PRESENTATION OF ENDOGENOUS ACETYLCHOLINE-RECEPTOR ANTIGEN TO A SPECIFIC CD4(-CELL LINE BY A TRANSFECTED B-CELL LINE() T)

Currently, the limited supply and stability of some human autoantigens pose formidable difficulties in characterizing patients' T cells spec ific for them; recombinant preparations may contain bacterial contamin ants, and synthetic peptides have arbitrarily chosen start and stop po ints. In order to provide a stable antigen source with naturally proce ssed epitopes, a full-length acetylcholine receptor (AChR) alpha subun it construct was transfected into B-lymphoblastoid cell lines (B-LCL). Expression was much easier to detect at the mRNA level than the prote in level. Nevertheless, this transfectant also stimulated alpha T-cell lint that recognized the alpha 149-156 region in the context of HLA-D R4 at high sensitivity. The responses were specific both for the antig en transfected and for the presenting HLA-DR allele. This study thus c onfirms the potential of autologous B-LCL expressing natural epitopes in the context of HLA class II molecules for characterizing establishe d T-cell lines, and perhaps also for initiating new ones.