HLA-DPA1 and infection: We purified MHC-bound complexes of two independent infections (62 and 116 x106 cells), using sequential immunoaffinity purification with anti-HLA-DR (LB3.1), anti-HLA-DP (B7/21), and anti-HLA-ABC (W6/32) antibodies, collecting three immunoprecipitated samples, one from each antibody, per biological replicate infection.