THE ASSOCIATION OF RHEUMATOID FACTOR WITHANTINUCLEAR FACTOR ACTIVITY

Do polyclonal rheumatoid factors carry an 'internal image' of cytomegalovirus, Epstein-Barr virus and nuclear antigens?

Rabbit antisera have been prepared against isolated rheumatoid factors (RF's). It was considered that RFs are anti-idiotype antibodies and that the anti-RF antisera had anti-anti-idiotype specificity. Furthermore, it was considered that the RF's carry an "internal image" of the putative "antigen X" and that the rabbit antisera would have specificity for this "antigen-X". Reactions of the rabbit antisera with the early and late antigens of CMV, EBV antigens and nuclear antigens suggest that there may be an "internal image" of these antigens in rheumatoid factor molecules and that they all may be related to the immunogenesis of RF.

False RIA IgM titres to herpes simplex virus and cytomegalovirus: factors causing them, and their absorption by protein A-Sepharose/IgG-protein A-Sepharose

A method for the absorption of false radioimmunoassay (RIA) IgM titres against herpes simplex virus (HSV) and cytomegalovirus (CMV) is presented. The serum specimens were absorbed by a mixture of protein A-Sepharose and protein A-Sepharose saturated with normal human gamma globulin (PAS/IgG). The detection of rheumatoid factor of IgM class (IgM-RF) as well as antinuclear antibodies (ANA) of both IgM and IgG class by solid-phase RIA is also described, and their role in the false IgM results was studied. It was found that the PAS/IgG absorption removed 50-90% of both IgM-RF and total IgG. The reduction of IgM-ANA clustered at 50-90% or nothing, whereas the reduction of IgG-ANA was approximately 50%. The studies with HSV and CMV antigens indicated that the removal of false IgM titres was more effective than the removal of each of these four factors. It was concluded that the IgM-RF titres alone were not sufficiently high to explain the false IgM results, but the ANA activity probably contributed.

Immunofluorescence studies on the subcomponents of the first component of complement (C1): detection of C1q and C1s in different cells of biopsy material and on human as well as on guinea pig peritoneal macrophages

The first component of complement (C1) is a macromolecule consisting of three distinct subcomponents, C1q, C1r, and C1s. In regard to its production site and its role in phagocytic processes it was of interest to find out whether these different subcomponents could be detected in human biopsy material only as a complex in individual cells or whether C1 subcomponents could be found on different cells. To study this question, monospecific fluorescein-labelled anti-human-C1q IgG and monospecific rhodamine-labelled anti-human C1q IgG were used. Biopsy material from human rectum was stained with fluoresceinated antisera, either by use of one antiserum or by double staining. Using this technique, these observations were made: C1q as well as C1s were detectable in individual cells in the subepithelial area of the gut. Furthermore, C1q and C1s could be found together in the same cell or separately in different cells. These findings were supported by experiments with cultured peritoneal macrophages either from human or from guinea pig. The examination of the cultured cells with the two antisera revealed that individual cells were stained either by anti-C1q or by anti-C1s antibodies. The specificity of the detection of the individual subcomponents was also proven by the peroxidase technique and by using fluoresceinated anti-human C1q F(ab')2. The membrane immunofluorescent staining revealed the presence of C1q on the membrane of the macrophage.

IgM-rheumatoid factors cross-reactive with IgG and a cell nuclear antigen: immunopathological implications?

The cross-reaction of IgM-rheumatoid factors (IgM-RF) with a cell nuclear antigen has been further investigated by immunofluorescence procedures. This reaction appears to be optimal at pH 8-9, and fails to occur at pH 6.5. No evidence was obtained by immunofluorescence that IgM-RF bound to the cell nuclear antigen fixes complement. It would appear that the nuclear reactivity of IgM-RF may be of limited immunopathological significance, though this reaction is of note in understanding the behavioural nature of rheumatoid factors.

IgM-rheumatoid factors cross-reactive with IgG and a cell nuclear antigen: apparent 'masking' in original serum

Fourteen out of fifteen IgM-rheumatoid factor (IgM-RF) preparations isolated from high-titred seropositive rheumatoid sera by affinity chromatography on immobilized human IgG have been shown to cross-react with a cell nuclear antigen, as manifest by positive immunofluorescent anti-nuclear antibody (ANA) staining on rat liver and kidney tissue sections. The cross-reacting ANA activity within isolated IgM-RF preparations was inhibitable by both human and rabbit IgG, as well as by isolated rat liver chromatin, and could be isolated from seropositive ANA-negative sera. It would appear that this cross-reacting ANA activity can be masked in the original seropositive serum and may often require purification of RF from serum for its manifestation.

Antinuclear factors in rheumatoid arthritis. Increasing organ-non-specificity with increasing reactivity of rheumatoid factor with heterologous gamma globulin

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Cellular reaction to complexes formed between rheumatoid factor and aggregated human gamma globulin

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