Cellular and serological subtypes of HLA-DR2.

HLA-DR2 and its subtypes were investigated in informative families and unrelated Caucasoid individuals. Serological and cellular typing indicate that DR2 can be divided into DR2 long and DR2 short (sh), each of which can be further subdivided either by HLA-D typing or primed lymphocyte reagents. DR2 long includes Dw2, Dw12 and a new subtype temporarily called D-GEN. The cellular equivalent of DR2sh was recognized by mixed lymphocyte culture (MLC) practised in a family (family FJO); the typing cell individualized was termed FJO. The reactivity of this cell is compared with similar DR2sh varieties described in other laboratories: MN2 (Bach, Minneapolis), AZH (Brautbar, Jerusalem), DB9 (Layrisse, Caracas). The distinction between FJO, MN2 and AZH is not clear, suggesting the existence of shared epitopes; DB9 cells gave typing responses only in family FJO but typed no one else in our panel. Primed cellular reagents FJO anti Dw2 and Dw2 anti FJO when tested against DR2 subtypes support the distinction between DR2 long and DR2sh. The use of these subgroups of DR2 in functional studies, the biochemical analysis of their class II molecules, the pattern of their DNA recombinant fragments and the correlation established with some diseases will be discussed, since they further contribute to the cleavage between DR2 subtypes.