Gm. Forward et Ptk. Woo, AN IN-VITRO STUDY ON THE MECHANISM OF INNATE IMMUNITY IN CRYPTOBIA-RESISTANT BROOK CHARR (SALVELINUS-FONTINALIS) AGAINST CRYPTOBIA-SALMOSITICA, Parasitology research, 82(3), 1996, pp. 238-241
Fresh plasma from Cryptobia-resistant brook charr (Salvelinus fontinal
is) lysed Cryptobia salmositica under in vitro conditions. However, th
e parasite was not lysed if the plasma was heat-inactivated at 37 degr
ees C for 2 h or after the addition of ethylenediaminetetraacetic acid
(EDTA) to chelate the free Mg2+ ions. Addition of Mg2+ ions to EDTA-c
helated plasma restored parasite lysis. Treatment of Cryptobia-resista
nt plasma with either ethylenebis(oxyethylenenitrilo)tetraacetic acid,
a Ca2+-chelating agent, or cobra venom factor did not reduce their ly
tic titres. The alternative pathway of complement activation is the me
chanism of innate immunity against C. salmositica. The present study a
lso shows that there is functional heterogeneity amongst the complemen
t components activated via the alternative pathway within a species (b
rook charr) and between species (brook charr and goldfish) of fishes.