THE ROLE OF PASSENGER LEUKOCYTES IN THE ANOMALOUS SURVIVAL OF NEONATAL SKIN GRAFTS IN MICE

The anomalous survival of neonatal C3H skin grafts on CBA mice is correlated with the emigration of passenger leukocytes from the graft vasculature. Thus, newborn homografts whose leukocyte populations are eliminated by X-irradiation or by transient sojourn on an intermediate adult C3H host, do not display prolonged survival. Moreover, the continued presence of the newborn grafts is not requisite to the maintenance of the unresponsive state, an observation consonant with the demonstration that CBA mice bearing long-term neonatal C3H skin grafts are leukocyte chimeras. In contrast, neonatal male C57 skin grafts may persist on C57 females after heavy irradiation of the donor, or after passage on an intermediate adult male host. In addition, tolerance is broken by removal of long-persistant newborn grafts from hitherto unresponsive females, and chimerism is not detectable in female C57 mice tolerant of infant male isografts. Finally, leukocytes of neonatal C3H origin, inoculated subcutaneously into CBA males, may occasionally render these animals unresponsive to subsequent adult C3H skin homografts, whereas those taken from infant C57 males usually sensitize their adult female hosts. Thus, passenger leukocytes are implicated in the extended survival of C3H neonatal homografts on CBA recipients, but not in the persistence of H-Y-incompatible neonatal skin isografts on C57 females

SKIN HOMOGRAFTS: TOLEROGENIC VERSUS IMMUNOGENIC INFLUENCES IN MICE

In strain combinations involving multiple non-H-2 disparities, neonatal skin grafts may survive significantly longer than adult grafts of similar genotype on normal adult hosts, and repeatedly outlive grafts of adult origin on immunosuppressed recipients. Moreover, newborn grafts of long-standing may render their hosts unresponsive to adult skin grafts from the same donor strain. With some H-2-compatible strain combinations in which homozygous neonatal grafts are rejected, F1 hybrid (heterozygous) grafts of similar age not only may survive indefinitely, but also may induce tolerance of subsequent adult parental strain homografts. These tolerogenic and gene dosage effects, although much weaker, can likewise be revealed with H-2-incompatible neonatal skin grafts

Serological Crossreactivity Between H-Y (Male) Antigens of Mouse and Man

Antisera to H-Y (male-specific) antigen were prepared by immunizing female mice with spleen cells from males of the same inbred strain. These antisera were used in mixed hemadsorption and cytotoxicity tests with cells of rats, guinea pigs, rabbits, and humans. The results showed that the H-Y components of all four species are antigenically related to H-Y of the mouse