IMMUNOLOGY

Detailed explanation-1: -Taken together, these observations suggested a model of HIV pathogenesis in which viral-mediated destruction of CD4+ helper T cells results in impaired immunity to pathogenic agents typically restricted by T-cell-mediated immunity, and ultimately, the emergence of one or more fatal OIs.

Detailed explanation-2: -HIV binds to the CD4 molecule on the surface of helper T-cells and replicates within them. This results in destruction of CD4+ T-cells and leads to a steady decline in this population of T-cells.

Detailed explanation-3: -The HIV virus destroys part of the immune system, specifically a type of white blood cell called a T lymphocyte or T cell (or CD4 helper lymphocyte cell, or CD4 cell.

Detailed explanation-4: -Helper T-cells are a type of immune cell. They’re one of the main types of cells produced by your thymus. Helper T-cells sense when there’s an infection in your body. They activate other immune cells to fight the infection. These T-cells are an important part of your adaptive immune response.