Immune response to Rhodococcus equi ATCC 33701-secreted proteins in mice and identification of immunogenic recombinant proteins by dot-blotting

Corinne Barbey (1, 2) , Séverine Cauchard (2) , Julien Cauchard (2) , Claire Laugier (2) , Axel Hartke (3) , Sandrine Petry (2)

1 LMSM - Laboratoire de Microbiologie Signaux et Microenvironnement
2 Laboratoire de pathologie équine de Dozulé
3 LME - Laboratoire de Microbiologie de l’Environnement

Rhodococcus equi remains a significant pathogen, causing severe pneumonia in foals. The development of vaccines and serologic diagnosis could be greatly facilitated by studying the humoral immune response to this equine pathogen. In this study, a crude extract of R. equi ATCC 33701-secreted proteins combined with the Montanide® ISA70 adjuvant was found to be highly immunogenic in mice with the highest titer of 99,000 on day 42 after the first subcutaneous immunization. This immune response was dependent on the quantity of proteins injected and the presence of adjuvant. By dot-blotting, eight recombinant secreted proteins were identified to react strongly with sera from immunized mice. Of these eight proteins, four were detected as immunogenic only when administered in conjunction with adjuvant. This screening strategy led to the identification of promising new candidates for vaccine development.

Keywords: <i>Rhodococcus equi</i>; Secreted proteins; Immunization of mice; Vaccine antigens; Antigen screening; Dot-blotting

Domains: Life Sciences [q-bio]; Life Sciences [q-bio]; Biochemistry, Molecular Biology

Corinne Barbey, Séverine Cauchard, Julien Cauchard, Claire Laugier, Axel Hartke, et al.. Immune response to Rhodococcus equi ATCC 33701-secreted proteins in mice and identification of immunogenic recombinant proteins by dot-blotting. Research in Veterinary Science, 2012, 93 (1), pp.172-176. ⟨10.1016/j.rvsc.2011.05.003⟩. ⟨hal-02180933⟩