Low-Molecular-Weight Rheumatoid Factor*

A Monoclonal IgM Protein with Antibody-like Activity for Human Albumin

“…Certain rheumatoid sera also have intermediate comnplexes with a sedimentation coefficient between 9S and 17S. These dissociate in urea or acid to 7S units and are composed of anti-IgG and the reactant monomer IgG, both of which are 7S (31)(32)(33) (34) was able to show by analytical ultracentrifugation that the binding constant of aggregated, altered, and native 7S IgG for IgM rheumatoid factor subunits was approximately the same (i.e., 4 X 10O liter/mol). He suggested that the inability of native IgG to inhibit was due to an equilibrium that favored the rheumatoid factor-cell agglutinate due to the formation of multiple bonds between individual rheumatoid factor molecules and the multivalent aggregates of IgG.…”

Circulating and intra-articular immune complexes in patients with rheumatoid arthritis. Correlation of 125I-Clq binding activity with clinical and biological features of the disease.

“…Two major approaches were used in order to detect immune complexes in serum or in joint fluid. First, the existence of specific antigen-antibody systems was investigated and immunoglobulin-anti-immunoglobulin complexes were particularly demonstrated (4,5,(10)(11)(12)(13)(14)(15). Secondly, methods which are not specific for any particular antigen-antibody system were used.…”

IgM rheumatoid factor and low molecular weight IgM. An association with vasculitis

“…tDose, 5-15 mg daily for both groups workers (5). and IgG with antigamma globulin activity was subsequently demonstrated in such complexes (6,7). Thereafter IgG rheumatoid factor (IgG RF) was found in serum from rheumatoid patients of both the adult (8)(9)(10)(11)(12) and juvenile (13) varieties by a number of techniques, In rheumatoid synovial fluids aggregates of IgG capable of reacting with IgM RF have been demonstrated (14,15).…”