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dc.contributor.authorLiu, Mengyao
dc.contributor.authorLei, Benfang
dc.date.accessioned2015-02-20T18:08:17Z
dc.date.available2015-02-20T18:08:17Z
dc.date.issued2010-08
dc.identifier.citationLiu, M., Lei. B. 2010. IgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse Polymorphonuclear Leukocytes. Open Microbiol. J., 4:20-25.en_US
dc.identifier.issn1874-2858
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/8882
dc.description.abstractThe 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.en_US
dc.subjectImmunologyen_US
dc.subjectVirologyen_US
dc.subjectCellular biologyen_US
dc.subjectHealth sciencesen_US
dc.titleIgG Endopeptidase SeMac does not Inhibit Opsonophagocytosis of Streptococcus equi Subspecies equi by Horse PolymorphonuclearLeukocytesen_US
dc.typeArticleen_US
mus.citation.extentfirstpage20en_US
mus.citation.extentlastpage25en_US
mus.citation.issue1en_US
mus.citation.journaltitleThe Open Microbiology Journalen_US
mus.citation.volume4en_US
mus.identifier.categoryHealth & Medical Sciencesen_US
mus.identifier.categoryLife Sciences & Earth Sciencesen_US
mus.identifier.doi10.2174/1874285801004010020en_US
mus.relation.collegeCollege of Letters & Scienceen_US
mus.relation.collegeCollege of Letters & Science
mus.relation.departmentMicrobiology & Immunology.en_US
mus.relation.universityMontana State University - Bozemanen_US


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