AP BIOLOGY

Detailed explanation-1: -Thymosin stimulates the development of T cells. Throughout your childhood years, white blood cells called lymphocytes pass through the thymus, where they are transformed into T cells.

Detailed explanation-2: -Once the T lymphocytes recognise their specific antigens, they proliferate and differentiate into one of several effector T lymphocyte subsets. Effector T lymphocytes interact with host cells (rather than the pathogen) to carry out their immune function. T lymphocytes use co-receptors to bind to the MHC molecules.

Detailed explanation-3: -T cell activation and proliferation requires three stimulation signals, antigenic stimulation via the T cell receptor (TCR), co-receptor signalling from professional antigen presenting cells via CD28, and cytokine stimulation primarily driven by interleukin (IL)-2. Stimulation of the TCR alone results in anergy.

Detailed explanation-4: -Abstract. T-cell growth factor (TCGF), also known as interleukin-2, is a small glycoprotein which provides a necessary signal for the proliferation of activated T cells (Morgan et al., 1976; Gillis and Smith, 1977).