Which statement correctly describes Toll-like receptors?

Which statement correctly describes Toll-like receptors?

• A. Toll-like receptors use pattern recognition in host cell membranes to trigger innate responses.
• B. They secrete antibodies.
• C. They present antigens to T cells.
• D. They differentiate into NK cells.

Answer: (A)

Toll-like receptors are pattern recognition receptors located on host cell membranes (and in endosomes) that detect conserved microbial components. When they bind pathogen-associated molecular patterns, they trigger signaling pathways that activate innate immune responses, leading to cytokine production and upregulation of costimulatory molecules to help shape the adaptive response. This is exactly what the statement describes: using pattern recognition in host cell membranes to trigger innate responses. They do not secrete antibodies—that role belongs to B cells. They do not present antigens to T cells—that task is performed by MHC-peptide complexes on antigen-presenting cells. They also do not differentiate into NK cells.

Toll-like receptors are pattern recognition receptors located on host cell membranes (and in endosomes) that detect conserved microbial components. When they bind pathogen-associated molecular patterns, they trigger signaling pathways that activate innate immune responses, leading to cytokine production and upregulation of costimulatory molecules to help shape the adaptive response. This is exactly what the statement describes: using pattern recognition in host cell membranes to trigger innate responses. They do not secrete antibodies—that role belongs to B cells. They do not present antigens to T cells—that task is performed by MHC-peptide complexes on antigen-presenting cells. They also do not differentiate into NK cells.