This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders), Subject name: Microbiology
Which is concerned with cell mediated immunity 
Select and explain. 
A. B-Lymphocytes, B. T-Lymphocytes, C. Eosinophils, D. Monocytes
B: T-Lymphocytes
Answer: B: T-Lymphocytes 
Explanation: Option 1, 2, 3, 4 Cell-mediated immunity: It is mediated by both activated T helper cells and cytotoxic t cells. Cytokines secreted by Th cells activate various phagocytic cells, enabling them to phagocytose and kill microorganisms. This type of cell-mediated immune response is especially impoant against a host of bacterial and protozoal pathogens. CTLs play an impoant role in killing virus-infected cells and tumor cells. Major Functions of Cell-Mediated Immunity (T Cells) 1. Host defense against infection (especially M. tuberculosis, fungi, and virus-infected cells). 3. Graft and tumor rejection 4. Regulation of antibody response (help and suppression) Humoral immunity: B lymphocytes produces antibodies and conve into plasma cell which are responsible of immunogenic memory