🛡️ Your Immune System: The Army Inside You
📝 Last reviewed: August 2026
Layer 1 — barriers: skin, mucus, stomach acid and friendly bacteria physically block most invaders before anything starts.
Layer 2 — innate immunity: the fast, general response: fever slows microbes, inflammation brings immune cells to the site, and phagocytes (macrophages, neutrophils) eat invaders. This acts within minutes to hours.
Layer 3 — adaptive immunity: the precise, slower response: B cells make antibodies that neutralise specific pathogens; T cells kill infected cells and coordinate. This takes days on first exposure — and remembers.
Memory: after an infection or vaccine, memory B and T cells stay for years. That is why you rarely catch chickenpox twice, and why vaccines work: they create memory without the disease.
What weakens it: chronic sleep deprivation, stress, poor nutrition, smoking, and conditions like HIV that destroy T cells. Sleep is when much of the immune memory is consolidated.
Metchnikoff's discovery: in 1882 Élie Metchnikoff watched phagocytes engulf bacteria — the birth of cellular immunology. He won the Nobel Prize in 1908, and his classic book Immunity in Infective Diseases is in our free library.
💬 Visitor comments
Comments are public, moderated by the community spirit — be kind. We may remove spam or offensive posts.