Galactose-1-phosphate uridyltransferase (GalT), an in vivo-induced antigen of Actinobacillus pleuropneumoniae serovar 5b strain L20, provided immunoprotection against serovar 1 strain MS71

Abstract

GALT is an important antigen of Actinobacillus pleuropneumoniae (APP), which was shown to provide partial protection against APP infection in a previous study in our lab. The main purpose of the present study is to investigate GALT induced cross-protection between different APP serotypes and elucidate key mechanisms of the immune response to GALT antigenic stimulation. Bioinformatic analysis demonstrated that galT is a highly conserved gene in APP, widely distributed across multiple pathogenic strains. Homologies between any two strains ranges from 78.9% to 100% regarding the galT locus. Indirect enzyme-linked immunosorbent assay (ELISA) confirmed that GALT specific antibodies could not be induced by inactivated APP L20 or MS71 whole cell bacterin preparations. A recombinant fusion GALT protein derived from APP L20, however has proven to be an effective cross-protective antigen against APP sevorar 1 MS71 (50%, 4/8) and APP sevorar 5b L20 (75%, 6/8). Histopathological examinations have confirmed that recombinant GALT vaccinated animals showed less severe pathological signs in lung tissues than negative controls after APP challenge. Immunohistochemical (IHC) analysis indicated that the infiltration of neutrophils in the negative group is significantly increased compared with that in the normal control (P<0.001) and that in surviving animals is decreased compared to the negative group. Anti-GALT antibodies were shown to mediate phagocytosis of neutrophils. After interaction with anti-GALT antibodies, survival rate of APP challenged vaccinated animals was significantly reduced (P<0.001). This study demonstrated that GALT is an effective cross-protective antigen, which could be used as a potential vaccine candidate against multiple APP serotypes.

A detailed analysis of 16S rRNA gene sequencing and conventional PCR-based testing for the diagnosis of bacterial pathogens and discovery of novel bacteria

“…Vaccines are highly effective tools in preventing the spread of infectious diseases (Zhang et al, 2015;Zhang et al, 2018a;Zhang et al, 2018b).…”

“…Vaccines are highly effective tools in preventing the spread of infectious diseases (Zhang et al ., 2015; Zhang et al ., 2018a; Zhang et al ., 2018b). Inactivated whole-cell and recombinant subunit protein vaccines are commonly used to protect against specific pathogens (Zhang et al, 2016; Zhang et al ., 2015).…”

“…Co-infection with other bacteria or viruses can often affect the pathogenicity and persistence of APG in the host, and the environmental conditions also play a crucial role. Various studies have highlighted the importance of early diagnosis (Ali et al, 2022a; Ali et al, 2024; Ali et al, 2022b; Zhang et al, 2021) and vaccination (Quan et al, 2018; Zhang et al, 2015; Zhang et al, 2018a; Zhang et al, 2018b; Zhang et al, 2022; Zhang et al, 2023; Zhu et al, 2017) as effective tools in combating IC and preventing the infection of other pathogens.…”

Escherichia coli-derived outer membrane vesicles deliver galactose-1-phosphate uridyltransferase and yield partial protection against Actinobacillus pleuropneumoniae in mice

“…Bacterial Strains, Medium, and Culture Conditions E. coli DH5α (Biomed, China) was used for cloning of recombinant plasmids, and E. coli JC8031 (K12 ΔtolRA) strains were used to produce the recombinant OMVs displaying GalT protein encoded by the expression vectors pBAD18-Cm. E. coli BL21 producing recombinant GalT protein was constructed in our previous study [31]. APP L20 (serovar 5b reference strain) and E. coli K-88ac31 were purchased from the China Institute of Veterinary Drug Control (China).…”

“…GalT was identified as a preferentially expressed antigen during APP infection using in vivo-induced antigen technology. It has been demonstrated that GalT possesses potent immunogenicity and immune-protective efficacy, which can be considered as a potential vaccine candidate [29][30][31]. However, the subunit vaccine based on GalT needs protein purification and has to be administrated with adjuvants, which are time-consuming and costly.…”