Man a special creature

HIV/AIDS Human immunodeficiency virus ( HIV ) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS), a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive.          i.             HIV infects vital cells in the human immune system such as helper T cells (specifically CD4 + T cells), macrophages , and dendritic cells .        ii.             HIV infection leads to low levels of CD4 + T cells through three main mechanisms: a.        First, direct viral killing of infected cells; b.       second, increased rates of apoptosis in infected cells; and c.        killing of infected CD4 + T cells by CD8 cytotoxic lymphocytes that recognize infected cells. When CD4 + T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic What'