GENOMIC MHC HAPLOTYPING OF MUTANT-CELL LINES USING A NOVEL MARKER

The aim of this study was to characterize MHC mutant cell lines by stu dying haplospecific markers within the MHC and specifically in the 250 kilobase (kb) region between the HLA B and TNF loci. This region has been difficult to define because of the lack of appropriate markers. S pontaneous MHC mutants were isolated after immunoselection with an ant i-HLA A2 monoclonal antibody and complement. Ten mutants were characte rized using serological or allelic and genomic DNA markers within the HLA A to HLA DQ region ot the MHC. Most mutants lost at least the 3 me gabases of DNA from HLA A to HLA DQ viz the whole haplotype carrying H LA A2. Variants which have lost either HLA A alone or HLA A and HLA B were also found. The results show that it is possible to map the exten t of the deletion between HLA B and TNF. Haplospecific scanning patter ns for the CL region appear particularly useful.