Pluronic P85 enhances the efficacy of outer membrane vesicles as a subunit vaccine againstBrucella melitensischallenge in mice

Abstract

Brucellosis is the most common zoonotic disease worldwide and there is no vaccine for human use. Brucella melitensis Rev1, a live attenuated strain, is the commercial vaccine for small ruminants to prevent B. melitensis infections but has been associated with abortions in animals. Moreover, strain Rev1 is known to cause disease in humans and cannot be used for human vaccination. Outer membrane vesicles (OMVs) obtained from B. melitensis have been shown to provide protection similar to strain Rev1 in mice against B. melitensis challenge. In the present work we tested the efficacy of Pluronic P85 as an adjuvant to enhance the efficacy of Brucella OMVs as a vaccine. P85 enhanced the in vitro secretion of TNF-α by macrophages induced with OMVs and P85. Further, P85 enhanced the protection provided by OMVs against B. melitensis challenge. This enhanced protection was associated with higher total IgG antibody production but not increased IFN-γ or IL-4 cytokine levels. Moreover, P85 alone provided significantly better clearance of B. melitensis compared to saline vaccinated mice. Further studies are warranted to find the mechanism of action of P85 that provides non-specific protection and enhances the efficacy of OMVs as a vaccine against B. melitensis.

PEG modified liposomes containing CRX-601 adjuvant in combination with methylglycol chitosan enhance the murine sublingual immune response to influenza vaccination

“…HI titers were higher for each of the 25% Pluronic modified liposome groups containing CRX-601 adjuvant compared to respective vehicle controls. However, these differences were not statistically significant ( P > 0.05 ) and the high titers observed in the absence of CRX-601 could be due to the previously reported adjuvant effect of Pluronics [33, 34]. IgG responses largely correlated with HI titers, except for CRX-601 adjuvanted 25% L64 and 25% F68 liposome groups where IgG concentrations were significantly higher compared to the respective vehicle controls (Figure S5).…”

Recent advances in Brucella abortus vaccines

“…B. abortus OMVs are mainly composed for outer membrane proteins (Omps) and have been associated with modulation of host immune response by inhibition of TNF-α and IL-8 response, inhibition of IFN-γ induced expression of MHC class II molecules on human monocytes and increase in expression of adhesion molecules [ 97 – 99 ]. A Brucella melitensis vaccine based on OMVs has been tested and showed promising results in BALB/c mice [ 100 ]. Furthermore, it is already available a vaccine based on OMVs, against meningococcus serogroup B ( Neisseria meningitides ) in some countries as Cuba, Norway and New Zealand [ 97 ].…”

Epidemiological features and risk factors associated with the spatial and temporal distribution of human brucellosis in China

“…B. melitensis , B. abortus, B. suis and B. canis often cause abortion and infertility in these natural hosts [ 4 , 8 - 11 ]. B. melitensis Rev.1 is an effective commercial vaccine which is currently used for small ruminants, and no satisfactory vaccine against human infection is available [ 12 , 13 ]. Brucellosis has a worldwide distribution in both humans and animals with the exception of several industrialized countries, causing tremendous health and economic burden [ 14 ].…”