Which antimicrobial peptide secreted by sweat glands disrupts membranes and ion channels to inhibit bacteria and fungi?

• A. Histatins
• B. Bacteriocins
• C. Cathelicidin
• D. Dermcidin

Answer: (D)

Sweat glands secrete an antimicrobial peptide that disrupts microbial membranes and ion channels, crippling the cells by collapsing ion gradients and causing leakage. Dermcidin is the peptide this describes because it is produced by eccrine sweat glands and acts by aggregating to form channels in the membranes of bacteria and fungi, leading to their inhibition or death in the salty, sweat-rich environment. This broad-spectrum activity and its direct origin from sweat glands distinguish dermcidin from the others: histatins are primarily salivary antifungals, bacteriocins are produced by bacteria, and cathelicidin (LL-37) is made by various human tissues but not specifically by sweat glands.