The cell type most often invaded by HIV is a(n):
a. Eosinophil
b. Cytotoxic T cell
c. Natural killer cell
d. Helper T cell
e. B cell

Verified step by step guidance

1. Step 1: Understand the role of each cell type listed in the options. Eosinophils are primarily involved in combating parasitic infections and allergic reactions.
2. Step 2: Cytotoxic T cells (also called CD8+ T cells) are responsible for killing virus-infected cells but are not the primary target of HIV infection.
3. Step 3: Natural killer (NK) cells are part of the innate immune system and help destroy infected or cancerous cells, but they are not the main cells infected by HIV.
4. Step 4: Helper T cells (also called CD4+ T cells) play a central role in coordinating the immune response and are the primary cells that HIV targets and invades because the virus binds to the CD4 receptor on their surface.
5. Step 5: B cells produce antibodies but are not the main target of HIV infection. Therefore, the correct answer is the cell type that HIV most often invades, which is the Helper T cell.

Key Concepts

HIV Target Cells

HIV primarily infects cells that express the CD4 receptor, which the virus uses to enter the cell. The main target is the helper T cell (CD4+ T cell), a crucial immune cell that coordinates immune responses. Understanding which cells HIV invades helps explain the immune system's weakening during infection.

Helper T Cells (CD4+ T Cells)

Helper T cells are a subset of lymphocytes that play a central role in activating and directing other immune cells. They express the CD4 receptor, making them susceptible to HIV infection. Their depletion leads to impaired immune function, characteristic of AIDS.

Immune Cell Types and Functions

Different immune cells have distinct roles: eosinophils combat parasites, cytotoxic T cells kill infected cells, natural killer cells provide innate immunity, and B cells produce antibodies. Recognizing these functions helps differentiate which cells HIV targets and why.