Question

Some bacteria produce multiple toxins that interfere with the host’s immune response. For example, one bacterial toxin is a protease that cleaves the proteins that form tight junctions between skin cells. The result is severe, widespread blistering (patches of skin sort of peel away from the body). (a) Explain how this toxin helps the pathogen. (b) What branch of the immune system can best defend against this toxin?

Answer 1

a) Proteases are bacterial toxins but actually are enzymes to hydrolyze peptide bonds within peptides and proteins. There are many proteases important in pathogen infection. E.g. Elastase B is an elastolytic protease playing significant role in Cystic Fibrosis (CF) infection.

Elastase can degrade human and bovine elastin which is protein responsible for developing a biopolymer in organs and tissues, it gives elastic properties. Elastin is also found around vascular tissue besides its disintegration is related with vasculitis during bacterial infection.

Protease like Elastase also degrade collagen - another important human biopolymer.

Protease degrades proteins from human wound fluids and human skin. It inhibits fibroblast growth.

Protease interact with proteins responsible for human immune defence system, they degrade immunoglobuline A and immunoglobuline G.

So reduces antibody formation and helps pathogen to infect.

b) There are two branches of immune system innate immune system and adaptive immune system. Innate immune system is not specifc, quick, maintain homestasis and activate adaptive while adaptive immune system is Slow, Specific and Memory based.

Out of these systems, innate immune system can best defend against this toxin.