ICMI 2015

F.36 The Immune Response Against Chlamydia Suis Genital Tract Infection Partially Protects Against Re-Infection

Friday, July 17, 2015
Grand Hall and Gallery, Ground Floor & 1st Floor (Maritim Hotel)
Daisy Vanrompay, DVM, PhD , Lab of Immunology and Animal Biotechnology, Ghent University, Ghent, Belgium
Evelien De Clercq , Ghent University, Ghent, Belgium
Bert Devriendt, PhD , University of Ghent, Merelbeke, Belgium
Yin Lizi , Sichuan Agricultural University, Ya’an, China
Koen Chiers , Ghent University, Ghent, Belgium
Wim Van den Broeck , Ghent University, Ghent, Belgium
Eric Cox, DVM, PhD , Lab of Immunology, Ghent University, Merelbeke, Belgium
Background: Chlamydia suis is widespread in commercial pig production and causes important economic losses. Currently, C. suis infections are mainly associated with conjunctivitis and reproductive disorders in sows and boars.

Objectives: The aim was to reveal the characteristics of genital C. suis infection and re-infection in female pigs by studying the immune response, pathology, replication of chlamydia in the genital tract and bacterial excretion.

Methods: Pigs were intravaginally infected and re-infected with the C. suis reference strain S45.

Results: S45 is pathogenic for the urogenital tract. Chlamydia replication occurred throughout the urogenital tract, causing inflammation and pathology. The infection elicited both cellular and humoral immune responses. Compared to the primo-infection of pigs with C. suis, re-infection was characterized by less severe macroscopic lesions and less chlamydial elementary bodies and inclusions in the urogenital tract. This indicates the development of a certain level of protection following the initial infection. Protective immunity against re-infection coincided with higher chlamydia-specific IgG and IgA antibody titers in sera and vaginal secretions, higher proliferative responses of peripheral blood mononuclear cells (PBMC), higher percentages of B lymphocytes, monocytes and CD8+ T cells and upregulated production of IFN-γ and IL-10 by PBMC. Data on immunohistochemistry will be presented.

Conclusions: Although C. suis is often still considered as an insignificant pathogen of pigs, it was demonstrated to be a primary pathogen of the urogenital tract. Furthermore, we established an experimental challenge model, suitable for further pathological and immunological investigations and will probably also be useful for studying vaccine development.