Heat-labile enterotoxin (LT)

Definition

Heat-labile enterotoxin (LT) is a toxin produced by certain strains of Escherichia coli. It is sensitive to heat and can cause severe diarrhea by increasing cAMP levels in host cells.

5 Must Know Facts For Your Next Test

1. Heat-labile enterotoxin has an A-B subunit structure where the A subunit has enzymatic activity and the B subunit binds to host cell receptors.
2. The toxin activates adenylate cyclase, leading to elevated cyclic AMP (cAMP) levels that result in water and electrolyte loss from cells.
3. LT is similar in mechanism to cholera toxin, both causing watery diarrhea through similar biochemical pathways.
4. It is heat-sensitive, meaning it loses its activity when exposed to high temperatures for a prolonged period.
5. Detection of LT in clinical samples often involves immunoassays or PCR methods targeting the genes encoding the toxin.

Review Questions

Related terms

Cholera Toxin:

A toxin produced by Vibrio cholerae that also increases cAMP levels leading to severe diarrhea.

Adenylate Cyclase:

An enzyme activated by LT that converts ATP to cyclic AMP (cAMP).

Immunoassay: A laboratory method used for detecting or quantifying specific proteins or toxins based on antigen-antibody interactions.