Immunity
Innate and acquired immunity, active and passive immunity, antibody structure and vaccination. (Biology › Human Health and Disease, NEET UG syllabus.)
What is Immunity?
The ability of the host to fight against disease-causing organisms conferred by the immune system.
Key points
- Differentiate between innate and acquired immunity with examples.
- Explain the various barriers involved in innate immunity.
- Describe the primary and secondary immune responses.
- Illustrate the structure of an antibody molecule and list its different types with their functions.
Common exam trap
Confusing innate and acquired immunity: Innate is non-specific and present from birth; acquired is specific and develops over time.
Definitions
- Term
Immunity
- Meaning
The ability of the host to fight against disease-causing organisms conferred by the immune system.
- Term
Innate Immunity
- Meaning
Non-specific defense mechanisms that are present from birth and provide immediate protection against a wide range of pathogens.
- Term
Acquired Immunity
- Meaning
Pathogen-specific defense mechanisms that develop after exposure to a pathogen and are characterized by memory.
- Term
Antibody (Immunoglobulin)
- Meaning
A Y-shaped protein produced by B-lymphocytes in response to an antigen, capable of binding specifically to that antigen.
- Term
Vaccination
- Meaning
The process of introducing a vaccine (attenuated/inactivated pathogen or its components) into the body to stimulate an immune response and provide protection against future infection.
- Term
Antigen
- Meaning
Any substance capable of eliciting an immune response, typically a foreign molecule.
Learning objectives
Differentiate between innate and acquired immunity with examples.
Explain the various barriers involved in innate immunity.
Describe the primary and secondary immune responses.
Illustrate the structure of an antibody molecule and list its different types with their functions.
Distinguish between humoral and cell-mediated immunity.
Compare and contrast active and passive immunity, providing examples for each.
Explain the principle and importance of vaccination.
Prerequisites
Basic understanding of cells and tissues.
Knowledge of different types of microorganisms (bacteria, viruses, fungi, parasites).
Familiarity with the concept of proteins and their structure.
Common mistakes
Confusing innate and acquired immunity: Innate is non-specific and present from birth; acquired is specific and develops over time.
Mixing up active and passive immunity: Active means the body makes its own antibodies; passive means receiving pre-formed antibodies.
Misunderstanding the role of B and T lymphocytes: B cells produce antibodies (humoral), T cells directly kill infected cells or regulate immune responses (cell-mediated).
Incorrectly identifying antibody types and their functions (e.g., IgA in secretions, IgG placental transfer, IgE allergy).
Forgetting that vaccination provides active immunity, not passive, as the body produces its own antibodies.
Keywords
Immunity
Innate Immunity
Acquired Immunity
Antibody
Immunoglobulin
B-lymphocytes
T-lymphocytes
Vaccination
Active Immunity
Passive Immunity
Humoral Immunity
Cell-Mediated Immunity
Antigen
Memory cells
Practice preview
Which of the following acts as a physiological barrier in innate immunity?…
easy
An antibody molecule is composed of:…
easy
Vaccination provides immunity by:…
easy