🦠

Understanding Immune Response to HIV

May 25, 2025

Immune Response to Viruses

Introduction

  • The body’s immune system reacts vigorously to viral infections.
  • White blood cells (WBCs) play a crucial role in this response.

HIV: A Unique Challenge

  • HIV (Human Immunodeficiency Virus) specifically targets helper T-cells, which are essential for mounting an immune response.

Infection Process

  • Attachment and Entry: HIV attaches to and enters helper T-cells.
  • Reverse Transcription: The virus uses an enzyme called reverse transcriptase to convert its RNA into DNA.
  • Integration: The viral DNA integrates into the host cell’s genome.
  • Replication: The infected cell produces HIV proteins and genetic material, leading to the creation of new viruses.
  • Viral Spread: New HIV particles exit the infected cell, leading to a rapid increase in viral load.

Immune System's Response

  • Restriction Factors: Inside infected cells, antiviral proteins attempt to shut down virus production.
  • Antibody Production: White blood cells, including B-cells, produce neutralizing antibodies that bind to HIV, preventing it from infecting healthy cells.
  • Killer T-cells and Natural Killer Cells: These cells attack and destroy infected cells using a protein called perforin.

Initial Success and HIV's Counter-Attack

  • The immune system can temporarily reduce HIV levels through its defenses.
  • HIV's Counter-Strategies:
    • Disabling antiviral proteins in host cells.
    • Constant mutation to evade immune detection.

Consequences of Prolonged Infection

  • Over time, the immune system becomes exhausted:
    • Killer T-cells become activated for too long and stop responding.
    • There is a decline in the production of new helper T-cells.
  • This leads to a state known as AIDS (Acquired Immunodeficiency Syndrome).

AIDS and Its Implications

  • The body becomes immunodeficient, making it vulnerable to infections from otherwise harmless microbes.
  • No Cure for HIV: There is currently no way to completely eliminate HIV from the body.
  • Hidden Reservoirs: If treatment stops, HIV can rebound from these reservoirs.

Treatment Options

  • Antiretroviral Drugs: These can help manage HIV infection, allowing the immune system to recover and maintain functionality.