Identification of several functional subgroups of HLA-B27 by restriction of the activity of antiviral T killer lymphocytes.

Anti-Epstein-Barr virus and antiinfluenza A cytotoxic T lymphocytes (CTL) have been used to study the restriction of human antiviral responses by HLA-B27 antigens. Three functional subgroups of HLA-B27 have been clearly distinguished by this "restriction-typing assay". No cross-reaction could be detected between the three subgroups either at the CTL level or at the level of antigen-presenting cells. The cells of subgroup 1 are always positive [M2(+)] when tested in immunofluorescence with a monoclonal B27-specific antibody which divides HLA-B27 into a major M2(+) and a minor M2(-) subgroup. These M2(+) group 1 cells are apparently also HLA-B27W as previously shown by Ivanyi and co-workers using anti-HLA-CTL. Subgroup 2 includes only M2(-) cells. A comparison between this group and the previously described HLA-B27K is not fully conclusive, since two typing cells which were clearly HLA-B27K apparently did not belong to group 2. Only two donors, both of Oriental origin, have been included in subgroup 3. Both of them were "M2 intermediate". These results demonstrate (1) the existence of several functional subgroups of HLA-B27 with an interesting correlation with the M2(+), M2(-), or M2 intermediate phenotypes, and (2) the possibility of using the restriction-typing assay to define such functional subgroups not detected by classical allosera.