| Summary: | 碩士 === 國立成功大學 === 生物科技研究所碩博士班 === 99 === High diversity and multiple serotypes in bacteria are the main bottleneck of cross-protective vaccine development. In previous studies, our lab isolated three protective immunogens, HSP60, enolase and GAPDH in Photobacterium damselae subsp. Piscicida (Ph. d. p.) by immunoproteomics
approach. In other studies, Vibrio campbellii was identified as a pathogen in fish farm in Tainan. These three immunogens were also isolated from this V. campbellii by the same approach. Preliminary data showed that the same immunogens derived from Ph. d. p. and V. campbellii shares at least 84 % nucleotide identity and 94 % amino acid homology. HSP60, enolase and GAPDH were considered as high conserved immunogens.
We evaluated the feasibility of using these three immunogens as universal vaccine candidates in this research. Orange-spotted grouper were immunized with E.coli expressing rHSP60, rEnolase and rGAPDH derived from Ph. d. p. and V. campbellii, and challenged with V. campbellii. Results indicated that rHSP60, rEnolase and rGAPDH of Ph. d. p. did not protect V. campbellii challenge, indicating antigens even contain 94 % amino acid similarity, still could not provide cross-protectivity.
Homology modeling prediction results indicated that the difference of amino acids sequences of these three pairs of proteins located on their surface. We suggested the variable surface structure may be the key in determining the response of immunity.
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