Which of the following cell types are the most significant in mediating graft rejection?

• A. B lymphocytes
• B. Cytotoxic T lymphocytes (CD8+ T cells)
• C. Basophils
• D. Eosinophils

Answer: (B)

Verified step by step guidance

1. Understand the context of the question: Graft rejection occurs when the immune system recognizes a transplanted organ or tissue as foreign and attacks it. This process is mediated by specific immune cells.
2. Review the roles of the immune cells listed: B lymphocytes, Cytotoxic T lymphocytes (CD8+ T cells), Basophils, and Eosinophils. Each has a distinct function in the immune response.
3. Focus on Cytotoxic T lymphocytes (CD8+ T cells): These cells are critical in graft rejection because they directly attack and destroy cells that display foreign antigens on their surface, such as those from a transplanted organ.
4. Eliminate the other options: B lymphocytes are involved in antibody production, which is less directly involved in graft rejection. Basophils and Eosinophils are primarily associated with allergic reactions and parasitic infections, respectively, and are not significant in graft rejection.
5. Conclude that Cytotoxic T lymphocytes (CD8+ T cells) are the most significant cell type in mediating graft rejection due to their ability to recognize and kill foreign cells.