Richard H. Weisbart

Specificity of anti-nucleoside antibodies in systemic lupus erythematosus

The titer of IgG antinucleoside antibodies in the sera of 162 individuals was determined by an enzyme-linked immunosorbent assay. The nucleosides used in the assay were adenosine, cytidine, guanosine, and thymine-riboside conjugated to human serum albumin. The specificity of IgG antinucleoside antibodies was indicated by appropriate reduction in antibody binding after solid-phase adsorptions of antibody with specific immobilized nucleoside conjugates. Disease-associated increases in serum IgG antibodies to cytidine and guanosine but not to adenosine or thymine-riboside occurred in patients with systemic lupus erythematosus (SLE). The epitope density of nucleosides in the conjugates and differences in the sensitivity of each nucleoside assay were not responsible for disease-associated IgG antinucleoside antibody responses. These findings support a possible pathogenic role for cytidine and guanosine as antigens or crossreactive antigenic determinants in some patients with SLE.

Neutrophil migration inhibition factor from T lymphocytes (NIF-T): a new lymphokine.

Abstract Neutrophil migration inhibition factor produced by peripheral blood lymphocytes and that produced by a unique T-lymphoblast cell line were characterized and appeared to be the same. Both factors were remarkably heat stable 35,000 to 45,000 dalton glycoproteins that were resistant to diisopropyl fluorophosphate, and both reversibly inhibited neutrophil migration. This neutrophil migration inhibition factor appears to be produced selectively by T lymphocytes and is distinct from previously described mediators that inhibit neutrophil migration.

Effect of corticosteroids on serum antinuclear antibodies in man.

The effect of prednisone on serum levels of IgG antibodies to viral and bacterial antigens was measured and compared to its effect on IgG antibodies to nuclear antigens in 8 patients with systemic lupus erythematosus. Prednisone at 15-80 mg/day (mean 55 mg/day) for 14-30 days (mean 19 days) lowered the serum IgG by an average of 22% (p less than 0.005). An even greater reduction in IgG antinuclear antibodies occurred (mean 43%, p less than 0.001) including responses to double stranded DNA, single stranded DNA, and the nucleosides, adenosine, guanosine, cytidine and thymine riboside. In contrast, there was no alteration in serum IgG antibody levels to influenza virus vaccine and pneumococcal vaccine antigens. These results suggest that prednisone has a selective effect on the expression of autoimmunity which may, in part, be responsible for its clinical efficacy in systemic lupus erythematosus.

Neutrophil migration inhibition factor from T lymphocytes (NIF-T): Partial purification by antibody affinity chromatography and further characterization

Abstract Neutrophil migration inhibition factor from T lymphocytes (NIF-T) is a newly recognized glycoprotein that is distinguished from other migration inhibition factors by its molecular weight, isoelectric point, and resistance to inactivation by diisopropyl-fluorophosphate (DFP). NIF-T was purified approximately 1700-fold by antibody affinity chromatography. Two major peaks of NIF-T activity corresponding to molecular weights of about 50,000 and 25,000 were resolved by gel filtration chromatography. The predominant molecular weight species was approximately 25,000 as determined by gel filtration chromatography in the presence of urea and by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The larger (50,000) component probably represents a dimer or aggregate of the smaller molecular weight component. NIF-T was shown to have an isoelectric point of approximately pH 4.6. Treatment with bacterial neuraminidase shifted the isoelectric point to about pH 4.8, suggesting the presence of sialic acid.

The fine specificity of IgG antiguanosine antibodies in systemic lupus erythematosus.

The antigen specificity, isotype, and subclass of antinuclear antibodies may be related to their pathogenicity in systemic lupus erythematosus (SLE). Our laboratory found that IgG antibodies that bound the nucleoside, guanosine, occurred frequently in SLE patients. In contrast, sera from healthy subjects contained IgM but not IgG antiguanosine antibodies. The present studies were designed to characterized the fine specificity of IgG antiguanosine antibodies in SLE and compare them with IgM antiguanosine antibodies in normal sera. Serum antinuclear antibodies from six healthy subjects and six SLE patients were isolated by affinity binding to guanosine and measured by an enzyme-linked immunosorbent assay (ELISA). IgM in normal sera, and both IgM and IgG in SLE sera bound guanosine. IgM antiguanosine antibodies in normal sera were polyspecific and bound other nucleosides and 1-methylguanosine but not denatured DNA (ssDNA). In contrast, IgG antiguanosine antibodies from the SLE patients bound guanosine and ssDNA but not other nucleosides or 1-methylguanosine. SLE IgM antiguanosine antibodies had the same fine specificity and bound guanosine and ssDNA but not any of the other nucleosides. These results suggest that SLE IgG and IgM antiguanosine antibodies have fine specificity in contrast to the polyspecific IgM antibodies in normal sera. In addition, subclass analysis indicated that all SLE patients had either IgG1 or IgG3 subclass of antiguanosine antibodies that bind complement. Characterizing the isotype, subclass, and fine antigen specificity of antiguanosine antibodies should assist in evaluating their potential pathogenicity in SLE.

Further purification of neutrophil migration inhibition factor from T lymphocytes (NIF-T): evidence that NIF-T and leukocyte inhibitory factor (LIF) are immunologically distinct.

Neutrophil migration inhibition factor from T lymphocytes (NIF-T) purified by antibody affinity chromatography and gel filtration chromatography was radioiodinated and identified as a 26,000-MW protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). NIF-T was identified by elution of biological activity from gel fractions and selective adsorption of a radioiodinated mediator by HL60 cells differentiated in the presence of dimethyl sulfoxide (DMSO) to develop receptors for NIF-T. A goat neutralizing antibody for NIF-T neutralized and immunoprecipitated migration inhibition activity in the conditioned medium from Mo T-lymphoblast cells and human peripheral blood lymphocytes (PBL) cultured with concanavalin A (Con A), but not from RPMI 1788 B-lymphoblast cells with leukocyte migration inhibitory factor (LIF) activity. These studies distinguish NIF-T both chemically and immunologically from LIF.

Effect of methylprednisolone on the production of neutrophil migration inhibition factor by T lymphocytes (NIF-T)

Glucocorticoids may suppress cell-mediated immunity by inhibiting lymphocyte mediator production or reducing the responsiveness of target cells to these mediators. Our laboratory recently described a newly recognized T-lymphocyte mediator, neutrophil migration inhibition factor from T-lymphocytes (NIF-T). In this report we assessed the effect of glucocorticoids on NIF-T activity. Methylprednisolone (MP) at concentrations as low as 10-7 M inhibited NIF-T activity from peripheral blood lymphocytes (PBL) in response to staphylococcal protein A (SPA) and concanavalin A (Con A). However, MP at concentrations as high as 10-4 M did not after the responsiveness of neutrophils to NIF-T. Therefore, the effect of MP on NIF-T activity was due to inhibition of mediator production. The effect of MP on NIF-T production was reversible in 24 hours. This finding is consistent with the clinical observation that alternate day therapy does not suppress cell-mediated immunity. Serum taken from a patient as early as one hour after oral administration of 100 mg of prednisone inhibited NIF-T production in vitro; serum obtained at 48 hr after prednisone had no measurable effect on NIF-T activity, In addition. MP inhibited NIF-T production by previously activated lymphocytes.