Jo. Sunyer et L. Tort, NATURAL HEMOLYTIC AND BACTERICIDAL ACTIVITIES OF SEA BREAM SPARUS-AURATA SERUM ARE EFFECTED BY THE ALTERNATIVE COMPLEMENT PATHWAY, Veterinary immunology and immunopathology, 45(3-4), 1995, pp. 333-345
Sea bream serum displayed bactericidal and hemolytic activities. These
activities were depleted when serum was incubated with different acti
vators of the alternative complement pathway (ACP). Ethylenediaminetet
raacetic acid (EDTA) inhibited both the hemolytic and bactericidal act
ivities, while ethyleneglycol-bis (B-aminoethyl ether)-N,N,N'-tetraace
tic acid (EGTA) was not inhibitory. An antibody against the putative t
hird component of sea bream component (C3) was produced. It was observ
ed by immunoelectrophoresis that the sea bream C3 and human C3 migrate
d in the same position. Crossed immunoelectrophoresis showed that sea
bream C3 exhibited a similar pattern of activation when compared with
its human counterpart. The anti-sea bream C3 antibody inhibited both b
actericidal and hemolytic activities. It was concluded that both serum
actions were displayed by the ACP. The best conditions for the sea br
eam ACP titration were investigated. Of all mammal erythrocytes tested
, rabbit erythrocytes (RaRBC) were found to be the best ACP activators
and thus were used for the titration. Sea bream showed very high ACP
titers when compared with those of mammals. Absorption of naturally oc
curring antibodies against rabbit RaRBC did not influence the ACP tite
rs. Enzymatic removal of sialic acid from different mammalian erythroc
ytes increased the sensitivity of these cells to hemolysis mediated by
the sea bream ACP.