Mucosal immune response of spotted sand bass Paralabrax maculatofasciatus (Steindachner, 1868) orally immunised with an extracellular lectin of Aeromonas veronii

To assess the immunogenic and immunoprotective role of the extracellular le ctin from Aeromonas veronii (MCBP), which has affinity for mucosal constitu ents such as mucin, lactoferrin, immunoglobulins and collagen, spotted sand bass (Paralabrax maculatofasciatus) were orally immunised either with solu ble MCBP, adjuvant-conjugated MCBP or immobilised MCBP on latex microsphere s. The results suggest that the MCBP is capable of eliciting protective imm unity against A. veronii infections when administered orally. The highest m ucosal immune response was elicited in fish immunised with MCBP covalently linked to cholera toxin B subunit (CTB) or to Escherichia coli heat-labile toxin (hLT). MCBP-CTB was found to elicit immunoprotection against a challe nge with live Aeromonas cells with a relative percent survival of almost 70 % and without the expression of the severe histopathological alterations in duced by A. veronii. (C) 2001 Academic Press.