Interaction of Venezuelan Equine Encephalomyelitis Virus with Neutralizing Antibody: II. The Persistent Virus Fraction
FORT DETRICK FREDERICK MD
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The persistent virus fraction that results from the interaction of Venezuelan equine encephalomyelitis VEE virus with antiviral serum is an infectious virus-antibody complex sensitized virus that can be neutralized by anti-IgG serum. The quantities of virus sensitized by VEE antiserum and neutralized by anti-IgG serum depend on the concentration of these sera. In contrast to the marked temperature and time dependence of VEE virus neutralization by antiviral serum, neutralization of sensitized virus by anti- IgG serum is more rapid almost complete within 1 min at .35C and less sensitive to temperature. Evidence that virus sensitization preceded neutralization indicates that the persistent virus fraction is formed before virus neutralization has actively begun. Within certain limits, neutralization of sensitized virus by anti-IgG serum is species-specific. Differences in the ability of anti-IgG, anti-IgA, and anti-IgM sera to neutralize sensitized virus indicate that the reaction is also influenced by the specificity of the anti- immunoglobulin. Sensitized virus was partially neutralized by goat antiserum to monovalent Fab fragments on human IgG and, to a lesser degree, by the Vc fragment. Sensitized virus was neutralized by an in vitro mixture of these fragments to almost the same degree as that neutralized by goat antiserum to intact human IgG. Indirectly, these findings suggest a role for the Fc fragment in virus neutralization.
- Anatomy and Physiology