Final answer:
HIV targets cells in the immune system with specific binding sites, like CD4+ T cells, which it infects and destroys, leading to weakened immunity. The virus's rapid mutation also helps it evade immune detection, complicating vaccine development.
Step-by-step explanation:
HIV, the virus that causes AIDS, only infects certain cells within the immune system because it specifically targets cells that have the proper binding sites which are compatible with the virus, such as helper T cells (CD4+ T cells), macrophages, and dendritic cells.
These cells play a crucial role in the body's response to infection by acting as a bridge between the innate and adaptive immune response. HIV is able to enter these cells, use their machinery to reproduce, and ultimately destroys them.
This leads to a decrease in CD4+ T cell levels, weakening the immune system and making the body more vulnerable to opportunistic infections. Complicating matters further, HIV frequently mutates, changing its surface antigens, which helps it evade the immune response and renders the development of a vaccine highly challenging.