What is the basic principle of vaccination ? How do vaccines prevent microbial infections ? Name the organism from which hepatitis $B$ Vaccine is produced.

Name a recombinant vaccine that is currently being used in vaccination program.

The thymus is a lobed organ located near the $…A…$ and beneath the $…B… $ The most appropriate combination for $\mathrm{A}$ and $\mathrm{B}$ is

Which of the following is a pentameric immunoglobulin and is produced first in a primary response to an antigen?

Assertion : Interferons are a type of'antibodies produced by body cells infected by bacteria.

Reason : Interferons stimulate inflammation at the site of injury.