HLA-D activity in lymphocyte subcellular fractions
It is generally agreed that primary MLR between two histoincompatible lymphocytes requires the presence of cell-bound D antigens (either fresh or frozen viable cells) as stimulator. The authors have previously reported positive primary MLRs in cultured rat lymphocytes in the presence of histoincompatible Fm or SE. Their data indicate that Fm and SE exhibit D-locus specificity by initiating both primary MLR and a secondary response resulting in a 'PLT' phenomenon. Primed lymphocytes respond vigorously at 24 hr when challenged with Fm or SE from the priming cell.