Explain6 marksChallenge
A patient receives a skin graft from an unrelated donor. The graft is rejected after 10 days. Six months later, the patient receives a second skin graft from the same donor, which is rejected after 3 days.
Explain how the patient's immune system distinguishes between self and non-self antigens and how the difference in rejection times occurs. In your answer, refer to the roles of macrophages, B-lymphocytes (including plasma cells), T-helper cells, T-killer cells, and memory cells.