Which virus causes progressive loss of CD4+ T cells leading to AIDS?

Which virus causes progressive loss of CD4+ T cells leading to AIDS?

• A. Cytomegalovirus
• B. Hepatitis C virus
• C. Human immunodeficiency virus
• D. Epstein-Barr virus

Answer: (C)

HIV is the virus that causes AIDS by progressively depleting CD4+ T cells. It attaches to the CD4 receptor on helper T cells and uses a coreceptor (CCR5 or CXCR4) to enter. Inside, it reverse transcribes its RNA into DNA, integrates into the host genome, and produces new virions. Ongoing replication leads to death of infected cells and chronic immune activation, driving a gradual fall in CD4+ T cell numbers and resulting immunodeficiency. When CD4+ T cells become very low, the body loses the ability to mount effective cell-mediated responses, allowing opportunistic infections and certain cancers that define AIDS. The other viruses listed do not cause AIDS by directly eroding CD4+ T cells: CMV is an opportunistic infection in this setting, hepatitis C targets the liver, and EBV primarily infects B cells and is linked to certain lymphomas rather than driving CD4+ T cell loss.

HIV is the virus that causes AIDS by progressively depleting CD4+ T cells. It attaches to the CD4 receptor on helper T cells and uses a coreceptor (CCR5 or CXCR4) to enter. Inside, it reverse transcribes its RNA into DNA, integrates into the host genome, and produces new virions. Ongoing replication leads to death of infected cells and chronic immune activation, driving a gradual fall in CD4+ T cell numbers and resulting immunodeficiency. When CD4+ T cells become very low, the body loses the ability to mount effective cell-mediated responses, allowing opportunistic infections and certain cancers that define AIDS. The other viruses listed do not cause AIDS by directly eroding CD4+ T cells: CMV is an opportunistic infection in this setting, hepatitis C targets the liver, and EBV primarily infects B cells and is linked to certain lymphomas rather than driving CD4+ T cell loss.