Oral Presentation International Veterinary Immunology Symposium 2016

Pig as a model to understand the cellular immune response to Chlamydia trachomatis and suis infections (#8)

Tobias Kaeser 1 , Alex Pasternak 1 , Meghanne Rieder 1 , Glenn Hamonic 1 , Ken Lai 1 , Mario Delgado-Ortega 1 , Heather L Wilson 1 , Jo-Anne Dillon 1 , Volker Gerdts 1 , Fran├žois JMA Meurens 2
  1. VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
  2. UMR 1300 BioEpAR INRA Oniris, Nantes Atlantic National College of Veterinary Medicine, Nantes, Pays de la Loire, France

Chlamydia trachomatis (CT) infections cause serious diseases including infertility and trachoma. A vaccine against CT is not available but urgently needed. A recent study shows that pigs could serve as an affordable and relevant pre-clinical animal model but the porcine cellular immune response to the disease is poorly understood. Therefore, our aim was to establish a comprehensive analysis of porcine chlamydia-specific T-cell subsets. Pigs were synchronized and infected in standing estrus with 10^8 IFUs C. suis (CS) or CT intra-vaginally and intra-uterine. Then they were clinically monitored, and serum, swabs and blood were taken to analyse the humoral immune response, detect chlamydia, analyse immune cell counts and for PBMC isolation. Chlamydia-specific CD4+ T cells, CTLs, and gamma-delta-T cells were detected after in vitro restimulation of CFSE-labelled PBMC via flow cytometry while cytokine production was analysed via multiplex. Clinical scores, qPCR and serology confirm CS and CT infection with gross pathological changes in 3/4 CS-infected and 2/4 CT-infected animals. Proliferation analyses showed a chlamydia-specific CD4+ T-cell response while CTLs and gamma-delta-T cells responded less effectively. Multiplex analyses revealed IFNg and IL17 indicating a strong TH1 and TH17 responses. We incorporated recent advances regarding porcine toolbox to analyse the chlamydia-specific cellular immune response demonstrating the important role of a TH1 response upon in vivo CT infection of pigs. With the ability to comprehensively analyse not only the humoral but also the cellular responses, pigs can now serve as a relevant animal-model in chlamydia vaccine development bridging the gap between mice and primates.