Toll-like receptors

A. are used by cells to identify the presence of microbes

B. are pattern recognition receptors, bind specific parts that are unique to bacteria

C. when bound activate gene expression such as the production of cytokines

D. a and b

E. all of the above e

E. all of the above

Explanation:

Toll-like receptors are found on the surface of immune cells such as dendritic cells and are activated upon recognition of pathogens. They are so called pattern recognition receptors as they are able to recognize the pathogen-associated molecular patterns and trigger a series of reactions within the immune cells including cytokines, defensins and other bacteriocidal molecules.