Kunio Okudaira

Spontaneously enhanced in vitro immunoglobulin synthesis by B cells in systemic lupus erythematosus

Abstract In vitro immunoglobulin (Ig) synthesis was studied in peripheral blood lymphocytes (PBL) from patients with systemic lupus erythematosus (SLE) (SLE-PBL) in the presence or absence of pokeweed mitogen (PWM). In the presence of PWM, IgM and IgG syntheses were reduced in SLE-PBL, while in the absence of PWM, IgG synthesis was enhanced when compared with normal PBL although IgM synthesis was not significantly augmented. Preincubation and time course studies suggested that the enhancement of IgG synthesis in SLE is not due to the serum factors. The coculture experiments using separated T- and B-rich fractions indicated that reduced Ig synthesis in the presence of PWM may be the result of impaired T- and B-cell functions in SLE, and that raised Ig synthesis in the absence of PWM will be the result of primary B-cell activation. These results suggested that B cells in SLE-PBL are primarily activated and produce Ig without the aid of T cells.

Detection of Antilymphocyte Antibody with Two-Color Method in Systemic Lupus Erythematosus and Its Heterogeneous Specificities against Human T-Cell Subsets

The two-color method originally described by Van Rood et al. (Van Rood, J. J., A. Van Leeuwen, and J. S. Ploen. 1976. Simultaneous detection of two cell populations by two-color fluorescence and application to the recognition of B-cell determinants. Nature (Lond.). 262: 795-797) for the typing of homologous leukocytic antibodies, D-region was used for the detection of antilymphocyte antibody (ALA) in systemic lupus erythematosus. In this method, surface immunoglobulin-bearing cells were identified with fluorescein isothiocyanate-labeled anti-immunoglobulin and nuclei of killed cells were stained with ethidium bromide. Therefore, cell type (T or B) of the target cells can be identified without fractionating them. ALA was detected in 87% of lupus sera and had a preferential reactivity with T cells. Its major immunoglobulin class was shown to be immunoglobulin (Ig)M. The subspecificity of ALA was further analyzed using fractionated T-cell subsets as target cells. When T lymphocytes were separated into Fc receptor-bearing (Tgamma) and lacking (Tgamma[-]) cells, 64% of ALA showed preferential reactivity with Tgamma cells and 14% with Tgamma(-) cells. The remainder had no selective reactivity against Tgamma or Tgamma(-) cells. Tgamma cells were shown to have suppressor activity, whereas Tgamma(-) cells were indicated to contain helper cells. The above finding was in agreement with the observation that treatment of T cells with ALA that preferentially react with Tgamma cells considerably enhanced immunoglobulin synthesis in vitro, whereas treatment of T cells with ALA reactive with Tgamma(-) cells clearly suppressed the formation of immunoglobulins. Treatment of ALA with no selective reactivity showed variable effects on in vitro immunoglobulin synthesis. These results indicate that ALA in lupus have heterogeneous specificities against human T-cell subsets.

Interstitial pneumonitis in autoimmune MRLlpr mice and its treatment with cyclosporin A

Age-associated changes of anti-double-stranded (ds) DNA antibodies, anti-single-stranded (ss) DNA antibodies, and serum immune complex concentrations were studied in MRL/lpr mice. All anti-ds DNA antibodies, anti-ss DNA antibodies, and immune complexes began to be detected in the sera of MRL/lpr mice aged 8 to 13 weeks and increased remarkably after 17 weeks of age. Almost no pathological findings were observed histologically in the lungs of MRL/lpr mice aged 8 weeks but interstitial pneumonitis became evident at 14 weeks of age. Peribronchial and perivascular lymphocyte infiltrations were seen in the lungs of 14-week-old MRL/lpr mice and became more severe at 21 weeks of age. Oral administration of cyclosporin A to 15-week-old MRL/lpr mice markedly prolonged their life span. The lungs of 44-week-old MRL/lpr mice given cyclosporin A showed few pathological findings except for minimal perivascular lymphocyte infiltration.

Effect of antilymphocyte antibody in systemic lupus erythematosus on in vitro Ig synthesis

Abstract The effect of systemic lupus erythematosus (SLE) serum on Con A-induced suppressor T cells was studied in in vitro Ig synthesis. Active SLE sera containing IgG antilymphocyte antibody (ALA) specific for Tγ markedly inhibited the suppressor T-cell activity, whereas either IgM ALA specific for Tγ or any Ig classes of ALA specific for Tγ(−) lymphocytes did not significantly affect the suppressor T-cell activity when compared with IgG Tγ-specific ALA. Other factors possibly present in SLE sera affecting suppressor T-cell activity were also examined in in vitro Ig synthesis assays. Aggregated human IgG used as a substitute for immune complexes inhibited Con A-induced suppression of IgG synthesis in a dose-dependent manner. However, their inhibitory rates were far less than those with active SLE sera containing IgG Tγ-specific ALA. Corticosteroids also strongly inhibited Con A-induced suppressor T-cell activity. In lupus serum the most inhibitory activity was present in IgG (7 S) fraction and removal of IgG from the sera by anti-human IgG-coated beads resulted in the loss of the inhibition against Con A-induced suppressor T-cell activity. These results suggested that the main inhibitory factors contained in active SLE sera for Con A-induced suppressor T-cell activity are the IgG type of Tγ-specific ALA and that other types of ALA may not contribute significantly. Circulating immune complexes and corticosteroids, if present in SLE sera, seemed to play a minor role in the inhibition of suppressor T-cell activity.

Heterogeneity of antilymphocyte antibody in SLE and its correlation with disease activity.

The cytotoxic activities of individual lupus sera were demonstrated against T gamma cells, T gamma (-) cells and B cells. Immunoglobulin classes were also determined in these antilymphocyte antibodies (ALA) in SLE. T gamma-specific ALA and B-cell-specific ALA were almost equally distributed as regards IgG-dominant type, mixed IgG and IgM type and IgM dominant type, while IgM dominant type was predominant in T gamma (-)-specific ALA. Only the IgG type of T gamma-specific ALA among these ALA was significantly associated with clinical parameters, including hypocomplementemia, elevated immune complex levels and high anti-double-stranded (ds) DNA titres. Serial studies on ALA in a typical case of SLE were performed. Active clinical signs were associated with elevated cytotoxicities of IgG type of T gamma-specific ALA and with relatively low cytotoxicities of the IgM type, whereas after massive corticosteroid therapy, these signs disappeared in tact with the reduction in cytotoxic activities of IgG type of the ALA and the relative rise in cytotoxicities of IgM type of the ALA. These results suggested that IgG class of T gamma-specific ALA seemed to play a major role among several types of ALA in SLE.

Inhibition of Tγ Rosette Formation by the Sera from Patients with Systemic Lupus erythematosus

The cytotoxic activities of lupus sera were measured against IgG Fc-receptor-bearing T lymphocytes (Tγ cells) and T lymphocytes lacking this receptor [Tγ (––) cells], and the activities were compared with the inhibitory activities of the sera for the formation of rosettes (Tγ rosettes) between T lymphocytes and ox erythrocytes sensitized with IgG antibody. The cytotoxic activities of the sera against both Tγ and Tγ(––) cells well correlated with their Tγ rosette inhibitory rates. Also, the cytotoxic activities after the removal of IgM antibodies strongly correlated with the inhibitory rates. Among them, the highest correlation was observed between IgG Tγ-specific cytotoxic antibodies and Tγ rosette inhibitory rates of the sera. Gel filtration, ultracentrifugation, pepsin digestion, and reduction and alkylation of the sera revealed that main inhibitory activities were contained in IgG fractions. These results suggested that IgG Tγ-specific antibody suppressed Tγ rosette formation and might contribute to the reduction of Tγ cell number in patients with systemic lupus erythematosus.