title: IgA-specific helper activity of T alpha cells in human peripheral blood.
abstract: A subpopulation of human T lymphocytes that express receptors of immunoglobulin A (T alpha cells) was separated by a FACS using FITC-conjugated human IgA myeloma protein in order to determine whether they have helper activity for in vitro immunoglobulin synthesis in comparison with a T alpha cell population separated by rosette formation using PTN-ORBC conjugated with MOPC-315 mouse IgA myeloma protein. FACS-separated T alpha cells have IgA specific helper activity, whereas rosette-separated T alpha cells have polyclonal helper activity for in vitro immunoglobulin synthesis in PWM-stimulated B cells. The polyclonal helper activity observed in rosette-separated T alpha cells might be due to contamination of non-T alpha cells in the T alpha cell fraction. It is concluded that purified T alpha cells in normal human peripheral blood show IgA-specific helper activity in vitro.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D000921:Antibody-Producing Cells / Q000166:cytology; D002417:Cattle; D002455:Cell Division; D002469:Cell Separation; D005434:Flow Cytometry; D006801:Humans; D007070:Immunoglobulin A; D009194:Myeloma Proteins / Q000276:immunology; D011961:Receptors, Fc; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*; D014302:Trinitrobenzenesulfonic Acid / Q000276:immunology
chemical_list: D007070:Immunoglobulin A; D009194:Myeloma Proteins; D011961:Receptors, Fc; D014302:Trinitrobenzenesulfonic Acid