Exotoxin

Exotoxins

1. Heat - labile proteins secreted outside cell wall by certain species of gram +ve and garm -ve bacteria.

(Inactivated at high temperature)

2. It is antigenically strong, so it used for making toxoids.

3. Toxoids are non poisonous, non toxic substance produced by treatment of exotoxins with formaldehyde.

As result, their toxic proteins are destroyed but antigenic properties remains high to stimulate antibodies.

For example;

Tetanus toxoid

Diphtheria toxoid