Q.73 The principle of immunization was first explained by
(A) Edward Jenner (B) Elie Metchnikoff
(C) Louis Pasteur (D) Robert Koch
Edward Jenner first explained the principle of immunization through his pioneering smallpox vaccination in 1796, establishing the concept of using a milder related strain for protection. This foundational work predates other scientists’ contributions to immunology.
Immunization Principle Defined
Immunization works by introducing a harmless antigen (like weakened virus) to trigger protective antibodies and memory cells without causing disease. Jenner’s 1796 cowpox vaccination demonstrated this: milkmaids exposed to cowpox resisted smallpox.
This active immunity concept revolutionized medicine, reducing smallpox deaths from millions annually to zero by 1980 (eradicated).
Correct Answer: (A) Edward Jenner
In 1796, Jenner inoculated 8-year-old James Phipps with cowpox pus, then exposed him to smallpox—Phipps remained immune. Published as “Inquiry into the Cause and Effects of the Variolae Vaccinae” (1798), this established vaccination as deliberate immunization using related milder pathogens.
Jenner’s work coined “vaccine” from Latin vacca (cow), proving cross-protection between cowpox and smallpox.
Why Not the Other Options?
Option (B) Elie Metchnikoff
Metchnikoff (1845-1916) discovered phagocytosis (1883) and cellular immunity, earning Nobel with Ehrlich (1908). His work explained innate immunity mechanisms post-Jenner, not the immunization principle itself.
Option (C) Louis Pasteur
Pasteur developed rabies (1885) and anthrax vaccines using attenuated (weakened) live bacteria, building directly on Jenner’s concept. His germ theory (1860s) and pasteurization preceded, but immunization principle credit goes to Jenner (1796).
Option (D) Robert Koch
Koch (1843-1910) formulated postulates for disease causation (1884), isolated TB/cholera bacteria. His work proved pathogens cause disease (enabling vaccines), but he didn’t develop or explain immunization—focused on etiology, not prevention.
Historical Timeline Table
| Scientist | Year | Key Contribution | Relation to Immunization |
|---|---|---|---|
| Jenner | 1796 | Cowpox → smallpox vaccine | First explained principle |
| Pasteur | 1885 | Attenuated rabies vaccine | Applied Jenner’s concept |
| Koch | 1884 | Disease postulates | Proved causation |
| Metchnikoff | 1883 | Phagocytosis discovery | Explained mechanism |
Exam Relevance
Common MCQ in NEET-PG, CSIR NET Life Sciences testing immunology history. Remember: Jenner = vaccination pioneer (smallpox); others advanced theory/mechanisms later.
