This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Secondary allograft rejection is mediated by 
Select and explain. 
A. Memory cells, B. Antibodies, C. Immune complexes, D. None of the above
A: Memory cells
Answer: A: Memory cells 
Explanation: Answer- A. Memory cellsAfter hlperacute rejection, transplantation of a second gfaft, which shares a significant number of antigenic determinants with the first one, results in a rapid (2 - 5 days) rejection. It is due to presence of T-lymphocyte sensitized during the first graft rejection(memory cells).