We previously described that
immunopotentiators, CVCVA5, increased the efficacy of H5 and H9 subtype
avian influenza vaccines in chickens, ducks, and geese. In this study, we further investigated the effects of the CVCVA5 for improving the efficacy of other univalent or multivalent
inactivated vaccines. The immune response administrated with half-dose of monovalent
vaccine plus CVCVA5 were higher than those of one dose of monovalent
vaccine without
immunopotentiators as measured by levels of
antibodies from serum, tears and bronchoalveolar lavage fluids, and
cytokines of IFNγ and
IL-4 from serum.
Vaccines included the univalent
vaccine of Newcastle Disease virus (ND), Egg Drop Syndrome virus (EDS), Infectious Bronchitis virus (IB), and Infectious Bursal Disease virus (IBD). The CVCVA5 also improved the immune response of both ND and IBD
vaccines with less dosage. The sterile protective immunity was monitored with one- or a half-dose of adjuvanted ND
vaccine or one dose of adjuvanted IBD
vaccine, respectively. The improved immune efficacy was observed in a half-dose of adjuvanted
bivalent vaccines compared to one dose of
vaccines without CVCVA5 as measured by the antibody levels, including
bivalent vaccine of ND-H9, ND-IB, and ND-IBD. The CVCVA5 also boosted the immune efficacy of the
tetravalent vaccine (ND-IB-EDS-H9). A half-dose of adjuvanted commercial
vaccine or 75%
antigen-sparing adjuvanted
vaccine elicited similar antibody levels to those of one dose non-adjuvanted commercial
vaccines. The CVCVA5 improved the effect of a booster vaccination as measured by the antibody levels against H5 or H9 virus
antigens, in which chickens primed with the adjuvanted ND-IB
vaccines given a booster with H5-H9
bivalent vaccines without CVCVA5 using 5-day intervals. The inflammatory response may contribute to these additional effects by increasing the levels of IFNγ and
IL-4 after the injection of the adjuvanted ND-IB
vaccines. Results indicated that the CVCVA5 improved the serum and mucosal antibody levels,
cytokine levels of the chickens given the univalent
vaccine, and also improved serum antibody titers in bivalent and
tetravalent vaccines. This has a potential as an improve
vaccine.