Question

Compare how cell-mediated immunity is essential for elimination of pathogen and destruction of tumour cells and relate the importance of DCcross presentation in this context

Answer 1

Cell-mediated immunity is an immune response that does not involve antibodies. cell-mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to antigen.  CD4 cells also known as helper T cells provide protection against different pathogens. Naive T cells, which are immature T cells that have yet to encounter an antigen, are converted into activated effector T cells after encountering antigen-presenting cells (APCs). Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection.

The process of cross presentation is necessary for immunity against most tumors and viruses that do not readily infect antigen-presenting cells, but rather intracellular tumors and viruses that infect peripheral tissue cells. Cross presentation is also required for the induction of cytotoxic immunity by vaccination with protein antigens, for example, tumour vaccination.