Rheumatoid arthritis and its association with HLA-DR antigens. II. Antibodies to native connective tissue antigens detected by enzyme linked immunosorbent assay.

The distribution of frequencies of HLA-DR alloantigens in HLA-DR4 negative subjects was determined in patients with Rheumatoid arthritis (RA) and normal individuals. An increased incidence of HLA-DR1 alloantigen in DR4 negative RA patients (45.9%) compared with DR4 negative healthy controls (23.6%) was found. The difference became significant when the incidence of DR1 was compared between patients with severe disease stages (III-IV) (75%) in contrast to 32% of incidence in patients of the milder stages (I-II) (p less than 0.05). Using Enzyme Linked Immunosorbent Assay we have determined the incidence of serum antibodies to native bovine type I and type II collagens and proteoglycans in patients with RA. Presence of serum antibodies to native type I collagen was detected in 59% of patients with RA, 60% of sera exhibited reactivity to type II collagen and 12% had antibodies to proteoglycans. There was no correlation between the presence of antibodies to type I and II collagens and disease stages, however, the incidence of serum antibodies to proteoglycans was increased in severe disease stages. On the other hand, the presence of high levels of antibodies to type I collagen was associated to HLA-DR1 antigen, (p less than 0.05).

Comparison of tanned cell hemagglutination and counter immunoelectrophoresis test in the detection of antibodies to extractable nuclear antigens (ENA) and to DNA in the systemic lupus erythematosus.

A comparative study of tanned cell hemagglutination (TCH) and counterimmunoelectrophoresis (CIE), two easy and reliable methodes for the routine detection of antibodies against nuclear antigens was performed. Antibodies against ENA, RNA-ase sensitive ENA and DNA antigens were searched in patients affected by systemic lupus erythematosus (SLE). Analysis of the results obtained for a particular antibody using TCH and CIE techniques suggests that both methods should be used for the detection of antibodies to nuclear antigens since in several cases antibodies were detected by one method and not for the other. Besides, the frequency of antibodies to ENA, RNA-ase sensitive ENA and DNA revealed by both techniques is similar to the results reported by others employing laborious tests. TCH and CIE serve as a screen to determine the presence of an antibody system and seems to provide the sensitivity enough as to be used in the smaller routine laboratories that wish to provide services for antibodies to nuclear antigens. When tanned cell hemagglutination was used looking for antibodies to DNA or ENA in the sera of patients affected by SLE it proved to be useful since in samples where antibodies to DNA were absent or at very low titres, antibodies to ENA were present in titres ranging from 1:9 to 1:6 561. The authors think this is of considerable importance since the variety of clinical features seen in different subjects with SLE is often accompanied by different specificities or types and amounts of autoantibodies and that certain combinations of these antibodies coincide with specific clinicopathological abnormalities.

Rheumatoid arthritis and its association with HLA-DR antigens. I. Cell mediated immune response against connective tissue antigens.

HLA-DR antigens and cellular sensitivity to native bovine type I and type II collagen and proteoglycans were examined in patients with classic rheumatoid arthritis (RA) and normal individuals. Fifty eight percent of patients with RA (n = 88) and 28% of normals (n = 52) were DR4+ (pc less than 0.01). DR4 phenotype was significantly increased in patients with severe disease stages (III-IV), as defined by the ARA criteria, in contrast to those showing mild disease stages (I-II) (p less than 0.05). Furthermore, peripheral blood mononuclear cells from 55 patients and 30 controls were evaluated for the in vitro production of leukocyte inhibitory factor in response to native type I and type II collagen and proteoglycans. By using this assay, cells from the arthritic group exhibited a statistically significant response when stimulated with native type I collagen and proteoglycans. The cellular immune response was not associated with any particular HLA-DR antigens, or to the disease stage or severity.

Humoral autoimmune response to rat male accessory glands. Comparative specificity studies of auto and heteroantibodies.

A comparison of specific antibodies induced by a saline extract of chemically modified rat male accessory glands (MRAG) in isologous (male and female rats) and heterologous animals (rabbits and a goat) was made. This study was focused on the specificity of the antibodies confronted with saline extract of rat male accessory glands (RAG), their Sephadex G-100 fractions and autoantigen fragments. Specificity studies with Sephadex G-100 fractions of RAG showed that whereas in male rats only the antibodies reactive with Fraction 1 containing autoantigens were detected, one additional population of antibody with different specificity was revealed in female sera. In contrast, antibodies against several other macromolecules were present in heterologous sera. When analyzed for the serum specificity against three enzymatic fragments of autoantigen, the main specificities of male and female sera were different.

Characterization of an antigen from rat male accessory glands.

An isolated soluble antigen involved in the autoimmune response against rat male accessory glands migrated as a double band when it was submitted to analytical disc polyacrylamide gel electrophoresis and as a homogeneous molecular species in SDS electrophoresis. The purified antigen had a molecular weight of approximately 78 K by SDS electrophoresis and 80 K by gel filtration chromatography. The antigen was identified as a protein and displays androgen dependency. The purified fraction was pathogenically active in microgram doses and induced humoral and delayed-type hypersensitivity responses. Besides, lesions were observed in the target organ. The cellular infiltration was located in prostate glands according to the localization of antigen by immunofluorescence findings.

Regulation of experimental allergic encephalomyelitis. Part 5. Role of the recipient in suppressor cell induction.

Suppressor cells that regulate experimental allergic encephalomyelitis (EAE) are present in spleens of Lewis rats that have recovered from the disease, as demonstrated by adoptive transfer of suppression to normal recipients. However, lethally irradiated recipients (850 rad) of spleen cells from recovered donors are not protected against EAE. Indeed, onset of EAE is accelerated in these irradiated recipients. These findings suggest that the host participates in the suppression of EAE.

Isolation of rat male accessory glands autoantigens by affinity chromatography.

The autoantigens of rat male accessory glands were isolated by a short procedure which involved 1) immunization of rats with chemically modified rat male accessory glands' saline extract; 2) purification of immunoglobulin G (IgG) from the autoantisera by chromatography on DEAE-Sephadex A-50;3) coupling of rat IgG anti-rat male accessory glands with 4-B activated Sepharose; 4) addition of rat male accessory glands' saline extract and removal of autoantigens by glycine-HCl, pH 2.9. The purity of the eluted autoantigens was determined by polyacrylamide disc gel electrophoresis (PAGE). These components retained their immunologic activity as demonstrated by inhibition of tanned cell hemagglutination and double immunodiffusion gel precipitation.