Restoring Homeostasis After Infection: Innate and Adaptive Immune Mechanisms

1. Innate Immune Response (Immediate, Non-specific)

• Phagocytosis: Macrophages and neutrophils engulf and destroy pathogens.
• Inflammation: Chemical signals increase blood flow, recruit immune cells, enhance pathogen clearance.
• Natural Killer (NK) Cells: Kill infected and tumor cells without prior sensitization.
• Interferons: Inhibit viral replication, boost immune cell activity.

2. Adaptive Immune Response (Specific, Long-lasting)

• Antibody Production: B cells produce antibodies that bind specific antigens, marking pathogens for destruction or blocking cell entry.
• T Cell Response: Helper T cells activate B cells and cytotoxic T cells; cytotoxic T cells directly kill infected cells.
• Memory Response: Memory B and T cells provide rapid, robust protection upon re-exposure.

These mechanisms cooperate to eliminate pathogens, control infection, and restore internal balance.