Differential expression of DRw52-like determinants detected by monoclonal antibodies

The reactivity of three monoclonal antibodies (MoAb) directed against DRw52-like determinants was studied in relation to the reactivity of an anti-DR MoAb using fluorescence-activated cell sorter (FACS) analysis. The MCS-7 MoAb reacted with all DRw52+ cells and in addition with DR2+, DR4+, and a DR7+ cell. Both the I-LR2 and the 7.3.19.1 MoAb reacted with DR3+, DR5+, and DRw6+ cells only. However, whereas the 1-LR2 MoAb reacted strongly with all those cells compared with the anti-DR MoAb, the 7.3.19.1 MoAb reacted strongly with DR3+ cells only, and somewhat less with DR5+ and DRw6+ cells. The implications of this for the location of DRw52-like determinants on DR beta chains is discussed.