Poly d,l-lactide-co-glycolic acid-liposome encapsulated ODN on innate immunity in Epinephelus bruneus against Vibrio alginolyticus

The efficacy of poly d,l-lactide-co-glycolic acid (PLGA)–liposome (L) encapsulated oligodeoxynucleotides with unmethylated deoxycytidyl-deoxyguanosine motifs (CpG-ODNs) on innate and adaptive immune response and disease resistance in kelp grouper (Epinephelus bruneus) against Vibrio alginolyticus at weeks 1, 2, and 4 is reported. The superoxide dismutase (SOD), respiratory burst, and lysozyme activities significantly increased in E. bruneus when immunized with ODN, PLGA + ODN, L + ODN, and PLGA + L + ODN on weeks 2 and 4. The serum complement activity was significantly enhanced with L + ODN and PLGA + L + ODN on week 1 while it increased with PLGA + ODN, L + ODN, and PLGA + L + ODN on weeks 2 and 4. The antibody titre consistently was increased with PLGA or L encapsulated with ODN (PLGA + ODN, L + ODN, and PLGA + L + ODN) from weeks 1 to 4. The cumulative mortality was 20% each in PLGA + ODN administered groups and 15% each in ODN, L + ODN, and PLGA + L + ODN groups during a period of 30 days. The present study suggests that PLGA–liposome encapsulated ODN has the potential to modulate the immune system and can serve as a useful tool for further design of immunoprophylatic nano drug formulations against bacterial diseases.