Figure 1. Graft survival in NK cell depleted recipients. A: 3-week-old (young) Lewis rats were injected twice with a NK cell depleting antibody (3.2.3). Blood was taken and analyzed by flow cytometry for the presence of CD3⁺ and CD161⁺ cells. Intraperitoneal injection of 3.2.3 lead to complete absence of CD161⁺ NK/NKT cells and did not affect cell numbers of CD3⁺CD161^- T cells. FACS data shown are representative for control animals that received an isotypic antibody (NK+) or 3.2.3-treated rats (NK-). B: After injections of either isotyp controls (NK+) or 3.2.3 (NK-) allogeneic penetrating keratoplasty was performed and the grafts were assessed clinically until rejection occurred. Albeit all recipients of both allogeneic groups rejected, animals of group NK- showed a statistically significantly delay of immunological allograft failure (p<0.01). None of the syngeinic controls (groups syn.NK+ and syn.NK-, respectively) rejected. C: NK cells were depleted in 10-week-old (old) Lewis rats (NK-) or isotypic antibody was injected (NK+). NK cell depletion had no effect on graft survival rates.