Natural Pig Plasma Immunoglobulins Have Anti-Bacterial Effects: Potential for Use as Feed Supplement for Treatment of Intestinal Infections in Pigs

Hedegaard, Chris J.; Strube, Mikael L.; Hansen, Marie B.; Lindved, Bodil K.; Lihme, Allan; Boye, Mette; Heegaard, Peter M. H.

To investigate if natural pig plasma immunoglobulins could interfere with bacterial adhesion to intestinal epithelium an in vitro adhesion-inhibition assay was employed using fluorescently labelled bacteria and a neonatal porcine jejunum derived cell line (IPEC-J2) as a model of the intestinal epithelium. Pre-incubation of fluorescently stained bacteria with ppIgG for 1 hour before adding the bacteria to the IPEC-J2 cells, significantly decreased adhesion of both E. coli and S. diarizonae to IPEC-J2 cells. This was observed at 1 mg/ml or more of ppIgG; at 100 mg/ ml IgG fluorescence was at background level indicating complete inhibition of adhesion ( Fig 2) . This indicates that high concentrations of natural pig immunoglobulins interfere with adhesion of both E coli and S. diarizonae to intestinal epithelial cells. reactivity against Escherichia coli and Salmonella diarizonae by competitive ELISA as described (Materials and Methods). ppIgG heated at 60°C or 70°C for 1 hour and PBS were used as control samples. The results are presented as '% inhibition' of the signal obtained in the absence of ppIgG (median values (± median ranges)). Two-way ANOVA (subjected to Bonferonni post-test) was used to observe statistical significance between the treated and untreated ppIgG (***: p<0.01; **: p<0.01).