Modulation of HLA class II antigen expression by transfection of sense and antisense DR alpha cDNA.

The HLA classII molecules of the human MHC are cellsurface glycoproteins that play a criticalrolein the immune response regulation.At leastthree HLA class II isotypeshave been described (HLA-DR, -DQ, and -DP), each composed of an a and a s chain (1).In addition to conventional HLA classII molecules, the existence of hybrid molecules formed by transcomplementation (hybrid HLA-DQ) and interisotypicpairing (HLA-DRa-DQs) has been previously reported (2,3).In the context of our understanding of immune regulation and HLA classII-linked autoimmune diseases,itisof particularinterestto modify the classII phenotype by creating or suppressing individual specificities .To modulate the expression of class II molecules, human EBV transformed B celllineswere transfectedwith sense and antisense DRa cDNA .We show that quantitativevariationof the DRa chain leads to de novo expression or extinction of the DRa-DQs dimer .