Maternal immunity enhances systemic recall immune responses upon oral immunization of piglets with F4 fimbriae

F4 enterotoxigenic Escherichia coli (ETEC) cause diarrhoea and mortality in piglets leading to severe economic losses. Oral immunization of piglets with F4 fimbriae induces a protective intestinal immune response evidenced by an F4-specific serum and intestinal IgA response. However, successful oral immunization of pigs with F4 fimbriae in the presence of maternal immunity has not been demonstrated yet. In the present study we aimed to evaluate the effect of maternal immunity on the induction of a systemic immune response upon oral immunization of piglets. Whereas F4-specific IgG and IgA could be induced by oral immunization of pigs without maternal antibodies and by intramuscular immunization of pigs with maternal antibodies, no such response was seen in the orally immunized animals with maternal antibodies. Since maternal antibodies can mask an antibody response, we also looked by ELIspot assays for circulating F4-specific antibody secreting cells (ASCs). Enumerating the F4-specific ASCs within the circulating peripheral blood mononuclear cells, and the number of F4-specific IgA ASCs within the circulating IgA+ B-cells revealed an F4-specific immune response in the orally immunized animals with maternal antibodies. Interestingly, results suggest a more robust IgA booster response by oral immunization of pigs with than without maternal antibodies. These results demonstrate that oral immunization of piglets with F4-specific maternal antibodies is feasible and that these maternal antibodies seem to enhance the secondary systemic immune response. Furthermore, our ELIspot assay on enriched IgA+ B-cells could be used as a screening procedure to optimize mucosal immunization protocols in pigs with maternal immunity

Meckel's enterolith : a rare cause of mechanical small bowel subobstruction

Meckel's diverticulum is the most common congenital gastrointestinal malformation and may present with bleeding, obstruction and diverticulitis. Symptomatic Meckel's diverticulum is associated with age 2 cm and ectopic mucosa. Formation of enteroliths is a rare complication of Meckel's diverticulum and the majority of stones will remain in the diverticulum. Factors promoting enterolith formation through precipitation of calcium in the small intestinal alkaline environment include stasis as well as diverticular anatomy and histology. Mechanical obstruction due to liberation of enteroliths is even more rare and other mechanisms include intussusception, adhesions, volvulus and neoplasms. Visualization of enteroliths on plain abdominal films is challenging because not all stones are radiopaque. Surgical diverticulectomy or segmental bowel resection with anastomosis is preferred in case of complications. We present a case of mechanical small bowel sub-obstruction resulting from an expelled Meckel's enterolith.status: publishe

Refined Candidate Region for F4ab/ac Enterotoxigenic <i>Escherichia coli</i> Susceptibility Situated Proximal to <i>MUC13</i> in Pigs

<div><p>F4 enterotoxigenic <i>Escherichia coli</i> (F4 ETEC) are an important cause of diarrhea in neonatal and newly-weaned pigs. Based on the predicted differential O-glycosylation patterns of the 2 MUC13 variants (MUC13A and MUC13B) in F4ac ETEC susceptible and F4ac ETEC resistant pigs, the <i>MUC13</i> gene was recently proposed as the causal gene for F4ac ETEC susceptibility. Because the absence of MUC13 on Western blot from brush border membrane vesicles of F4ab/acR⁺ pigs and the absence of F4ac attachment to immunoprecipitated MUC13 could not support this hypothesis, a new GWAS study was performed using 52 non-adhesive and 68 strong adhesive pigs for F4ab/ac ETEC originating from 5 Belgian farms. A refined candidate region (chr13: 144,810,100–144,993,222) for F4ab/ac ETEC susceptibility was identified with <i>MUC13</i> adjacent to the distal part of the region. This candidate region lacks annotated genes and contains a sequence gap based on the sequence of the porcine GenomeBuild 10.2. We hypothesize that a porcine orphan gene or trans-acting element present in the identified candidate region has an effect on the glycosylation of F4 binding proteins and therefore determines the F4ab/ac ETEC susceptibility in pigs.</p></div

Absence of detection of intestinal MUC13 (lane 3) by anti-mucin 13 antibodies in the purified high molecular weight (MW) fraction of F4ab/acR⁺ BBMVs.

<p>Purification occurred by anion exchange chromatography followed by gel filtration chromatography. Strong binding of F4ac fimbriae to the high MW glycoproteins can be seen in lane 2. Lane 1: protein standard.</p

Manhattan plot obtained from the <i>P</i>-values for F4ab/ac ETEC susceptibility in 120 pigs.

<p>SNPs are plotted on the X-axis ordered by chromosomal position. Genome-wide -log(10) <i>P</i>-values adjusted to genomic control are plotted on the Y-axis.</p

Immunoblotting of F4ab/acR⁺ BBMVs with F4ac fimbriae (lane 2 and 4) or anti-MUC13 antibodies (lane 3 and 5).

<p>Proteins were separated under reducing (A) and non-reducing (B) conditions. F4ac fimbriae bound to the F4-specific high molecular weight glycoproteins (only present in F4R⁺ pigs) and several non-specific F4-binding bands <50 kDa (present in F4R⁺ and F4R⁻ pigs) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105013#pone.0105013-Nguyen1" target="_blank">[20]</a>. Anti-MUC13 antibodies recognized BBMV protein bands of 55, 47, 34 and <25 kDa under reducing and non-reducing conditions, but bands of 200, 110 kDa only under reducing conditions. Lane 1  =  protein standards.</p

Schematic representation showing the identified candidate region (chr13: 144,810,100-144,993,222) of F4ab/ac ETEC susceptibility between MARC0002946 (SNPa) and Indel <i>MUC13</i> marker on chromosome 13 (chr13: 143,780,000-145,110,000).

<p>(<b>A</b>) SNP1 (ASGA0089965), SNP2 (ASGA0091537) and SNP3 (ALGA0106330) are the most significant SNPs in the association study. MARC0002946 (SNPa) and ALGA0106230 (SNPb) are not associated with F4ab/ac ETEC susceptibility. The orange boxes represent all the annotated genes in the 1.33 Mb region of chromosome 13. The gray box represent the candidate region where no annotated genes were found during the <i>in silico</i> comparative mapping. (<b>B</b>) Schematic representation showing the genotypes of SNP1 (ASGA0089965), SNP2 (ASGA0091537) and SNP3 (ALGA0106330) of 68 strong adhesive (F4R⁺) and 52 non-adhesive (F4R⁻) for F4ab/ac ETEC. For SNP1 and SNP3, the dark green boxes represent CC genotype, light green boxes represent CT genotype and red boxes represent TT genotype. For SNP2, the dark green boxes represent TT genotype, light green boxes represent CT genotype and red boxes represent CC genotype. Pig 40 (F4aR⁺) and pig 3 (F4R⁻) show different genotypes for the markers than expected.</p