DNA Restriction Fragment Length Polymorphism of the Human Class II Genes as Analyzed by Southern Blotting Technique

Abstract

The human HLA-D region class II antigens each consist of two non-covalently linked trans-membrane glycoprotein subunits: an α heavy chain of 32–35 kd and a β light chain of 28–30 kd [1]. They are encoded by a complex multigene family consisting of several loci within the major histocompatibility complex on chromosome 6 [1]. Their products, which are primarily represented on B cells, monocytes and activated T cells, participate in several cellular immune functions. These include antigen presentation and cell—cell recognition. They are also associated with susceptibility/resistance to some diseases [1]. There are at least three distinct class II allelic series - HLA-DR, BR and DQ - all detectable by molecular and serological assays [2]. A fourth serologically defined class II system has been called “SB” (now DP) because it is thought by some to correspond to the antigens defined by primed lymphocyte typing [5]. In addition, there are the HLA-D specificities which are defined by mixed lymphocyte culture testing. Most of these specificities correlate closely with HLA-DR in Caucasoids but not in Negroids and Mongoloids [3]. The precise relationship between these “MLC determinants” and the molecules described above has not yet been established.

These studies were supported by the Cancer Research Campaign (KH), the Medical Research Council (FG, JA), the Nuffield Foundation (HF), the Leukaemia Research Fund (CN) and the Multiple Sclerosis Society (AVG)