Evidence for a subset of rheumatoid factors that cross-react with DNA-histone and have a distinct cross-idiotype.

Cross-reactivity of a monoclonal rheumatoid factor with an antigen present on IgG and DNA-nucleoprotein was demonstrated, and evidence presented that the combining site of the antibody was involved in the reaction. The antigen on the DNA-nucleoprotein was shown to involve both DNA and histone fraction H2A + H2B and was trypsin sensitive. The relative binding affinity of the antibody appeared to be greater for IgG than the DNA-histone antigen. Similar polyclonal cross-reactive rheumatoid factors were found in a variety of diseases. A high incidence was found among patients with rheumatoid arthritis and mixed connective tissue disease. None were detected in patients with systemic lupus erythematosus and idiopathic cryoglobulinemia. Studies on one representative isolated polyclonal rheumatoid factor demonstrated the same reactivity with DNA-histone H2A + H2B as the monoclonal antibody. Cross-idiotype studies using antigen-binding inhibition methods demonstrated the same cross-idiotype on the polyclonal and the monoclonal rheumatoid factor which reacted with DNA-histone. This cross-idiotype was shown to be distinct from the cross-idiotypes previously demonstrated on monoclonal IgM proteins with anti-gamma-globulin activity.

A serum protein associated with chromatin of cultured fibroblasts.

Antibodies to chromatin proteins from human and mouse fibroblasts which have been cultured for more than 25 generations with heterologous serum show specificity for a homologous alpha-serum protein. These results indicate that among the chromatin-associated proteins there is one (or more) which has extensive structural similarity to a serum protein. This is the first direct evidence that a serumlike protein or proteins could be chromatin associated in vivo, as has been suggested by experiments showing in vitro interaction between DNA and certain serum proteins.

Immunogenic DNA-related factors. Nucleosomes spontaneously released from normal murine lymphoid cells stimulate proliferation and immunoglobulin synthesis of normal mouse lymphocytes.

The cell-free supernatants of normal spleen and thymus lymphocytes in short-term culture release low molecular weight (LMW) DNA protein molecules that have an immunoproliferative effect (polyclonal B cell activation) in vitro. We have determined that the protein-LMW DNA complexes responsible for these effects are nucleosomal constituents of chromatin, since the mitogenically active fractions of these cell-free supernatants contain the constituents of core histones (H3, H2A, H2B, H4) together with LMW DNA (140-180 bp), and since the immunoproliferative effects of these cell-free supernatants could be mimicked by various other nucleoprotein preparations (including calf thymus and chicken erythrocyte nucleosomes). The spontaneous cellular release of cleaved chromatin constituents in vitro can be attributed to a form of programmed cell death termed apoptosis, since the cultured spleen cells exhibited (a) morphologic evidence consistent with this process by electron microscopy, and (b) evidence of intracellular cleavage of chromatin which, like apoptosis, could be blocked with ZnSO4. This resulted in inhibition of the extracellular release of nucleosomal constituents as well as the immunoproliferative effects of the cell-free supernatants. The immunoproliferative effect of nucleosomes released from cells during apoptosis could be responsible for previously observed spontaneous in vitro anti-DNA and anti-histone antibody responses of murine spleen cells, and in vivo in normal lymphoid tissues, resulting in renewed cellular proliferation after cell death. In pathological states, this could result in abnormal polyclonal B cell proliferation and autoantibody formation.

One-off streptococcal serologic testing in young children with recurrent tonsillitis.

OBJECTIVES: Recurrent acute tonsillitis in children under 4 years of age is usually viral, making antibiotic therapy inappropriate and the indication for tonsillectomy uncertain. Identifying those young children with bacterial infections is therefore important. The purpose of this study was to determine whether one-off streptococcal serologic testing is a useful tool in assessing recurrent acute tonsillitis in young children. METHODS: We performed a retrospective study of 45 children (35 male and 10 female) under the age of 4 years who were found by a staff otolaryngologist to have recurrent acute tonsillitis over a 5-year period and had one-off serologic testing for anti-streptolysin O titers and anti-deoxyribonuclease B levels. Data were collected by chart review. RESULTS: Three children (6.7%) had clearly positive titers for either one or both streptococcal antibodies. Children with negative serologic results were significantly less likely to have shown a significant response to antibiotic therapy for their acute episodes (26% versus 100%; p = .026). Nine children (20%) eventually underwent tonsillectomy, all of whom had negative serologic results. CONCLUSIONS: Anti-streptolysin O and anti-deoxyribonuclease B levels may aid clinical evaluation of recurrent acute tonsillitis in young children in differentiating between those cases due to group A beta-hemolytic Streptococcus and those that are viral in origin.

Specificities and genetic characteristics of nucleosome-reactive antibodies from autoimmune mice.

Antinuclear antibodies are present in the serum of individuals with systemic autoimmune diseases such as SLE. Most autoantibodies characterized to date are directed against isolated nuclear molecules such as DNA or histones. We have obtained from spontaneously autoimmune mice six IgG mAb that recognize conformational nucleosome epitopes, but do not react with individual histones or DNA. For three of these mAb, the epitope is at least partially present in the H2A-H2B-DNA nucleosome subparticle, although their binding characteristics differ from those of conventional anti-H2A-H2B-DNA antibodies. All six mAb use VH or Vkappa genes which are recurrently utilized in anti-DNA and other antinuclear antibodies. The V regions of the nucleosome-reactive mAb also contain charged (mostly cationic) residues at sites that are likely to be critical for interaction with nucleosomal antigens. These results suggest that the usage of certain V gene segments in conjunction with suitable V(D)J rearrangements may confer reactivity to nucleosomal antigens. B cells producing such autoantibodies are probably expanded early during the autoimmune process. Somatic mutations in the V regions of nucleosome-reactive mAb may modulate their specificities and result in the acquisition of binding patterns restricted to individual chromatin components such as DNA.

Prospective study of immune response to hydralazine and development of antideoxyribonucleoprotein in patients receiving hydralazine.

To examine the relationship between the immune responses to hydralazine, a drug known to induce systemic lupus erythematosus, and to deoxyribonucleoprotein (DNP) we followed prospectively 21 hypertensive patients treated with hydralazine for the first time. Within one year, antibodies to hydralazine developed in 16 of these patients and anti-DNP in seven of these. In one patient whose serum had a positive antinuclear antibody test prior to treatment, a mild hydralazine systemic lupus erythematosus syndrome developed preceded by rises in the levels of both anti-hydralazine and anti-DNP. Studies by radioimmunoassay on serums of three additional patients, not followed in this study but known to have hydralazine-induced systemic lupus erythematosus, revealed no evidence for either (1) cross-reactivity between anti-DNP and anti-hydralazine or (2) antibodies specific for a hydralazine-DNP complex. In some way, perhaps related to the mechanism by which carrier molecules enhance the immunogenuity of haptens, hydralazine increases the antigenicity of DNP. This effect depends on the development of immunity to hydralazine as well.

Lupus erythematosus cell formation by a monoclonal antibody derived from an autoimmune MRL/Mp-lpr/lpr mouse.

An MRP-2 monoclonal antibody (MoAb) was primarily a product of hybridoma selected by binding to poly(ADP-ribose) from a lupus prone MRL/Mp-lpr/lpr (MRL/l) mouse, and was shown to cross-react with single-stranded (ss) DNA. Detailed examination revealed that MRP-2 MoAb bound to a conformational epitope formed between double-stranded (ds) DNA and total histone: both H3 and H4 were essential for the formation of this conformational epitope with dsDNA. Because of this characteristic of the MoAb, its ability to induce lupus erythematosus (LE) cells was examined in an indirect LE test with peripheral blood of MRL/Mp-+/+ (MRL/n) mice, which develop a mild form of lupus after the age of one year. MRP-2 MoAb was found to induce hematoxylin bodies, LE rosettes and LE cells, but a direct LE test using MRL/n mouse blood did not induce LE cell phenomena. This is the first demonstration of induction of LE cells by a MoAb that binds to dsDNA-histone complexes.

Recent progress in the study of autoantibodies to nuclear antigens.

Autoantibodies to nuclear antigens can now be classified according to their immunologic specificities. They include antibodies that react with DNA, deoxyribonucleoprotein, nuclear histones, and nuclear acidic protein antigens. It has been established that there are several antinuclear antibodies that react with nuclear acidic proteins, and these include antibodies to Sm antigen, nuclear ribonucleoprotein, and SS-A and SS-B antigens. It has also been established that certain systemic rheumatic diseases, such as systemic lupus erythematosus, Sjögren's syndrome, and scleroderma, are characterized by antibodies of some specificities and not of others. Thus, distinct profiles of antibodies to nuclear antigens may be present, and these may be used as diagnostic aids. Further characterization of these specific nuclear antigen-antibody systems may help in unraveling the etiology and pathogenetic mechanims of these diseases.

Autoantibodies and their relation to rheumatic diseases.

The use of tissue culture substrates for immunofluorescence determinations of nuclear, cytoplasmic, and mitotic cell-related autoantibodies has resulted in the delineation of diverse new specificities, whose clinical correlates are now becoming apparent. This review details both major and minor autoantibody specificities, the status of knowledge regarding their target antigens, and the relation of these serologic systems to distinctive rheumatic disease syndromes.

Effect of selective ultraviolet phototherapy on DNA and antinuclear antibody titers in psoriatic patients.

The sera of 21 psoriatics treated by selective ultraviolet phototherapy (SUP) for 1-7 months were screened for IgG- and IgM-anti-DNA antibodies and antinuclear antibodies (ANAs) by standardized ELISA and the indirect immunofluorescence technique. No patients developed IgG-antibodies against native DNA under SUP, but two patients increased their IgM-antibody titers five- and tenfold, respectively. The IgG- and IgM-anti-single-stranded-(ss)DNA antibody titers remained unaltered in 38% and 57% of the patients. In 43% and 24%, respectively, they rose to a maximum of three times their original; and in 20% they decreased to a minimum of 40% of their pretherapeutic titers. After 1 month therapy no patient had produced ANAs, but all three patients showing ANAs before therapy had increased titers (one titer step). These remained on the elevated level or were even further increased by one-titer step during progressive therapy. Two patients out of 14 developed low titers of IgM-(1:20) or IgA-(1:40)ANAs against deoxyribonucleoprotein (DNP), initially after 3 months of irradiation; in one of them IgG-ANAs (titer 1:10) against DNP were additionally formed after 6 months of therapy. Our results suggest that lesions in DNA and DNP generated by SUP trigger an immune response to nuclear antigens.

[Antibodies against deoxyribonucleoproteins in circulating immune complexes in the blood of patients with autoimmune diseases]. / Protilátky proti deoxyribonukleoproteinu v cirkulujících imunitních komplexech a sérech nemocných s nekterými autoimunitními chorobami.

In 40 patients with various autoimmune diseases antibodies against desoxyribonucleoprotein (DNP) were assessed by enzyme immunoanalysis (ELISA) in serum and after dissociation of the isolated precipitate of circulating immune complexes (CIC) in the presence of polyethylene glycol. The results indicate that antibodies against DNP are not specific for systemic lupus erythematosus (SLE) and can be detected in serum and in particular in CIC in various autoimmune conditions. In SLE they may be important for evaluation of the activity of the disease, in particular if estimated concurrently in serum and in CIC.

[Physiological significance of specific immunoglobulins in regulating steroidogenesis in adrenal cortex cells]. / Fiziologicheskoe znachenie spetsificheskikh immunoglobulinov v reguliatsii steroidogeneza v kletkakh korkovogo veshchestva nadpochechnikov.

The data obtained suggest the existence of physiological immunoglobulin mechanisms regulating the functions of the cells including hormone--producing ones. Serologically identical antigens were revealed both in the blood and the extracts from adrenocortical cell nuclei of intact rats. Apart from that, autoantibodies to deoxyribonucleoprotein (DNP) of adrenocortical cells were found in the blood sera of normal animals. Immunoglobulins G (ig G) against adrenocortical cell nuclei, DNP and the nuclei partially devoid of DNP, were produced. The specific IgG were shown to stimulate the steroidogenesis in target cells. The penetration of the specific antibodies into the target cell nuclei in vivo was proved. The data obtained support the hypothesis of the nuclear mechanisms of antibody--caused cytostimulation.

Lupus erythematosus latex tests compared with the immunofluorescence method for antinuclear factor.

Two commercially available lupus erythematosus (LE) latex tests were compared against positive antinuclear antibody (ANF) sera of known titers. The Lederle SLE Latex Test Kit was found to be more specific and relatively more sensitive, particulary with high ANF titers, than the Hyland LE Test Kit. The latex test is a rapid, simple method which, when positive, can be suggestive of systemic lupus erythematosus (SLE) or other collagen disease. However, at present this test cannot replace the immunofluorescence method for detecting ANF. Where there is any clinical suggestion of SLE or a related condition, all negative results should be tested by immunofluorescence methods.

Characterization of antinuclear antibodies induced in rabbits by rinderpest virus infection.

Rabbits infected with the L strain of rinderpest virus (RV) produced high titres of antinuclear antibodies (ANA) which reached a maximum two weeks after inoculation but rapidly disappeared by 6-8 weeks. These ANAs reacted with HeLa cells by indirect immunofluorescence test resulting in a homogeneous nuclear fluorescence. In order to investigate the target antigens of ANAs, the effects on the nuclear fluorescence pattern of pretreating HeLa cells were examined: DNase 1 treatment resulted in a decrease in the fluorescence whereas no changes were evident after RNase A treatment. Some group of sera showed decreased fluorescence in the cells from which histones were acid extracted, but other groups did not change in fluorescence. Sera which had failed to react with acid extracted cells gave positive fluorescence following histone reconstitution. The results indicate that DNA and nucleohistone are the major target antigens for ANAs. In addition, antibodies against nucleoli and extractable nuclear antigens were induced in some rabbits.