Answer: CD4 + T helper cells.
- A B cells
- B CD8<sup>+</sup> T cells
- C CD4<sup>+</sup> T helper cells
- D Macrophages only
Correct answer: C. CD4<sup>+</sup> T helper cells
Explanation: HIV (Human Immunodeficiency Virus) specifically infects and destroys CD4<sup>+</sup> T helper cells, which are crucial coordinators of the immune response. Loss of CD4<sup>+</sup> T cells leads to AIDS, leaving the body vulnerable to opportunistic infections.
An antibody is Y-shaped, with two identical antigen-binding sites at the tips of the variable regions - each shaped to recognise one specific antigen - while the constant (Fc) region at the base is recognised by immune cells to trigger further responses.
Concept context
Innate and adaptive immunity, B cells, T cells, antibodies, vaccines, and immune disorders. Critical for NEET.