Kinetic study of rheumatoid factor influence on complement-mediated modulation of immune precipitation

Human monoclonal IgM kappa rheumatoid factor PA (mRF) expressed various effects on complement-dependent modulation of ovalbumin/antiovalbumin lattice formation measured kinetically by laser light scattering (LLS): (1) in the absence of complement, mRF (44.2-177 U/ml) caused enhancement of LLS in a dose-dependent manner; (2) mRF partially prevented expression of complement-mediated inhibition of lattice formation and, at the same time, complement inhibits mRF-dependent LLS enhancement; (3) complement caused disruption of lattice-mRF bonds during solubilization of preformed lattice-mRF complex as demonstrated by specific mRF activity in supernatants. This effect is dependent on complement activity and on both complement and mRF concentrations; (4) ovalbumin/antiovalbumin complexes gradually lost the ability to react with mRF during the first 2 min of complement-mediated inhibition of lattice formation.