Antiribosomal P protein antibody in human systemic lupus erythematosus reacts specifically with activated T cells.
We examined the presence of the epitope recognized by antiribosomal P protein antibody (anti-P) on the cell surface of human immunocompetent cells. Highly purified CD4+ and CD8+ T cells, and B cells from normal healthy individuals were reacted with affinity-purified IgG anti-P, and were stained with FITC-conjugated F(ab)2, fragment goat anti-human IgG, followed by analysis on flow cytometry with gating for viable cells by propidium iodide staining. The presence of an epitope that is antigenically related to the carboxyl-terminal 22-amino-acid sequence of ribosomal P protein was not demonstrated on the surface of fresh CD4+ and CD8+ T cells, or fresh B cells. However, the expression of the ribosomal P epitope was induced on CD4+ and CD8+ T cells after activation with immobilized anti-CD3, whereas the epitope was not expressed on activated B cells. These results indicate that anti-P is an antilymphocyte antibody, which reacts specifically with activated T cells but not with resting T cells or B cells, suggesting possible direct effects of anti-P on the immune dysregulation in systemic lupus erythematosus.
Hirohata
S
S
Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan. shunsei@med.teikyo-u.ac.jp
Nakanishi
K
K
D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002478:Cells, Cultured; D000939:Epitopes / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D019169:Jurkat Cells; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D015800:Protozoan Proteins; D012269:Ribosomal Proteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D000939:Epitopes; C064601:L12E protein, Trypanosoma cruzi; D015800:Protozoan Proteins; D012269:Ribosomal Proteins