Interaction of Rheumatoid Factor with Infectious Vaccinia Virus-Antibody Complexes

Abstract

Rheumatoid factor (RF), isolated from sera of patients with rheumatoid arthritis, attached to infectious vaccinia virus-IgG (Vac-IgG) complexes. Neutralization did not occur until the Vac-IgG-RF complexes were incubated with either goat antihuman IgM or complement. The amount of RF that attached was proportional to the concentration of IgG incubated with the virus. The enhancement by RF of complement-mediated neutralization of Vac-IgG was not dependent upon the order of addition of the immunoreactants. Complement addition before, with, or after RF resulted in the same amount of neutralization. These observations suggest that under certain conditions RF may play a role in the defense against viral infections.