| Description |
The studies involving cell-mediated immunity in germfree animals are conflicting. It the guinea pig, skin allograft rejection and delayed hypersensitivity reactions are depressed. In contrast, skin allograft rejection is accelerated in the germfree rat, while in the mouse, it is comparable to that of the conventional mouse. The effect of the germfree environment on the survival time of first and second set skin allografts and xenografts was obtained by comparing germfree (BALB/c x C57BL/10) F1 female mice with age-matched conventional controls for "strong" (H-2), "moderate" (non H-2), and "week" (H-Y) alloantigenic incompatibilities, and germfree BALB/c female mice with their age-matched conventional counterparts for xenoantigenic incompatibilities. In the "strong" alloantigentic system, using C3Hf female skin allografts, there was no significant difference between germfree (9.6 ± 0.4 days) and conventional (9.8 ± 0.7 days) mice for the first set median survival times. Second set median survival times were not remarkable different (germfree, 6.4 ± 0.1 day; conventional 6.3 ± 0.3 days). In the "moderate" alloantigenic system, using 129 female skin allografts, the first set median survival time of 15.0 ± 1.4 days for germfree mice was not significantly different from that of 13.5 ± 0.7 days for conventional mice. Second set median survival times were the same for both groups, 6.3 ± 0.1 days. There was no significant difference between first set median survival times for germfree (31.0 ± 4.0 days) and conventional (31.0 ± 3.8 days) mice in the "week" antigenic system, when (BALB/c x C57BL/10) F1 male skin was grafted onto F1 hybrid females. The second set median survival times were not remarkable different (12.6 ± 2.3 days for germfree and 12.8 ± 2.9 day for conventional). In the xenoantigenic system, using Fisher/344 male rat skin xenografts, a median survival time of 7.1 ± 0.2 days for germfree mice was not significantly different from that of 6.8 ± 0.2 days for conventional mice. Second set xenografts for both group were completely destroyed by day 6 following transplantation. Apparently, neither the absence of viable microorganism nor the reduction of lymphoid tissue in germfree mice have an effect on skin allograft and xenograft rejection. |
