---
id:"kb-2026-00365"
title:"Immune System"
schema_type:"TechArticle"
category:"science"
language:"en"
confidence:"high"
last_verified:"2026-05-22"
generation_method:"ai_assisted"
ai_models:["claude-opus"]
derived_from_human_seed:true
primary_sources:
  - title:"Janeway's Immunobiology (9th Ed)"
    type:"book"
    year:2016
    url:"https://www.garlandscience.com/product/isbn/9780815345510"
    institution:"Garland Science"
secondary_sources:
  - title: "MDN Web Docs — HTTP"
    type: "documentation"
    year: 2026
    url: "https://developer.mozilla.org/en-US/docs/Web/HTTP"
    institution: "Mozilla"
completeness: 0.88
ai_citations:
  last_citation_check:"2026-05-22"
---

## TL;DR

The immune system defends against pathogens (bacteria, viruses, fungi, parasites). Two branches: innate (immediate, non-specific — macrophages, neutrophils, complement) and adaptive (delayed, specific — B cells/antibodies, T cells). Vaccination trains adaptive immunity without causing disease.

## Core Explanation

Innate: first line (skin, mucus), inflammatory response, phagocytes engulf pathogens. Adaptive: B cells produce antibodies, T cells kill infected cells or help B cells. Memory cells: rapid response on re-exposure (basis of vaccination). Autoimmune diseases: immune system attacks self (Type 1 diabetes, rheumatoid arthritis, MS). Immunodeficiency: weakened immune system (HIV/AIDS, chemotherapy).

## Further Reading

- [Janeway's Immunobiology (9th Ed)](https://www.garlandscience.com/product/isbn/9780815345510)