Production of putative virulence factors by Renibacterium salmoninarum grown in cell culture.
A cell culture system, employing the fish cell line Epithelioma papillosum cyprini (EPC), was developed to study the synthesis of intracellular antigen and the expression of putative virulence factors by Renibacterium salmoninarum. EPC cultures infected with R. salmoninarum could be maintained for 7 weeks, during which the pathogen multiplied intracellularly. Immunohistochemical examination of infected cultures revealed the production of the p57 antigen, haemolysin and cytolysin. The intracellular nature of the infection was confirmed by transmission electron microscopic examination of EPC monolayers. A comparison of the relative virulence of bacterial cells cultured in EPC cells and on agar plates revealed that the former were markedly more virulent in challenge experiments with juvenile rainbow trout (Oncorhynchus mykiss Walbaum). The EPC cell culture model provided a system for the study of R. salmoninarum under more natural conditions than those achieved with plate culture techniques.
Mcintosh
D
D
Department of Biological Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
Flaño
E
E
Departamento de Biología Celular y Anatomía, Facultad de Biología, Universidad de León, 24071-León, Spain.
Grayson
T H
TH
Department of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK.
Gilpin
M L
ML
Department of Biological Sciences, University of Plymouth, Plymouth PL4 8AA, UK.
Austin
B
B
Department of Biological Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
Villena
A J
AJ
Departamento de Biología Celular y Anatomía, Facultad de Biología, Universidad de León, 24071-León, Spain.
D000818:Animals; D000942:Antigens, Bacterial / Q000096:biosynthesis; D001431:Bacteriological Techniques; D002460:Cell Line; D003603:Cytotoxins / Q000096:biosynthesis; D005399:Fishes; D006094:Gram-Positive Bacteria / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology; D006460:Hemolysin Proteins / Q000096:biosynthesis; D008854:Microscopy, Electron; D014774:Virulence
D000942:Antigens, Bacterial; D003603:Cytotoxins; D006460:Hemolysin Proteins