Effects of serum versus plasma on agglutination of antibody-coated indicator cells by human rheumatoid factors.
Plasma and serum contain an inhibitor (I) of the agglutination of rabbit IgG-coated sheep erythrocytes by human rheumatoid factor (RF). Plasma but not serum contains an inhibitor of the inhibitor (I/I) which allows RF to interact with its target. In normal blood, there is more I than I/I, and I can be removed by solid-phase chromatography through concanavalin A (Con A). Plasma I/I is heat labile being eliminated by heating at 56 degrees C for 30 min. Addition of exogenous calcium clots EDTA plasma, causing an irreversible loss of I/I, and suggesting its involvement in the clotting cascade. The absence of I/I from Factor V-deficient plasma and destruction of I/I by Russell's viper venom indicate I/I either is associated with or is a part of Factor V. These findings suggest a balanced interplay between I and I/I, and indicate results of immunological tests done in vitro may not accurately reflect immune function in vivo. This seems to represent an unexplored link between hemostasis and immunity.
Faulk
W P
WP
Methodist Center for Reproduction and Transplantation Immunology, Methodist Hospital of Indiana, Inc., Indianapolis 46202.
Torry
D S
DS
McIntyre
J A
JA
D000372:Agglutination Tests; D000925:Anticoagulants / Q000494:pharmacology; D000937:Antigen-Antibody Reactions / Q000187:drug effects; D005165:Factor V / Q000502:physiology*; D006001:Glycoconjugates / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D037102:Lectins; D010949:Plasma / Q000276:immunology*; D012217:Rheumatoid Factor / Q000276:immunology*
D000925:Anticoagulants; D006001:Glycoconjugates; D037102:Lectins; D005165:Factor V; D012217:Rheumatoid Factor