MEDICAL PHYSIOLOGY

Detailed explanation-1: -The helper T cell also secretes cytokines, which can interact with the B cell and provide additional stimulation.

Detailed explanation-2: -Helper T cells secrete cytokines that help B cells differentiate into plasma cells. These cells also help to activate cytotoxic T cells and macrophages. Regulatory T cells (or Tregs) help to suppress the immune system. Lymphocytes are immune cells found in the blood and lymph tissue.

Detailed explanation-3: -Th1 helper cells lead to an increased cell-mediated response (primarily by macrophages and cytotoxic T cells), typically against intracellular bacteria and protozoa. They are triggered by the polarising cytokine IL-12 and their effector cytokines are IFN- and IL-2.

Detailed explanation-4: -Naïve CD4+ T cells engage MHC II molecules on antigen-presenting cells (APCs) and become activated. Clones of the activated helper T cell, in turn, activate B cells and CD8+ T cells, which become cytotoxic T cells. Cytotoxic T cells kill infected cells.