Detection of HLA‐DP serological allodeterminants by the use of radioiodinated DP molecules

Abstract

HLA class II molecules were partially purified from cells of an HLA deletion mutant cell line, LCL721.82, that lost DR and DQ expression but retained DPw2 specificity and labeled with radioactive 125I. The radioiodinated preparation bound to DP-specific monoclonal antibody B7/21 as well as rabbit anti-HLA class II antiserum. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the component involved in these bindings gave, unlike known HLA class II molecules, a sharp and dense band of approximately 60 kDa under nonreducing conditions and a single but diffuse band of approximately 30 kDa under reducing conditions. By screening 401 anti-HLA class II alloantisera, including those distributed in the 9th International Histocompatibility Workshop and also those locally available, eight were found to possess significant binding activity. Specificity analysis of these eight binding-positive antisera on a panel of DP-pretyped HLA homozygous typing cells revealed the presence of two clusters, one corresponding to an allodeterminant associated with DPw1, 2 and 3 and the other to that associated with DPw2 and 4. These two determinants were shown by the sequential binding test to reside on the B7/21-defined HLA class II molecules. Thus, two major conclusions were drawn: two distinct allodeterminants are carried by a single DP molecule; and these serologically detected DP allodeterminants are supertypic to cellularly defined DP allospecificities.

HLA‐DPB1 oligonucleotide typing of a Southwest German Caucasian population

“…They were independently discovered by Shaw and Termijtelen by primed lymphocyte typing (6,7). Serological analysis of DP antigens has been reported (8,9), but it is hampered by the lack of suitable reagents. Cloning of the DPa and DPP genes has allowed the use of restriction fragment length polymorphism analysis as an alternative method (1Cb12).…”

Two sequence dimorphisms of DPB1 define the immunodominant serologic epitopes of HLA-DP

“…There are less common cases showing sera with anti-DP reactivity that can be accounted for only in terms of the DPA1 chain and not the DPB1 chain. We identified three sera in which reactivity against DPA1*0201 could be invoked, although, in addition, the reactivity of these sera was completely consistent with the presence of antibodies reactive with anti-P-001 and anti-P-004 [2,[4][5][6].…”