INFLUENCE OF RECOMBINANT INTERLEUKIN‐2 AND α‐ AND γ‐INTERFERONS ON THE INDUCTION OF NOVEL CLASS I ANTIGENS

Abstract

Previous results obtained in our laboratory showed that novel class I antigens, closely related to HLA-A (TM antigen related to HLA-A9 and GO antigen related to HLA-A24), were expressed on activated HLA-A9 or HLA-A24 peripheral blood lymphocytes (PBL), whatever activation factor was used [mitogenic stimulation (PHA, PWM, Con A), EBV transformation or alloactivation], but not on resting T and B lymphocytes. These antigens were also expressed on HLA-A9 or HLA-A24 common acute lymphoblastic leukaemias (cALL) and some 'immature' chronic lymphocytic leukaemias (B-CLL), but not in hairy cell leukaemias (HCL), most of the B-CLL, acute myeloblastic leukaemias (AML) and acute myelomonoblastic leukaemias (AMoL). In order to investigate the regulation mechanisms of these novel class I antigens, PBL and different leukaemic cell types were treated in vitro with recombinant IL-2 (rIL-2) and alpha and gamma-interferon (rIFN). Our results showed that without previous activation, but after culture with rIL-2, TM and GO antigens could be induced in HLA-A9 or HLA-A24 PBL and enhanced in HLA-A9 or HLA-A24 B-CLL cases, whereas no expression was found in HLA-A9 or HLA-A24 HCL, T-ALL, AML or AMoL. After culture with rINFs, the expression of TM and GO antigens could be induced on HLA-A9 PBL and all HLA-A9 leukaemic cell varieties. Our results support the hypothesis that the expression of class I antigens is induced at an early stage of the cell cycle.