Figure 2.

Attenuation of cytotoxic T lymphocyte (CTL) responses (⁵¹Cr‐release assays performed at day 5 using labelled P815 target cells) in mixed lymphocyte co‐cultures (MLC) using splenocytes pooled from naive BL/6 mice (data to far left in each panel for anti‐BALB/c and anti‐C3H responses) following addition of whole spleen cells (a) or CD4⁺‐enriched splenocytes (b) of skin graft recipients shown in Fig. 1. CTL in cultures stimulated with third‐party cells (C3H) were assayed using C3H Concanavalin A blasts. Data were obtained using individual spleen preparations from all mice shown in Fig. 1, and were then pooled within groups in which mice had accepted/rejected skin grafts (see Fig. 1). In each set of upper/lower panels the added cells from grafted recipients were treated with either rabbit complement alone, or anti‐CD45.1/anti‐CD45.2 with rabbit complement. *P < 0·05 compared with equivalent recipients with rejected grafts.