Answer:

antiserum

Answer	Crossword Clue
ANTISERUM	Immunity provider
ANTISERUM	Snakebite treatment
ANTISERUM	It provides immunity

ANTISERUM	Term in immunology.
ANTISERUM	Herpetologist's supply
ANTISERUM	Pathogen combatant

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.