Functionality of donor leukocytes in recipients of different sexes. These are the same experimental conditions as those described in Figure 1. The left bars of each column are survival percentages of male recipient mice and right bars are those of female recipient mice after the completion of all three S180 IP challenges. The female recipients display a lower survival in all mismatched groups. The percent survival for each group is as follows: male 100% versus female 67% for the sex-mismatch, male 83% versus female 33% for MHC-mismatch, and male 67% versus female 17% for sex- and MHC-mismatch.