Ooyama Tsuyoshi, Hirokawa Yusuke, Minami Takayuki, Yasuda Hiroshi, Nakai Toshihiro, Endo Makoto, Ruangpan Lila, Yoshida Terutoyo
Miyazaki Prefectural Fisheries Experimental Station, Miyazaki Prefecture, Aoshima, Miyazaki 6-16-3, Japan.
Dis Aquat Organ. 2002 Oct 4;51(3):169-77. doi: 10.3354/dao051169.
The cell-surface properties of strains of Lactococcus garvieae were examined. Two capsular types were found, one with a highly developed capsule (KG9408) and one with a micro-capsule (MS93003) carrying fimbriae-like components projecting from the cell surface. One strain (NSS9310) had neither cell capsular nor fimbriae-like structures on its cell surface. The strains with the highly developed capsule were more virulent to fish than either the micro-capsular or non-capsular strains. The KG9408, MS93003 and NSS9310 strains could be clearly differentiated by their susceptibility to bacteriophages. Protection against L. garvieae infection was induced in the yellowtail Seriola quinqueradiata by immunization with formalin-killed L. garvieae KG9408 and MS93003 cells. Although protection was also induced by immunization with NSS9310, the level of protection was significantly lower than that with KG9408 and MS93003 vaccines. Passive immunization with yellowtail immune sera raised against KG9408 and MS93003 conferred strong protection on yellowtail with rapid bacterial clearance after challenge with L. garvieae. Immunoblotting analysis of protein antigens extracted from L. garvieae strains using rabbit anti-KG9408 and anti-MS93003 sera and yellowtail anti-KG9408 and anti-MS93003 sera indicated that some bands in KG9408 and MS93003 strains were not detectable in NSS9310.
对加氏乳球菌菌株的细胞表面特性进行了检测。发现了两种荚膜类型，一种具有高度发达的荚膜（KG9408），另一种具有微荚膜（MS93003），其带有从细胞表面突出的菌毛样成分。一株菌（NSS9310）在其细胞表面既没有细胞荚膜也没有菌毛样结构。具有高度发达荚膜的菌株对鱼类的毒性比微荚膜菌株或无荚膜菌株更强。KG9408、MS93003和NSS9310菌株可通过它们对噬菌体的敏感性明显区分开来。用福尔马林灭活的加氏乳球菌KG9408和MS93003细胞对黄尾鰤进行免疫接种，可诱导其对加氏乳球菌感染产生保护作用。虽然用NSS9310进行免疫接种也能诱导产生保护作用，但保护水平明显低于用KG9408和MS93003疫苗的情况。用针对KG9408和MS93003产生的黄尾鰤免疫血清进行被动免疫，可在黄尾鰤受到加氏乳球菌攻击后迅速清除细菌，从而对其提供强大的保护。使用兔抗KG9408和抗MS93003血清以及黄尾鰤抗KG9408和抗MS93003血清对从加氏乳球菌菌株中提取的蛋白质抗原进行免疫印迹分析表明，NSS9310中检测不到KG9408和MS93003菌株中的一些条带。
