Active = "Antigen entered" (the body makes the antibody).
Passive = "Antibody entered" (preformed antibodies are given).
Natural = normal life process; Artificial = medical needle (injection).
Step 1: Understanding the Question:
We need to match the four classifications of acquired immunity (List-I) with their corresponding clinical or biological examples (List-II).
Step 2: Key Concept and Approach:
Let us define the categories of acquired immunity:
- Active Immunity: The host's own body produces antibodies in response to antigen exposure.
- Passive Immunity: Ready-made antibodies are transferred directly to the host.
- Natural: Occurs through natural physiological processes (infection or breast milk).
- Artificial: Induced through medical interventions (vaccines or antibody serum).
Step 3: Detailed Explanation:
• A. Natural active immunity -- IV. Chickenpox: Getting infected with chickenpox naturally stimulates the host's B-cells to produce active antibodies and memory cells.
• B. Natural passive immunity -- I. Colostrum: Colostrum contains maternal IgA antibodies that are naturally transferred to the newborn without the baby's immune system creating them.
• C. Artificial active immunity -- II. Vaccination: Injecting a harmless antigen (vaccine) artificially forces the body to actively generate its own antibodies.
• D. Artificial passive immunity -- III. Anti rabies serum: Administering preformed antibodies (anti-rabies immunoglobulin) artificially provides immediate, passive protection.
• This corresponds to the sequence: A-IV, B-I, C-II, D-III.
Step 4: Final Answer:
The correct match is A-IV, B-I, C-II, D-III, which is Option (B).
