Collections > Electronic Theses and Dissertations > Campylobacter rectus virulence and the effects of immunization in the pregnant mouse model

Previous studies in the mouse model have reported that maternal infection with Campylobacter rectus, a periodontal pathogen, is associated with intrauterine fetal growth restriction. To that end, we hypothesized that maternal immunization prior to challenge with C. rectus would protect the fetus from growth restriction. Prior to mating, mice in one treatment arm received immunization via an intra-chamber challenge of heat-killed C. rectus 314. On gestation day (Gd) 7.5, pregnant mice in the treatment groups received an intrachamber challenge of live C. rectus at concentrations of 109 CFU/ml. Pregnant mice were sacrificed on Gd 16.5 and fetuses evaluated for weight, and crown-rump length. Maternal serum was collected and maternal antibody response was evaluated. Fetuses from the C. rectus challenged group had shorter crown-rump lengths and weighed significantly less than the immunized group and the control group. Maternal serum of the immunized group displayed marked elevations of IgG antibody to C. rectus compared to the non-immunized and control group. In conclusion, immunization of pregnant dams with heat-killed C. rectus provides a robust maternal IgG response and protects against fetal growth restriction. In addition, C. rectus virulence factors that may have a possible role in fetal growth restriction were investigated. The genes peb4, cadF, cdtB and ciaB that have been identified as virulence genes and sequenced in other Campylobacter species were examined for their presence in C. rectus. To that end, the genome sequences of 4 Campylobacter spp. (C. jejuni, C. lari, C. coli and C. upsaliensis) were used to design degenerate oligonucleotide primers to attempt detection and isolation of these genes in C. rectus. Although a match was not found at the nucleotide level, investigation of matches at the protein level revealed similarities with cytochrome c552 of C. jejuni RM1221, NADP-dependent malic enzyme from C. fetus subsp. fetus and mannose-1-phosphate guanylyltransferase/mannose-6-phosphate isomerase from C. fetus subsp. fetus. This is significant for future attempts to obtain genomic sequences from C. rectus and warrants further study.