IMMUNOLOGY

Detailed explanation-1: -The antigen is a peptide fragment generated by antigen-presenting cells when they degrade the foreign protein. To be recognized by a T cell, the antigen must bind a protein called the Major histocompatibility complex (MHC). Cytotoxic T cells recognize antigen bound to MHC protein type 1.

Detailed explanation-2: -There are two main types of T-cells: Helper T-cells stimulate B-cells to make antibodies and help killer cells develop. Killer T-cells or cytotoxic T-cells directly kill cells that have already been infected by a foreign invader.

Detailed explanation-3: -CD8+ T cells, known as cytotoxic T cells, recognize antigens presented by MHC I molecules, which, in combination with CD80 or CD86 interaction, will result in activation and killing of infected or malignant cells [219, 220].

Detailed explanation-4: -The molecules on the APC that present the antigen are called major histocompatibility complexes (MHC). There are two types of MHC: MHC class I and MHC class II. MHC class I presents to cytotoxic T cells; MHC class II presents to helper T cells.

Detailed explanation-5: -Each T cell has a unique T cell receptor (TCR) that recognizes a specific antigen. TCRs recognize an antigen when they bind with major histocompatibility complex (MHC) molecules on the surface of other cells.

Detailed explanation-6: -Class I MHC presentation of exogenous antigens.