Analysis of cytotoxic T cell precursor frequencies directed against individual HLA-A and -B alloantigens

We describe here a limiting dilution analysis to determine cytotoxic T lymphocyte precursor (CTLp) frequencies against individual HLA-A or -B antigens. This assay is reproducible and showed that the CTLp frequency of an individual remains stable with time. Significant variations in CTLp frequency against the same alloantigen were found in different individuals and even in monozygotic twins, showing that these differences were not (completely) genetically determined. Within an individual, a wide range of CTLp frequencies can be found against different allo-antigens. Serologically cross-reactivity seems not to interfere in this assay. This LDA is a practicable tool for a systematic analysis of CTLp response against selected individual HLA-A or -B antigens and can be used for the selection of HLA mismatched donors for transplantation patients