DNA restriction fragment length polymorphisms characteristic for Dw subtypes of DR2.

DNA restriction fragment length polymorphisms (RFLP) can be easily demonstrated in DNA of cells expressing different DR specificities when class II cDNA probes are used for hybridization. Previous studies of DR4+ homozygous typing cells (HTCs) carrying different Dw subtypes, however, detected no RFLP correlating with subtypes. In contrast, we report here Southern blotting studies of DR2+ HTCs carrying different subtypes which showed RFLP patterns characteristic for each subtype, using both DR beta and DQ beta probes and several restriction enzymes. The RFLP between subtypes of DR2 was, however, appreciably lower than that found between DR specificities.