Mucosal co-immunization of mice with recombinant lactococci secreting VapA antigen and leptin elicits a protective immune response against Rhodococcus equi infection.

Abstract:

:Rhodococcus equi causes severe pneumonia in foals and has recently gained attention as a significant opportunistic pathogen in immunocompromised humans. However, no effective vaccine to prevent rhodococcosis is currently available. In this study, we have engineered the food-grade bacterium Lactococcus lactis to secrete the virulence-associated protein A from R. equi (LL-VapA). The immunogenic potential of LL-VapA strain was then evaluated after either intragastric or intranasal immunization in mice either alone or in combination with LL-Lep, a recombinant strain of L. lactis secreting biologically active leptin, a pleiotropic hormone with significant immunomodulatory properties. Intragastric administration of LL-VapA led to the highest VapA-specific mucosal response whereas intranasal administration led to the highest systemic immune responses. Cytokines released from in vitro-stimulated spleen cells show both a strong IFN-γ response and an increase of IL-4 level in all immunized groups, except for the group intranasally co-administered with both LL-VapA and LL-Lep. Strikingly, a significant reduction in R. equi viable counts in liver and spleen was observed four days after intravenous challenge with a virulent strain of R. equi in all immunized groups except for the group vaccinated by intragastric route with LL-VapA. Altogether, our results demonstrate that LL-VapA can evoke a T(H)1-based protective immune response in intranasally immunized mice. This response is enhanced when co-administered with LL-Lep strain, whereas only co-administration of LL-VapA and LL-Lep can induce a protective immune response in intragastric vaccinated mice, associated with a T(H)1/T(H)2 cytokine response.

journal_name

Vaccine

journal_title

Vaccine

authors

Cauchard S,Bermúdez-Humarán LG,Blugeon S,Laugier C,Langella P,Cauchard J

doi

10.1016/j.vaccine.2011.10.026

subject

Has Abstract

pub_date

2011-12-09 00:00:00

pages

95-102

issue

1

eissn

0264-410X

issn

1873-2518

pii

S0264-410X(11)01633-1

journal_volume

30

pub_type

杂志文章

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