Biomedical subjects

M Takeno

Publications and source records attributed to M Takeno.

39 records · Page 3Linked to original sources

PubMedDate not supplied

Aberrant expression of Fas ligand on anti-DNA autoantibody secreting B lymphocytes in patients with systemic lupus erythematosus: "immune privilege"-like state of the autoreactive B cells.

BACKGROUND: Fas/Fas ligand (FasL) system has been assigned a pivotal role in the development and maintenance of peripheral tolerance, and mice with defects in their Fas/FasL system develop lupus-like symptoms. In this study we examined FasL expression of peripheral blood lymphocytes in patients with systemic lupus erythematosus (SLE). METHODS: We assessed FasL mRNA and protein expression by reverse transcription (RT)-PCR and immunoblotting and immunocytochemical staining, respectively, in patients with SLE. Anti-DNA antibody secreting B cells were purified using biotin labeled DNA and streptavidin-bead. RESULTS: Expression of FasL protein was not or very weakly detected in freshly isolated PBMC in normal individuals. In contrast, freshly isolated SLE PBMC exhibited the enhanced expression of FasL protein without in vitro stimulation. Not only purified T cells but also purified B cells expressed FasL on their cell surface spontaneously. In addition, freshly isolated anti-DNA autoantibody secreting B cells express FasL without in vitro stimulation. CONCLUSION: The results suggest that autoreactive B lymphocytes which aberrantly express FasL may kill Fas+ immunoregulatory T lymphocytes. Thus aberrantly expressed FasL may facilitate escape of the autoreactive B cells from the immune tolerance system, and may contribute to the sustained secretion of autoantibodies in patients with SLE.

Adolescent↗

PubMedDate not supplied

Preferential expression of B7.2 (CD86), but not B7.1 (CD80), on B cells induced by CD40/CD40L interaction is essential for anti-DNA autoantibody production in patients with systemic lupus erythematosus.

OBJECTIVE: B7 (CD80/CD86) molecules are over-expressed in patients with SLE. However, it is not clear whether CD80/CD86 molecules are involved in the pathogenic autoantibody production specifically or in the polyclonal antibody production in human SLE. The present study was carried out to characterize B7 molecules on B cells in autoantibody production. METHODS: Expression of costimulatory molecules was analyzed by RT-PCR and two-color immunofluorescence staining. Purified B cells were co-cultured with T cells in the presence of anti-costimulatory molecule antibody. RESULTS: Excessive expression of CD86 and CD80 molecules was evident on freshly isolated B cells in patients with SLE. Normal B cells did not express CD86 molecules spontaneously and expressed it after co-culture with activated T cells. CD86 expression on normal and SLE B cells induced by the activated T cells was inhibited by the addition of anti-CD40L into the cell culture. Furthermore, CD40L expression on T cells upon activation was enhanced in SLE patients. Anti-DNA antibody production by SLE B cells in the presence of activated T cells was markedly inhibited by anti-CD86, but not anti-CD80. Anti-CD86 treatment inhibited polyclonal Ig and anti-SS-A antibody production of SLE B cells, suggesting the preferential involvement of CD86 in polyclonal antibody production. CONCLUSION: SLET T cells express CD40L excessively, and the CD40/CD40L pathway is involved in the CD86 over-expression of SLE B cells; thus T cell abnormality is at least partially involved in B cell hyperactivity. Enhanced CD86 expression of B cells by CD40L is essential for polyclonal antibody production.

Adolescent↗

PubMedDate not supplied

Selective suppression of resting B cell function in patients with systemic lupus erythematosus treated with cyclophosphamide.

The immunological function of patients with inactive systemic lupus erythematosus (SLE) receiving chronically administered, low-dose cyclophosphamide (CY) together with prednisolone (PSL) was compared with that of inactive patients receiving PSL alone. A striking selective suppression of "genuine" resting, but not "partially" or "fully" activated, B cell function was noted in the patients receiving PSL + CY as measured by Staphylococcus aureus Cowan I (SAC)-induced proliferative responses by Percoll-separated small resting B cells of high density; the small resting B cells sedimenting in a high density fraction were more responsive to SAC in patients treated with PSL alone than those in normal controls. However, the spontaneous proliferation and spontaneous secretion of immunoglobulins by peripheral blood B cells were elevated in both the patient groups. The proliferative responses to phytohaemagglutinin and concanavalin A by T cells were not significantly different between both patient groups. The data indicate that the genuine resting B cells may be the major target for the CY effect in SLE, and thus such selective suppression may help explain the efficacy of CY and PSL together in treating SLE.

Adult↗