# DBT JRF 2022 — Question 54

Exam: DBT JRF 2022 · Section: B · Topic: Microbiology › Virology - HIV & AIDS · Difficulty: Medium

## Question

AIDS is caused by a human retrovirus that kills:

## Options

- **A.** B lymphocytes
- **B.** Lymphocytes stem cells
- **C.** CD4-positive T-lymphocytes
- **D.** CD8-positive T-lymphocytes

## Answer

Option C

## Explanation

HIV target cells: HIV (Human Immunodeficiency Virus, a lentivirus/retrovirus) specifically targets cells expressing the CD4 glycoprotein as its primary receptor: • CD4+ T helper lymphocytes (Tᴴ cells): The primary target; HIV uses CD4 as receptor and CCR5/CXCR4 as co-receptors for entry. • Macrophages and dendritic cells also express CD4 and can be infected. Consequences of HIV infection: • Persistent replication in CD4+ T cells → their gradual depletion. • When CD4+ count falls below 200 cells/μL → AIDS (Acquired Immunodeficiency Syndrome). • Loss of T-helper cells impairs both humoral and cell-mediated immunity → opportunistic infections. Answer: HIV targets and kills CD4+ T-helper lymphocytes.

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