5 has an extracellular domain involved in receptor binding and fusion, a single transmembrane domain, and a small cytoplasmic tail. It interacts with other viral proteins to facilitate viral maturation, stability, and infectivity.

Role of B5 Protein in VACV

B5 protein plays a crucial role in VACV viral entry and infectivity. It facilitates fusion between the viral envelope and host cell membrane, enabling virus entry into host cells. B5 also participates in viral protein transport, directing its localization to intracellular sites for packaging into new virions. B5 helps the virus's proteins glycosylate correctly, assisting in its functional stability and viral maturation. B5 forms a complex with the A34 protein, which is critical for the formation of the EV, aiding in viral spread by enabling virus particle stability and cell-to-cell transmission. Partial deletion of B5 protein disrupts these processes, leading to reduced viral spread and infectivity.

Immune Response of B5 Protein

B5 protein contains four short common repeat (SCR) domains which are recognized by the host immune system. These domains are key targets for immune surveillance, and their presence can stimulate an immune response. Deleting the SCR domains from B5 protein helps the virus evade detection by the host immune system, enhancing its ability to persist and spread. B5 protein also participates in modulating the host's immune response. It helps the virus evade detection by the host immune system by inhibiting host cell signaling pathways, such as those involving interferons, which are crucial for antiviral defense. B5 protein also prevents the activation of certain immune cells, such as dendritic cells, by altering cell surface interactions and minimizing immune activation. This immune evasion helps VACV establish and maintain infection, allowing it to spread more efficiently in the host.

Fig. 1 Summary of VACV-induced host protein synthesis shutoff.^{1, 3}

Anti-VACV B5 Protein Neutralizing Antibodies

The B5 protein is a crucial target for neutralizing antibodies. Neutralizing antibodies targeting B5 proteins are crucial for neutralizing viral infectivity, which can block EV release and prevent the virus from disseminating within the host. Research focuses on developing monoclonal antibodies (mAb) against B5 for potential therapeutic and diagnostic applications, particularly in combating VACV infections. These antibodies can also be used to study the mechanisms of viral egress and neutralization. Antisera targeting B5 can neutralize EV in a plaque reduction assay and prevent "comet formation," the in vitro indicator of EV's spread between cells. Research has also demonstrated that chimpanzee and human mAbs against the B5 protein effectively neutralize both VACV and smallpox viruses and protect mice from VACV infection by interfering with viral propagation.

Fig. 2 Evaluation of binding IgG responses to VACV B5 and MPXV B6 by neutralizing antibodies.^2,3

Creative Biolabs offers high-quality anti-B5 envelope neutralizing antibody products to assist your research projects.

REFERENCES

1. Dhungel, Pragyesh, et al. "Vaccinia virus as a master of host shutoff induction: targeting processes of the central dogma and beyond." Pathogens 9.5 (2020): 400.
2. Zhao, Runchu, et al. "Two noncompeting human neutralizing antibodies targeting MPXV B6 show protective effects against orthopoxvirus infections." Nature Communications 15.1 (2024): 4660.
3. Distributed under Open Access license CC BY 4.0, without modification.