Oral Passive Immunization of Carp Cyprinus carpio with Anti-CyHV-3 Chicken Egg Yolk Immunoglobulin (IgY)

抄録

Cyprinid herpesvirus 3 (CyHV-3), also called as koi herpesvirus, has spread all over the world since its emergence in the late 1990s. CyHV-3 causes a fatal disease, which leads to a mortality rate of more than 80% in common and ornamental (koi) carp Cyprinus carpio. The novel anti-CyHV-3 strategies are urgently needed. In this report, CyHV-3 particles were concentrated and then used for the immunization of hens in order to obtain the anti-CyHV-3 egg yolk immunoglobulin (IgY). The proportion of anti-CyHV-3 IgY to total IgY in water-soluble fraction of egg york increased from 0.014% to 23.9% after three times of immunization. The anti-CyHV-3 effects of IgY were then examined by in vivo and in vitro assays. The results suggested that the anti-CyHV-3 serum of hens and the purified anti-CyHV-3 IgY from eggs could prevent common carp brain (CCB) cells from infection. After oral passive immunization with IgY, the mortality of carp significantly decreased from 85% to 50% (P < 0.05) when the fish were challenged with CyHV-3 at a dose of 40 TCID₅₀/fish. These results will possibly pave the way for the prevention of CyHV-3 infection.