Selective inhibitory effect of anti-L^dantibodies on Sn⁺ macrophage-mediated presentation of β-gal–derived MHC class I-restricted peptide (A) and on processing of β-gal protein and peptide presentation (B) to CD8 T lymphocytes. Responder cell priming, restimulation, and kill assays were performed as described in Fig 4. Cultures for responder lymphocyte restimulation contained Sn⁺ spleen macrophages and antigen (□). In some cultures, anti–H-2L^d (•) or control anti–H-2K^d (⧫) MoAbs were added. Negative controls included antigen (β-gal or its peptide) and responder cells only (▵). Means and standard deviations from 3 independent assays are shown. Data points without SD represent values for which the SD was smaller than 1.