This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cells and Tissues of Immune System, Subject name: Pathology
[{'content': 'CD4 count refers to - \nSelect and explain. \nA. T helper cells, B. B cells, C. Cytotoxic cells, D. Both B And T Cells', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., T helper cells o Helper T-cells - CD4 positive.o Cytotoxic T-cells and suppressor T-cells - CD 8 positive,o Based on function CD4 helper T cells are divided into-1. Effector CP4 helper Tcells# Functions are :-A. By TH1 cellsActivate macrophagesDelayed hypersensitivityCell mediated immunityKilling of intracellular microbes.e.g. tuberculosis and leprosyDestruction of target cells by-Activate CDS T cells to become cytotoxic cells.Activate NK cellsB By TH2 celtsi) Activate B cells to develop into antibody producing plasma cells - facilitate synthesis of antibodies.2. Memory CD4 helper T cells# Retain the antigenic affinity of the originally activated T cells and are used to act as later effector cells during a second immune response.", 'role': 'assistant'}]