Zymosan A (Sigma, St Louis, USA) was boiled and washed three times with Hank’s Balanced Salt
solution (HBSS). A stock solution of 10 mg ml1 was made in the same buffer and stored at 70 (C until
required. Washed zymosan was opsonised with 25% rainbow trout sera diluted in HBSS, incubated for 25
min at room temperature and washed three times with HBSS. A 10 mM stock solution of luminol
(5-amino-2,3-dihydro-1,4-pthalazinedione, Sigma) was prepared in 0.2 M sodium borate buffer, pH 9.0,
and stored at 70 (C until use.