Production of B cell growth factor by a Leu-7+, OKM1+ non-T cell with the features of large granular lymphocytes (LGL).
The present study reports the characterization of a non-T cell from human peripheral blood which is capable of releasing BCGF. This BCGF-producing non-T cell had a T3-, T8-, Leu-7+, OKM1+, HLA-DR-, Leu-11- surface phenotype and was likely to belong to the so-called large granular lymphocyte (LGL) subset because: after fractionation of non-T cells according to the expression of Leu-7 or HLA-DR markers, it was found in the Leu-7+, HLA-DR- fractions that were particularly enriched in LGL; it co-purified with LGL on Percoll density gradients; and it expressed Leu-7 and OKM1 markers that are shared by a large fraction of LGL. Although co-purified with cells with potent NK capacities, the BCGF-producing cell was not cytotoxic, because treatment of Leu-7+ cells with Leu-11 monoclonal antibody and complement abolished the NK activity but left the BCGF activity unaltered. The factor released by this LGL subset was not IL 1 or IL 2 mistakenly interpreted as BCGF, because: a) cell supernatants particularly rich in BCGF activity contained very little or no IL 1 or IL 2; b) BCGF-induced B cell proliferation was not inhibitable by anti-Tac antibodies (this in spite of the expression of IL 2 receptor by a proportion of activated B cells); and c) BCGF activity was absorbed by B but not T blasts.
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D002469:Cell Separation; D006133:Growth Substances / Q000096:biosynthesis*; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4; D007694:Killer Cells, Natural / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D008222:Lymphokines / Q000096:biosynthesis*; D010641:Phenotype; D013601:T-Lymphocytes
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D006133:Growth Substances; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007375:Interleukin-1; D007376:Interleukin-2; D008222:Lymphokines; D015847:Interleukin-4