IMMUNO 440 Lecture Notes - Lecture 25: Transplant Rejection, Alloimmunity, Mhc Class I
Document Summary
Graft rejection first investigated by skin transplants between inbred strains of mice: Autograft/autologous graft: graft from one site to another on same person. Allograft/allogeneic graft: graft between unrelated, genetically disparate individuals. Migration of donor apcs from allograft to draining lns. Donor mhc alloags recognized by alloreactive host cd4 and cd8 t-cells (na ve memory cells can be activated) o. Alloreactive effector cells migrate back to allograft; mediate rejection of foreign invader o o o o. Can be inhibited by depletion of apcs from allograft. By phagocytosis of donor apcs migrating to dln. Frequency of host t-cells activated via indirect pathway much lower than direct pathway o. Continuous exposure of host immune response to donor alloags via indirect pathway results in gradual amplification of alloreactive effector t-cells; leads to chronic rejection o. Once t cells are activated o o o. T-cell dependent process; allograft into t-cell deficient animal not rejected.
