Production of monoclonal antibodies for detection of Vibrio harveyi

Monoclonal antibodies (MAbs) against Vibrio harveyi were produced from mice immunized with heat-killed and SDS-mercaptoethanol-treated highly virulent V harveyi 639. Fifteen MAbs were selected and sorted into 6 groups according to their specificity to various proteins of apparent molecular weight ranging from 8 to 49 kDa. Some antibodies were used for detection of V harveyi at concentrations as low as 10(4) CFU ml(-1) using immunodot blots. Most of the selected MAbs did not show cross-reactivity to other Vibrio species and other Gram-negative bacteria tested. Only 1 MAb (VH39-4E) showed slight cross-reactivity to Aeromonas hydrophila. Another MAb (VH24-8H) bound lightly to V harveyi 1526 but strongly to V harveyi 639, allowing rapid differentiation. Two of the MAb groups were used to localize V harveyi in tissues of infected black tiger shrimp Penaeus monodon by immunohistochemistry. This study demonstrates the versatility of a highly specific immunological tool for the detection of V harveyi in aquaculture and opens the way for further development of convenient test kits.