What is the basic principle of vaccination ? How do vaccines prevent microbial infections ? Name the organism from which hepatitis $B$ Vaccine is produced.
Assertion : Interferons are a type of'antibodies produced by body cells infected by bacteria.
Reason : Interferons stimulate inflammation at the site of injury.
Discribe the Innate immunity.
Some people who have suffered from a disease may not be affected again during their life time; such immunity is called