The immune response against Chlamydia suis genital tract infection partially protects against re-infection

Abstract

The aim of the present study was to reveal the characteristic features of genital Chlamydia suis infection and re-infection in female pigs by studying the immune response, pathological changes, replication of chlamydial bacteria in the genital tract and excretion of viable bacteria. Pigs were intravaginally infected and re-infected with C. suis strain S45, the type strain of this species. We demonstrated that S45 is pathogenic for the female urogenital tract. Chlamydia replication occurred throughout the urogenital tract, causing inflammation and pathology. Furthermore, genital 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 blood B lymphocytes, monocytes and CD8⁺ T cells and upregulated production of IFN-γ and IL-10 by PBMC.

Development of aChlamydia suis-specific antibody enzyme-linked immunosorbent assay based on the use of a B-cell epitope of the polymorphic membrane protein C

“…The enteric pathogenicity of the reference strain was demonstrated in gnotobiotic piglets (Guscetti, Schiller, Sydler, Heinen, & Pospischil, ). In addition, C. suis S45 was also capable of causing an ascending urogenital infection following an experimental vaginal inoculation in gilts (De Clercq et al., ). Nowadays, C. suis is often found in rectal swabs of sows and gilts (De Puysseleyr, De Puysseleyr, Braeckman, et al, 2017), suggesting that autoinoculation from the rectum to the genitals might occur in pigs.…”

“…Group 1 consisted of positive control sera ( n = 40) that were weekly collected during 8 weeks from five Chlamydia ‐free conventional bred sows (Belgian Landrace) that were experimentally (vaginally) infected at the age of 9 weeks with the C. suis reference strain S45 (De Clercq et al., ). Group 2 consisted of positive control sera ( n = 35) that were weekly collected during 3 weeks from five Chlamydia ‐free conventional bred sows (Belgian Landrace) that were experimentally (vaginally) infected at the age of 17 weeks with C. suis strain S45 (De Clercq et al., ). Sera of groups 1 ( n = 40) and 2 ( n = 35) were known to be positive in an ELISA using purified C. suis S45 EBs as antigen (De Clercq et al., ).…”

“…Group 2 consisted of positive control sera ( n = 35) that were weekly collected during 3 weeks from five Chlamydia ‐free conventional bred sows (Belgian Landrace) that were experimentally (vaginally) infected at the age of 17 weeks with C. suis strain S45 (De Clercq et al., ). Sera of groups 1 ( n = 40) and 2 ( n = 35) were known to be positive in an ELISA using purified C. suis S45 EBs as antigen (De Clercq et al., ). Group 3 consisted of 55 negative control sera that were weekly collected during 11 weeks (from the age of 9–20 weeks) from five Chlamydia ‐free conventional bred sows (Belgian Landrace) that served as negative controls during an experimental infection experiment with C. suis strain S45 (De Clercq et al., ).…”

“…Sera of groups 1 ( n = 40) and 2 ( n = 35) were known to be positive in an ELISA using purified C. suis S45 EBs as antigen (De Clercq et al., ). Group 3 consisted of 55 negative control sera that were weekly collected during 11 weeks (from the age of 9–20 weeks) from five Chlamydia ‐free conventional bred sows (Belgian Landrace) that served as negative controls during an experimental infection experiment with C. suis strain S45 (De Clercq et al., ). Group 4 comprised of positive control sera ( n = 6) that were weekly collected during 3 weeks from two Chlamydia ‐negative conventional bred sows (Belgian Landrace) that were experimentally (combined oral, vaginal and respiratory route) infected at the age of 4 weeks with either C. suis strain H7 or C. suis strain R19.…”

Quantifying the growth ofchlamydia suisin cell culture using high‐content microscopy

“…The growth characteristics of a conjunctival (H7), respiratory (R24) and intestinal (S45) C. suis isolates were examined in six different cell lines (Table ). The strains were initially propagated in McCoy cells, using standard techniques (De Clercq et al, ; De Puysseleyr et al, ; De Puysseleyr et al ; Schautteet et al, ; Vanrompay, Ducatelle, & Haesebrouck, ) to produce a stock of each isolate.…”