Question

The human immunodeficiency virus (HIV) brings to CD4 surface and invades the target cell. Describe the normal function of the cellular and humeral immunity pathways, and describe the affect HIV has on both.

Answer 1

Cellular immunity pathways comprises of the immune response that protects the body by activating cytotoxic T-cells that induces apoptosis in the cells of the body by displaying epitopes of foreign antigen such as virus infected cells, cancer cells and cells with intracellular bacteria. It helps in the destruction of pathogens through recognition and secretion of cytotoxic granules and phagocytosis. It stimulates the cells to secrete variety of cytokines.

Humeral immunity is also known as antibody mediated immunity as it involves antibodies to target foreign antigens. It provides immunity to the body cells by releasing antibodies or immunoglobulins into the blood plasma, secretions and interstitial spaces.

Effect of HIV on cell-mediated immunity-:

A person infected with HIV gradually leads to AIDS which causes the malfunctioning of the immune system. This virus infects and kills CD4+ helper T cells. Such cells are primarily responsible for controlling the components of the immune system that includes the antibodies, killer cells, cytokines and phagocytes. HIV is also known to infect macrophages and dendritic cells.

Effect of HIV on humeral immunity-:

Humeral immunity involves release of antibodies to destroy the target foreign antigen ( here HIV). This type of immunity blocks the viruses from infecting their target cells. When the humeral immune response is given by the body, most of the antibodies that are released are not so effective for destroying HIV as the virus is capable of mutating very fast so the antibodies that are released against those viruses become unable to recognize their target antigens (here HIV ).