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Difference Between Innate Immunity and Acquired Immunity — NEET Biology

The main difference between innate and acquired immunity is that innate immunity is a non-specific defense present from birth, while acquired immunity is pathogen-specific and develops after exposure to an antigen. NTA tests the barriers (physical, physiological, cellular, cytokine), types of acquired immunity (active vs passive, humoral vs cell-mediated), and specific examples.

Comparison Table: Innate Immunity vs Acquired Immunity

BasisInnate ImmunityAcquired Immunity
DefinitionNon-specific defense present from birthPathogen-specific defense developed after exposure
SpecificityNon-specific — acts against all pathogens equallyHighly specific — targets particular antigens
MemoryNo immunological memoryHas memory — faster response on re-exposure
Response timeImmediate (0–12 hours)Takes time to develop (days to weeks on first exposure)
ComponentsSkin, mucus, HCl in stomach, neutrophils, macrophages, NK cellsB-lymphocytes, T-lymphocytes, antibodies
BarriersPhysical (skin), physiological (acid, lysozyme), cellular (phagocytes), cytokineHumoral (antibody-mediated) and cell-mediated immunity
InheritanceInherited from parentsNot inherited — acquired during lifetime
TypesFour barriers: physical, physiological, cellular, cytokineActive (infection/vaccination) and passive (antibodies transferred)
Vaccination relevanceNot affected by vaccinationVaccination stimulates active acquired immunity
ExamplesSkin blocking entry, lysozyme in tears, fever responseImmunity after chickenpox, antibodies from mother's milk (passive)

Key Points to Remember

  • Innate immunity includes 4 barriers: physical, physiological, cellular, cytokine (NCERT Ch. 8, Class 12)
  • Acquired immunity has two types: humoral (B-cells produce antibodies) and cell-mediated (T-cells destroy infected cells)
  • Active immunity = body produces own antibodies (long-lasting); passive immunity = pre-formed antibodies received (short-lived)
  • Colostrum (mother's first milk) provides IgA antibodies — example of passive immunity
  • Vaccination is based on the memory of acquired immunity — anamnestic (secondary) response is faster and stronger

NEET Exam Tip

How NTA Tests ThisNTA frequently tests: 'Colostrum provides which type of immunity?' — passive acquired immunity. Also: 'Which barrier of innate immunity includes interferons?' — cytokine barrier. Multi-statement questions mixing innate barriers with acquired immunity types are common. Remember: interferons and complement proteins are part of innate immunity, NOT acquired.

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