Fifty ml of chicken bile was initially dialyzed against aqainst butter followal by buffered saline, and chxoxnatgrap]M on DEAF dialuzed column. The majtdty of bi]ioary IgA was eluel with O,3M NaQ and further dialyd against PBS. The crxie bihary IgA was peclpitaed wtih rabbit anti-chicken IgA anten, The waterinsolubIe lattice nipitate was washer! with PBS. Rabbit anti-chicken IgA (H-i-L) anti-semrn was gcdwei by the infrttion of rabbit with the washed lattice aipitue emulsifier! withadjuvanis. The antiserum was aborlerlwithSepharoseCL-4B conjugaelby pure 1gM to obtain anti-IgA (H): antiserum.