A Cell Compound That Attacks Allergens

This page is the CodyCross answer for the clue below from Spa Time, Group 814, Puzzle 3 (Antioxidants).

Question is: A Cell Compound That Attacks Allergens

and the answer is: HISTAMINE

Word Meaning:

HISTAMINE — (biochemistry) An amine, C₅H₉N₃, formed by decarboxylation of histidine, that causes dilatation of capillaries, contraction of smooth muscle, and stimulation of gastric acid secretion; it is released during allergic reactions.

Definitions from Wiktionary.