Immunopurification and insertion into liposomes of native and mutant H-2Kb: quantification by solid phase radioimmunoassay.

To study the interaction between T cells and isolated H-2Kb, we developed protocols for the immunopurification of the molecule from monoclonal anti-H-2Kb immunoadsorbent columns and for its insertion in lipid vesicles. Patterns of reactivity of two anti-H-2Kb monoclonal antibodies (mAb) (20-8-4 and Y3) on H-2 recombinant and H-2Kb mutant mice indicated that mAb Y3 reacted with all six mutant forms of H-2Kb tested. Binding competition studies indicated that Y3 and 20-8-4 recognized distinct epitopes of H-2Kb. A solid phase radioimmunoassay was established using these two mAb to monitor H-2Kb activity in detergent containing cell lysates, after immunopurification, and after insertion into liposomes. About 70% of H-2Kb activity could be eluted from anti-H-2Kb-immunoadsorbents in the presence of 3 M NH4SCN and octyl glucoside (pH 7.4). A procedure of liposome formation combining gel dilution and dialysis yielded liposomes bearing H-2Kb molecules which could inhibit antibody plus complement cytolysis and could stimulate in vivo primed T cells to generate cytotoxic T lymphocytes in vitro. The present protocol can be extended to immunopurify and obtain H-2Kbm1 bearing liposomes.