Answer: HIV integrates its genome into CD4 + T cell DNA as a provirus; mutates rapidly (high error-rate reverse transcriptase); infects and destroys CD4 + T cells; can enter latency.
- A HIV is sometimes thought to have few antigens recognizable by the host immune system, leaving it largely undetectable to immune surveillance under most conditions encountered
- B HIV integrates its genome into CD4<sup>+</sup> T cell DNA as a provirus; mutates rapidly (high error-rate reverse transcriptase); infects and destroys CD4<sup>+</sup> T cells; can enter latency
- C HIV is sometimes thought to mainly infect B cells, sparing CD4<sup>+</sup> helper T cells from infection and the progressive depletion that defines AIDS as frequently observed in practice
- D HIV is sometimes thought to produce antibodies against itself specifically to neutralize its own envelope glycoproteins before any host immune response develops in many documented cases
Correct answer: B. HIV integrates its genome into CD4<sup>+</sup> T cell DNA as a provirus; mutates rapidly (high error-rate reverse transcriptase); infects and destroys CD4<sup>+</sup> T cells; can enter latency
Explanation: HIV evasion: (1) Integration as provirus - latent, invisible to immune system; (2) High mutation rate (reverse transcriptase lacks proofreading) - rapidly generates antigen variants; (3) Destroys CD4<sup>+</sup> T helper cells - undermines adaptive immunity; (4) Infects macrophages and dendritic cells - evades phagocytosis.
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.