Expression Analysis of Outer Membrane Protein HPS_06257 in Different Strains of <i>Glaesserella parasuis</i> and Its Potential Role in Protective Immune Response against HPS_06257-Expressing Strains via Antibody-Dependent Phagocytosis

HPS_06257 has been identified as an important protective antigen against <i>Glaesserella parasuis</i> infection. However, little is known about the role of HPS_06257 in the protective immune response. A whole-genome data analysis showed that among 18 isolates of <i>Glaesserella par...

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Main Authors: Xiaojun Chen, Hanye Shi, Xingyu Cheng, Xiaoxu Wang, Zongjie Li, Donghua Shao, Ke Liu, Jianchao Wei, Beibei Li, Jian Wang, Bin Zhou, Zhiyong Ma, Yafeng Qiu
Format: Article
Language:English
Published: MDPI AG 2022-07-01
Series:Veterinary Sciences
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Online Access:https://www.mdpi.com/2306-7381/9/7/342
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Summary:HPS_06257 has been identified as an important protective antigen against <i>Glaesserella parasuis</i> infection. However, little is known about the role of HPS_06257 in the protective immune response. A whole-genome data analysis showed that among 18 isolates of <i>Glaesserella parasuis</i>, 11 were positive for the <i>HPS_06257</i> gene, suggesting that not every strain contains this gene. We used PCR to investigate the presence of the <i>HPS_06257</i> gene among 13 reference strains and demonstrated that 5 strains contained the gene. A polyclonal antibody against HPS_06257 was generated with a recombinant protein to study the expression of HPS_06257 in those 13 strains. Consistent with the PCR data, five strains expressed HPS_06257, whereas eight strains were HPS_06257 null. We also compared the protective effects of HPS_06257 against an HPS_06257-expressing strain (HPS5) and an HPS_06257-null strain (HPS11). Immunization with HPS_06257 only protected against HPS5 and not HPS11. Moreover, phagocytosis of antibody-opsonized bacteria demonstrates that the antibody against HPS_06257 increased the phagocytosis of the HPS5 strain by macrophages but not the phagocytosis of the HPS11 strain, suggesting that antibody-dependent phagocytosis is responsible for the protective role exerted by HPS_06257 in the immune response to HPS5. Our data also show that the antibody against HPS_06257 increased the phagocytosis of the other HPS_06257-expressing strains by macrophages but not that of HPS_06257-null strains. In summary, our findings demonstrate that antibody-dependent phagocytosis contributes to the protective immune response induced by immunization with HPS_06257 against HPS_06257-expressing strains.
ISSN:2306-7381