T cell allorecognition and endogenous HLA-B27-bound peptides in a cell line with defective HLA-B27-restricted antigen presentation.

The B2702+ lymphoblastoid cell line NW is unable to present at least some HLA-B27-restricted viral antigens to T cells. This defect was genetically inherited, and was suggested to be related to the nature of the HLA-B27 binding peptides reaching the endoplasmic reticulum in these cells (Pazmany et al., J. Exp. Med. 1992. 175: 361). In the present study 17 of 19 HLA-B27-specific alloreactive cytotoxic T lymphocyte clones recognizing the B2702 subtype on other cells also lysed NW cells. Only two cytotoxic T lymphocyte clones failed to lyse NW while efficiently killing other B2702+ cell lines. The high-performance liquid chromatography profiles of the B2702+ bound peptides extracted from NW cells was similar, but not identical, to those from two other cell lines. These results indicate that the HLA-B27-bound peptide repertoire in NW cells is not fundamentally different from those in other B*2702+ cells. Our data argue against gross differences in peptide processing or transport as being responsible for the defective presentation of particular HLA-B27-restricted viral antigens to T cells, but do not rule out distinct presentation of some endogenous peptides. Differences in the capacity to present certain peptides could cause differential susceptibility among HLA-B27+ individuals to ankylosing spondylitis.