169. AIDS is caused by a human retrovirus that kills:
A. B lymphocytes
B. Lymphocytes stem cells
C. CD4-positive T-lymphocytes
D. CD8-positive T-lymphocytes

Introduction

AIDS (Acquired Immunodeficiency Syndrome) is a disease caused by HIV (Human Immunodeficiency Virus), a retrovirus that attacks and weakens the immune system. One of the key features of HIV infection is its ability to specifically target certain immune cells, leading to a gradual breakdown of the immune response. In this article, we explore the primary target of HIV and how its destruction leads to the clinical manifestations of AIDS.

HIV and its Target: CD4-Positive T-Lymphocytes

CD4-positive T-lymphocytes, often referred to as helper T cells, play a critical role in the immune system by assisting other immune cells in recognizing and attacking pathogens like bacteria, viruses, and fungi. These cells are essential for the proper functioning of the immune system.

HIV primarily infects and kills these CD4-positive T-lymphocytes, leading to a severe reduction in the immune system’s ability to defend the body. The progressive loss of these cells is the hallmark of AIDS, leaving individuals vulnerable to opportunistic infections and certain cancers.

Why CD4-Positive T-Lymphocytes?

HIV has a high affinity for the CD4 receptor on the surface of these T-cells. After binding to the receptor, the virus enters the cell, replicates, and eventually causes the death of the host cell. Over time, as more and more CD4-positive T-cells are destroyed, the immune system weakens, leading to the development of AIDS.

Answer to the Question

Given the understanding of HIV’s effects on the immune system, the correct answer to the question:

AIDS is caused by a human retrovirus that kills:

C. CD4-positive T-lymphocytes

Conclusion

The destruction of CD4-positive T-lymphocytes by HIV is the primary cause of immune system failure in AIDS. This loss of helper T-cells severely weakens the body’s ability to fight infections, making HIV infection a major global health concern. Understanding the virus’s target helps in the development of treatments aimed at preserving immune function and preventing progression to AIDS.