IdeE reduces the bactericidal activity of equine neutrophils for Streptococcus equi

Timoney, John F.; Yang, Jing; Liu, Jie; Mérant, Catherine

doi:10.1016/j.vetimm.2007.10.017

Cited by 18 publications

(13 citation statements)

References 19 publications

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“…recently reported that IdeE/SeMac reduces the bactericidal activity of isolated equine PMNs for S. equi [19]. Our results suggest that the inhibition of the bactericidal activity of PMNs may not be mediated by opsonophagocytosis or may be insignificant in whole blood.…”

Section: Discussionsupporting

confidence: 46%

IgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse Polymorphonuclear Leukocytes

Liu

Lei

2010

TOMICROJ

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The secreted Mac protein made by group A Streptococcus (GAS) inhibits opsonophagocytosis of GAS by human polymorphonuclear leukocytes (PMNs). This protein also has the endopeptidase activity against human immunoglobulin G (IgG), and the Cys94, His262 and Asp284 are critical for the enzymatic activity. The horse pathogen Streptococcus equi subspecies equi produces a homologue of Mac (SeMac). SeMac was characterized to determine whether SeMac has IgG endopeptidase activity and inhibits opsonophagocytosis of S. equi by horse PMNs. The gene was cloned and recombinant SeMac was overexpressed in Escherichia coli and purified to homogeneity. Mice with experimental S. equi infection and horses with strangles caused by S. equi seroconverted to SeMac, indicating that SeMac is produced in vivo during infection. SeMac has endopeptidase activity against human IgG. However, the protein just cleaves a small fraction, which may be IgG1 only, of horse IgG. Replacement of Cys102 with Ser or His272 with Ala abolishes the enzymatic activity of SeMac, and the Asp294Ala mutation greatly decreases the enzymatic activity. SeMac does not inhibit opsonophagocytosis of S. equi by horse PMNs but opsonophagocytosis of GAS by human PMNs. Thus, SeMac is a cysteine endopeptidase with a limited activity against horse IgG and must have other function.

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Section: Discussionsupporting

confidence: 46%

IgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse Polymorphonuclear Leukocytes

Liu

Lei

2010

TOMICROJ

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“…The two additional antigens in Septavacc, IdeE and IdeE2 are IgG endopeptidases, where IdeE2 has greater activity towards horse IgG. Both IdeE and IdeE2 are predicted to be secreted [16],[17] and IdeE has an antiphagocytic activity by binding directly to neutrophils [17].…”

Section: Resultsmentioning

confidence: 99%

Getting to Grips with Strangles: An Effective Multi-Component Recombinant Vaccine for the Protection of Horses from Streptococcus equi Infection

et al. 2009

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Streptococcus equi subspecies equi (S. equi) is a clonal, equine host-adapted pathogen of global importance that causes a suppurative lymphodendopathy of the head and neck, more commonly known as Strangles. The disease is highly prevalent, can be severe and is highly contagious. Antibiotic treatment is usually ineffective. Live attenuated vaccine strains of S. equi have shown adverse reactions and they suffer from a short duration of immunity. Thus, a safe and effective vaccine against S. equi is highly desirable. The bacterium shows only limited genetic diversity and an effective vaccine could confer broad protection to horses throughout the world. Welsh mountain ponies (n = 7) vaccinated with a combination of seven recombinant S. equi proteins were significantly protected from experimental infection by S. equi, resembling the spontaneous disease. Vaccinated horses had significantly reduced incidence of lymph node swelling (p = 0.0013) lymph node abscessation (p = 0.00001), fewer days of pyrexia (p = 0.0001), reduced pathology scoring (p = 0.005) and lower bacterial recovery from lymph nodes (p = 0.004) when compared with non-vaccinated horses (n = 7). Six of 7 vaccinated horses were protected whereas all 7 non-vaccinated became infected. The protective antigens consisted of five surface localized proteins and two IgG endopeptidases. A second vaccination trial (n = 7+7), in which the IgG endopeptidases were omitted, demonstrated only partial protection against S. equi, highlighting an important role for these vaccine components in establishing a protective immune response. S. equi shares >80% sequence identity with Streptococcus pyogenes. Several of the components utilized here have counterparts in S. pyogenes, suggesting that our findings have broader implications for the prevention of infection with this important human pathogen. This is one of only a few demonstrations of protection from streptococcal infection conferred by a recombinant multi-component subunit vaccine in a natural host.

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“…Phagocytosis of A. pleuropneumoniae by neutrophils was performed using a modification of a previously described procedure [13]. A. pleuropneumoniae were grown to early exponential phase and opsonized with OMP-specific rabbit antiserum (1:50) for 1 h at 37 o C. Several aliquots of neutrophils (2×10 6 ) and opsonized A. pleuropneumoniae (1×10 7 CFU) were prepared with a final volume of 1 ml for each aliquot, and control bacterial suspensions were opsonized A. pleuropneumoniae (1×10 7 CFU) with naïve rabbit serum (1:50).…”

Section: Protective Immunity Journal Of Microbiology and Modern Technmentioning

confidence: 99%

Identification of an Outer Membrane Protein from Actinobacillus Pleuropneumoniae Serotype 7

Yang¹,

L²,

Y³

2016

Journal of Microbiology and Modern Techniques

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Research Article Open AccessActinobacillus pleuropneumoniae is the etiological agent of porcine pleuropneumonia, a severe, contagious pulmonary disease that causes important economic losses in industrialized pig production worldwide. A. pleuropneumoniae is a Gram-negative bacterium of the Pasteurellaceae family [1]. The importance of the infection derives from the fact that it can result in acute, chronic, or subclinical infection, causing losses due to reduced production, and increasing costs of medication and vaccination [2]. There are two biotypes of App differentiated on the basis of their requirement for nicotinamideadenine dinucleotide (NAD Actinobacillus pleuropneumoniae causes porcine pleuropneumonia, a disease which occurs world-wide and affects pigs of all ages. The study on the protective immune mechanism is not thoroughly clear. An outer membrane protein (OMP) was identified by screening a phage library of 3~8kb random DNA fragments of A. pleuropneumonia serotype 7. The inserted segment encoding the entire amino acid sequence of the OMP was determined by sequencing the rescued plasmids and BLAST analysis. Genes encoding the OMP from the isolate were amplified from genomic DNA template by PCR and cloned into a pET15b prokaryotic expression vector, generating the pET15b-OMP. Escherichia coli BL21 (DE3) competent cells were transformed with the construct followed by the induction of protein expression by the addition of IPTG. A band corresponding to the predicted size (48.766kDa) was seen on the SDS-PAGE. Polyclonal antibodies raised against recombinant OMP from Rabbits were reacted with bacterial proteins. Immunization with the recombinant OMP showed 40% mice were protected from the challenge.

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IdeE reduces the bactericidal activity of equine neutrophils for Streptococcus equi

Cited by 18 publications

References 19 publications

IgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse Polymorphonuclear Leukocytes

IgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse Polymorphonuclear Leukocytes

Getting to Grips with Strangles: An Effective Multi-Component Recombinant Vaccine for the Protection of Horses from Streptococcus equi Infection

Identification of an Outer Membrane Protein from Actinobacillus Pleuropneumoniae Serotype 7

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