HIV reservoirs in the body are primarily located in which tissue?

• A. Blood plasma
• B. Bone marrow
• C. Muscle
• D. Lymph tissue

Answer: (D)

HIV reservoirs persist mainly in lymphoid tissues because these sites house large populations of long-lived memory CD4+ T cells where the virus can exist in a latent, integrated form. Lymph nodes, spleen, and gut-associated lymphoid tissue provide a rich environment for these cells, allowing proviral DNA to remain for years even under antiretroviral therapy. The architecture of lymph tissue, with germinal centers and extensive immune cell trafficking, creates a sanctuary where infected cells can survive longer and occasionally reactivate, maintaining the reservoir. In contrast, circulating virus in blood plasma reflects free virus rather than a stable, latent reservoir; muscle is not a known major reservoir, and bone marrow can harbor some infected cells but does not represent the primary reservoir.