Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Streptococcus iniae CAMP Factor Lost its Co-hemolysis to Fish Red Blood Cells

Mengwei Xiao1, Kaiyu Wang1,2, Defang Chen3, Jun Wang1, Lanmin Li1, Xingxing Liu1, Yi Geng1,2, Xiaoli Huang3 and Dan Xiao4,

1Department of Basic Veterinary, Veterinary Medicine College, Sichuan Agricultural University, Ya?an 625014, Sichuan, P.R. China. 2Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Ya?an 625014, Sichuan, P.R. China. 3Department of Aquaculture, College of Animal Sicence& Technology, Sichuan Agricultural University, Ya?an, Sichuan 625014, P.R. China. 4Animal Health Research Institute of Tongwei Co., Ltd., Chengdu, Sichuan 610041, PR China.

Received on 06 July 2014 and accepted on 04 September 2014



Specific primers were used to amplify the gene cfi encoding CAMP factor of Streptococcus iniae(S. iniae) DGX07. CAMP factor ofnatural form of S. iniaecould be detected by Western-blot with anti-recombinant CAMP factor antiserum. Western-blot suggested that the amount of CAMP factor expressed inS. iniaewere very low and that might be not virulent enough to trigger immune response in rabbits. Western-blot also demonstrated its non-specific binding ability torabbit immunoglobulin G.CAMP factor showed binding and invasion ability toEpitheliomapapulosumcyprini cellsin vitro.However, hemolysis showed the recombinant CAMP factor could exhibit the classic co-hemolytic activity on some mammals?red blood cells but failed to cytolyse fish red blood cells, suggesting that CAMP factor lost its co-hemolysis to fish in S.iniae.

Keywords : cfi gene; molecular analysis; co-hemolysis; cell adherence and invasion; IgG binding.