Host Immune Response to Infections

Immune Evasion by Pathogens

The human immune system is a powerful defense mechanism against infections. However, pathogens have evolved sophisticated strategies to evade immune surveillance, ensuring their survival within the host.

Mechanisms of Immune Evasion

• Antigenic Variation: Many pathogens, such as influenza virus and Trypanosoma brucei, alter their surface antigens to evade immune recognition.
• Inhibition of Phagocytosis: Bacteria like Mycobacterium tuberculosis produce virulence factors that prevent engulfment by macrophages.
• Immune Suppression: HIV depletes CD4+ T cells, weakening the adaptive immune response.
• Intracellular Survival: Some pathogens, including Listeria monocytogenes, escape the host's lysosomal degradation by residing inside cells.

Impact on Host Health

Immune evasion leads to chronic infections, increased severity, and difficulties in vaccine development. Understanding these mechanisms helps in designing targeted therapeutics.

Future Research & Therapeutic Approaches

Innovative strategies, such as immune checkpoint inhibitors and monoclonal antibodies, are being explored to counteract pathogen evasion and restore effective immune function.