Heavily Isotype-Dependent Protective Activities of Human Antibodies against Vaccinia Virus Extracellular Virion Antigen B5

Ectromelia Virus Inhibitor of Complement Enzymes Protects Intracellular Mature Virus and Infected Cells from Mouse Complement

“…The ability of serum when combined with anti-ECTV antibody to neutralize about half of the EEV demonstrates the activity of the serum. Consistent with published findings (5,6,62), the addition of antiviral antibody can overcome the EEV's normal resistance to complement. Taken together, these results highlight the importance of employing a homologous system, preferably from the natural host, in analyzing the importance of complement inhibitors to virulence.…”

The Vaccinia Virus Complement Control Protein Modulates Adaptive Immune Responses during Infection

“…Recent efforts to better define the antiviral functions of Abs during poxvirus infection have revealed an important role for complement in Ab-mediated protection (2, 3). Benhnia et al showed that monoclonal Abs (MAbs) specific for the EV protein B5 that are able to initiate complement-mediated lysis of infected cells and complement-dependent neutralization of EV particles in vitro provide better protection against VACV challenge following passive immunization (2,3). Furthermore, the enhanced protection provided by these MAbs in vivo was reduced when mice that had been passively immunized were depleted of complement prior to challenge, demonstrating that enhanced protection depended on the ability of MAbs to activate complement (3).…”

Unusual Features of Vaccinia Virus Extracellular Virion Form Neutralization Resistance Revealed in Human Antibody Responses to the Smallpox Vaccine

“…B cell responses against both EV and MV forms of VACV can be important components of protective immunity in animal models and likely contribute to the protection of immunized humans against orthopoxviruses (20,42,47). Neutralizing Abs against EV have been of particular interest, given the essential role of EV for viral pathogenesis (47)(48)(49)(50)(51). Animals receiving the smallpox vaccine raise Abs against B5 and/or A33 surface antigens (10,49,52,53).…”