Complement in skin grafting in mice.

The role of haemolytic complement activity in the rejection of skin homografts in mice was studied. Two co-isogenic lines of mice were used, which are only known to differ in one respect. One line (B10.D2 new) possesses haemolytic complement activity, while the other line (B10.D2 old) lacks such activity. Both lines of mice rejected CF-1 and C57B1/6J skin grafts at essentially the same rate. It was therefore concluded that the presence or absence of haemolytic complement activity does not affect the rejection of skin homografts in mice. To determine if B10.D2 new and B10.D2 old line are histocompatible, skin grafts were exchanged between members of both lines. Although B10.D2 new line mice accepted B10.D2 old line skin grafts without exception, the reverse situation did not always obtain. The possible role of Hc, as well as alternative reasons for the observed histoincompatibility, are discussed.