Poly d,l-lactide-co-glycolic acid (PLGA)-encapsulated vaccine on immune system in Epinephelus bruneus against Uronema marinum

We investigate the efficacy of poly d,l-lactide-co-glycolic acid (PLGA)-encapsulated vaccine on innate and adaptive immune response in kelp grouper (Epinephelus bruneus) against Uronema marinum at weeks 1, 2, and 4. The respiratory burst (RB) activity, complement activity, and α2-macroglobulin were significantly enhanced in fish immunization with vaccine on week 4 whereas vaccine and PLGA-encapsulated vaccine from weeks 1 to 4. The serum lysozyme activity, antiprotease activity, and antibody level were significantly enhanced in fish immunized with vaccine and PLGA-encapsulated vaccine on weeks 2 and 4. The cumulative mortality was low in PLGA-encapsulated vaccine with 20% whereas high in PLGA and vaccine with 40% and 30%. The results from the present study suggest that PLGA-encapsulated vaccine is useful for further design of immunoprophylatic nano formulation against scuticociliatosis.

Serum lysozyme activity of blood leukocytes of E. bruneus (n = 6) control (C), infected (I), injected with PLGA, vaccine (V), and PLGA-encapsulated vaccine (PLGA + V) against U. marinum.Highlights► RB, complement, and α2-macroglobulin levels were enhanced from weeks 1 to 4. ► Lysozyme activity, antiprotease, and antibody level enhanced on weeks 2 and 4. ► Mortality was 20% in PLGA − V whereas 40% and 30% in PLGA and V. ► This results suggest that PLGA − V useful for nano formulation against scuticociliatosis.