The Reaction of Rheumatoid Factor with Various Animal IgG Globulin

Summary

Separated IgG from pooled human or animal sera were studied for their reactivity in the latex fixation test against whole serum from healthy individuals, from patients with rheumatoid factor when studied with the Waaler-Rose method as well as with the latex fixation test, against serum from patients with liver disease with similar rheumatoid factor and against serum from patients with other diseases and a positive latex fixation test. IgG proved equally reactive as gamma-globulin both before and after aggregation. IgG from pigs and horses showed less good reactivity, especially when aggregated. This phenomenon appeared in sera that reacted negatively in the Waaler-Rose test but positively in the latex fixation test. The type of the disease was irrelevant. The cross-reactivity between animal and human IgG as reactants to rheumatoid factor may support the opinion of the Fc fragment as the combining place for rheumatoid factor.