Assessment of the acid phosphatase CP01850 from Corynebacterium pseudotuberculosis in DNA and subunit vaccine formulations against caseous lymphadenitis

A.F.S Rezende,A.A Brum,H.S Thurow,R.W Portela,F.K Seixas,G.L Sá,D.C Braite,V.A.C Azevedo,F.S.B Bezerra,S Borsuk

doi:10.1590/1678-4162-10790

Abstract

ABSTRACT The target cp1002_RS01850 from Corynebacterium pseudotuberculosis was used to construct a DNA and recombinant subunit vaccine against caseous lymphadenitis. Recombinant protein rCP01850 was expressed in Escherichia coli using pAE vector, and DNA vaccine was engineered with pTARGET vector. BALB/c mice were divided in five groups containing eight animals each, inoculated with: pTARGET/cp01850 as DNA vaccine (G1); rCP01850 plus Al (OH)3 as recombinant subunit vaccine (G2); pTARGET/cp01850 and a boost with rCP01850 plus Al (OH)3 (G3); pTARGET (G4); or Al (OH)3 (G5). Mice were inoculated and blood samples were collected on days 0, 21, and 42 for the analysis of total IgG, IgG1 and IgG2a by ELISA. In each group, five animals were challenged with Mic-6 C. pseudotuberculosis strain, and three were used for cytokine quantification by qPCR. Although no group has been protected by vaccines against lethal challenge, G2 showed an increase in the survival rate after challenge. Significantly higher levels of IL-4, IL-12, IFN-γ, total IgG, IgG1 and IgG2a were also detected for G2, evidencing a mixed Th1/Th2 immunological profile. In conclusion, despite no protection level provided by different vaccinal strategies using cp1002_RS01850 from C. pseudotuberculosis, G2 developed a Th1/Th2 immune response with an increase in survival rate.

Highlights

Caseous lymphadenitis (CLA) is a chronic, infectious disease caused by Corynebacterium pseudotuberculosis mainly affecting small ruminants
The DNA vaccine pTARGET/cp09720 induced a significant increase in IFN-γ levels, indicating a Th1 response, the phenotype related to CLA protection (Brum et al, 2017)
Recombinant subunit vaccines have been tested for CLA immune prophylaxis, since they are considered safe for inducing lower levels of side effects, resulting in variable protection rates depending on the C. pseudotuberculosis antigen selected (Hodgson et al, 1999; Pinho et al, 2009; Silva et al, 2014; Droppa-Almeida et al 2016; Brum et al 2017; Silva et al, 2018)

Summary

Introduction

Caseous lymphadenitis (CLA) is a chronic, infectious disease caused by Corynebacterium pseudotuberculosis mainly affecting small ruminants. Antibiotic therapy becomes difficult because the drugs cannot reach C. pseudotuberculosis in encapsulated lesions (Pépin and Paton, 2011). The DNA vaccine pTARGET/cp09720 induced a significant increase in IFN-γ levels, indicating a Th1 response, the phenotype related to CLA protection (Brum et al, 2017). Recombinant subunit vaccines have been tested for CLA immune prophylaxis, since they are considered safe for inducing lower levels of side effects, resulting in variable protection rates depending on the C. pseudotuberculosis antigen selected (Hodgson et al, 1999; Pinho et al, 2009; Silva et al, 2014; Droppa-Almeida et al 2016; Brum et al 2017; Silva et al, 2018)

Methods

Results

Discussion

Conclusion