Immunogenic and antigenic epitopes of immunoglobulins. XXIII. Idiotypy and molecular specificity of human rheumatoid factors: analysis of cross-reactive idiotype of rheumatoid factor paraproteins from the Wa idiotype group in relation to their IgG subclass specificity.
The expression of idiotypic and variable region-associated isotypic determinants on a panel of human monoclonal rheumatoid factors (RF) was studied by means of murine hybridoma antibodies produced to two IgM-RF paraproteins. Fourteen RF paraproteins from patients with cryoglobulinaemia and one (RF-AN) from an Epstein-Barr virus (EBV)-established B-cell line from a patient with rheumatoid arthritis (RA) were studied. Nine RF paraproteins expressed a VkIIIb light chain sub-subgroup-associated cross-reactive idiotype and seven of these nine also expressed a heavy chain-associated cross-reactive idiotype. The reactivity of the monoclonal RF with human IgG subclass paraproteins revealed four patterns of molecular specificities: (1) RF reactive with an epitope common to all IgG subclasses; (2) RF reactive with an epitope expressed on IgG1, 2, 4 and G3m(s,t) which has histidine at 435, but not G3m(b) or G3m(g) which have arginine at 435; (3) RF reactive with an epitope expressed on IgG1, 2, and 4, but not IgG3 irrespective of allotypic markers; (4) RF reactive with epitopes expressed on some, but not all paraproteins within the subclasses. Four of five RF paraproteins that expressed both the heavy and light chain-associated idiotopes showed a similar pattern of reactivity with IgG subclass proteins.
Mageed
R A
RA
Department of Immunology, University of Birmingham Medical School, UK.
Carson
D A
DA
Jefferis
R
R
D003429:Cross Reactions; D000939:Epitopes; D006801:Humans; D007074:Immunoglobulin G / Q000145:classification; D007130:Immunoglobulin Idiotypes / Q000276:immunology*; D010266:Paraproteins / Q000276:immunology; D012217:Rheumatoid Factor / Q000276:immunology*
D000939:Epitopes; D007074:Immunoglobulin G; D007130:Immunoglobulin Idiotypes; D010266:Paraproteins; D012217:Rheumatoid Factor