Bacteriophage

is the term referred to a virus that used bacteria as their host.

Bacteria creates two types of toxin which are:

1. Exotoxin

2. Edotoxin

Exotoxin

A component of toxin obtained from gram negative bacteria cells envelop, the cell envelope is made up of lipid and polysaccharide and the outside of the cell, the envelope is made up of protein which is called lipopolysaccharide combinations of lipid and polysaccharide.

Endotoxin

This substance are secreted by the certain viable bacteria and the substance is a potent poison which bacteria secreted into the host system .

A exotoxin is made up of two component fragment which are

fragment A, and fragment B.

Fragment A: is an exotoxin that exact a critical pathogenic action on their host.

Fragment: this fragment is a carrier receptor that bring to the host a receptor its pathway for fragment to enter the host cells.

Exotoxin can be converted to toxoid which can be used as an immunization.