HIV infection primarily targets which immune cells?

• A. B cells expressing CD19
• B. Neutrophils
• C. CD4+ T cells
• D. Dendritic cells

Answer: (C)

HIV primarily targets CD4+ T helper cells because they express the CD4 receptor that the virus uses to attach, with entry also requiring a co-receptor such as CCR5 or CXCR4. Once inside, the virus replicates and eventually leads to loss of these cells. CD4+ T cells are the conductors of the immune response, coordinating activation of B cells to produce antibodies, CD8+ cytotoxic T cells to kill infected cells, and macrophages. Their depletion disrupts multiple arms of immunity, allowing opportunistic infections and cancers to take hold, which is the hallmark progression to AIDS if untreated. Other cells like B cells, neutrophils, or dendritic cells are not the primary targets, though dendritic cells can be infected to some extent and can aid virus spread.