Sow Vaccination with a Protein Fragment against Virulent Glaesserella (Haemophilus) parasuis Modulates Immunity Traits in Their Offspring

Abstract

Glaesserella (Haemophilus) parasuis, an early colonizer of the nasal cavity in piglets, is a highly heterogeneous species, comprising both commensal and virulent strains. Virulent G. parasuis strains can cause fibrinous polyserositis called Glässer’s disease. Colostrum is a source of passive immunity for young piglets. When vaccinating sows, protective antibodies are transferred to their offspring through the colostrum. Here, sow vaccination was performed with a protein fragment, F4, from the outer membrane trimeric autotransporters VtaAs exclusively found in virulent G. parasuis. Piglets were allowed to suckle for 3 weeks, following which a challenge with two virulent strains of G. parasuis was performed. A group of nonvaccinated sows and their piglets were included as a control. Antibodies against F4 were confirmed using ELISA in the vaccinated sows and their offspring before the G. parasuis challenge. Compared to the control group, F4-vaccination also resulted in an increased level of serum TGF-β both in vaccinated sows and in their offspring at early time points of life. After the challenge, a lower body temperature and a higher weight were observed in the group of piglets from vaccinated sows. One piglet from the non-vaccinated group succumbed to the infection, but no other significant differences in clinical signs were noticed. At necropsy, performed 2 weeks after the virulent challenge, the level of surfactant protein D (SP-D) in bronchoalveolar lavage was higher in the piglets from vaccinated sows. Vaccination did not inhibit the nasal colonization of the piglets by the challenge strains.

Temporal Patterns of Phenotypic Antimicrobial Resistance and Coinfecting Pathogens in Glaesserella parasuis Strains Isolated from Diseased Swine in Germany from 2006 to 2021

“…This finding might be due to lower pathogen shedding by the sow and increased transfer of specific maternal antibodies by colostrum as a consequence of vaccination. The VtaA proteins are considered as promising vaccine candidates for future research [ 45 ]. A controlled exposure of pigs to living Gps resulted in a higher protection than vaccination, which supports the importance of interaction of the immune system with colonizing strains for protection [ 46 ].…”

Immune responses following neonatal vaccination with conserved F4 fragment of VtaA proteins from virulent Glaesserella parasuis adjuvanted with CAF®01 or CDA

“…Comparison of the amino acid sequence among the VtaAs from strains with different degrees of virulence allowed the identification of a surface-exposed fragment, named F4, within the group 1 and 2 VtaAs from the Nagasaki strain (serovar 5) that is highly conserved in virulent G. parasuis [15] . Recent work performed in our laboratory has additionally shown that sow immunization with F4 emulsified with Carbopol Polymer adjuvant not only induced anti-F4 specific immune responses but also modulated the immunity traits in their offspring with an increase of circulating TGF-β [16] .…”

“…The commercial Ingezim-Haemophilus ELISA (Ingenasa, Madrid, Spain) was used for the detection of total antibodies against G. parasuis , following the manufacturer’s indications. In addition, an in-house ELISA was used for detection of antibodies against F4 [16] . Briefly, high binding plates were coated overnight at 4 °C with 500 ng of F4 per well.…”

Sow vaccination against virulent Glaesserella parasuis shapes the nasal microbiota of their offspring

“…The experimental study was described previously by López-Serrano et al 5 and was performed under the approval of the Ethics Commission in Animal Experimentation of the Generalitat de Catalunya (Protocol number 9211) and was carried out in compliance with the ARRIVE guidelines. Briefly, four pregnant sows were included in the study based on low antibody levels against G. parasuis .…”

“…Vaccination of the sows increases the specific antibodies transferred to their offspring through colostrum intake 4 and may delay the colonization by G. parasuis 3 . Thus, sow vaccination can be a good strategy to decrease the prevalence of the virulent strains of this microorganism in the offspring, when using a vaccine that specifically targets these strains 5 .…”