History of Immunity

The History of Immunization

In attempt to prevent diseases, 15th-century Chinese practiced of the custom of inhaling dried powders of smallpox crust to gain protection, but the inoculation of human smallpox material was found to be hazardous Edward Jenner observed that people who caught cowpox rarely contracted smallpox. In 1796 he induced cowpox in a young boy and later tried to infect the boy with smallpox, but immunity provoked by the cowpox virus was effective against smallpox.

Louise Pasteur discovered in 1879 that neglected cultures of the bacteria that cause chickens cholera lost much of their ability to cause the disease, whereas fresh cultures failed to infect chicken previously inoculated with old cultures. The introduction of dead or attenuated (weakened) microbes into the body to develop resistance to disease is called Vaccination is used against such bacterial diseases as cholera, diphtheria, and viral infectious including hepatitis B, measles, poliomyelitis and rabies.

The work of Jenifer and Pasteur marked the beginning of the field of immunity, emphasizing the role of antibodies, proteins produced by cells and released into the bloodstream, as the major agents of immunity. Russian biologist Elie Metchinkoff (1845 - 1916) developed the cellular theory of immunity, in which phagosytes, the body's scavenger cells, are the major detectors of foreign material and the primary defense system against infectious organism. Both theory are correct.