title: Differential expression and glycosylation of anaplasma phagocytophilum major surface protein 2 paralogs during cultivation in sialyl Lewis x-deficient host cells.
abstract: Many microbial pathogens alter expression and/or posttranslational modifications of their surface proteins in response to dynamics within their host microenvironments to retain optimal interactions with their host cells and/or to evade the humoral immune response. Anaplasma phagocytophilum is an intragranulocytic bacterium that utilizes sialyl Lewis x (sLe(x))-modified P-selectin glycoprotein ligand 1 as a receptor for infecting myeloid cells. Bacterial populations that do not rely on this receptor can be obtained through cultivation in sLe(x)-defective cell lines. A. phagocytophilum major surface protein 2 [Msp2(P44)] is encoded by members of a paralogous gene family and is speculated to play roles in host adaptation. We assessed the complement of Msp2(P44) paralogs expressed by A. phagocytophilum during infection of sLe(x)-competent HL-60 cells and two HL-60 cell lines defective for sLe(x) expression. Multiple Msp2(P44) and N-terminally truncated 25- to 27-kDa isoforms having various isoelectric points and electrophoretic mobilities were expressed in each cell line. The complement of expressed msp2(p44) paralogs and the glycosyl residues modifying Msp2(P44) varied considerably among bacterial populations recovered from sLe(x)-competent and -deficient host cells. Thus, loss of host cell sLe(x) expression coincided with both differential expression and glycosylation of A. phagocytophilum Msp2(P44). This reinforces the hypothesis that this bacterium is able to generate a large variety of surface-exposed molecules that could provide great antigenic diversity and result in multiple binding properties.
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Kontos Medical Sciences Building, 1217 East Marshall Street, Room 215, Richmond, VA 23298-0678, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Troese
authors.forename: Madhubanti
authors.initials: M
authors.lastname: Sarkar
authors.forename: Nathan L
authors.initials: NL
authors.lastname: Galloway
authors.forename: Rachael J
authors.initials: RJ
authors.lastname: Thomas
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Kearns
authors.forename: Dexter V
authors.initials: DV
authors.lastname: Reneer
authors.forename: Tian
authors.initials: T
authors.lastname: Yang
authors.forename: Jason A
authors.initials: JA
authors.lastname: Carlyon
mesh_terms: D041081:Anaplasma phagocytophilum / Q000737:chemistry / Q000502:physiology*; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D002460:Cell Line; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D006031:Glycosylation; D006801:Humans; D009504:Neutrophils / Q000382:microbiology*; D009844:Oligosaccharides / Q000172:deficiency*; D020543:Proteome / Q000032:analysis; D000080506:Sialyl Lewis X Antigen
chemical_list: D001425:Bacterial Outer Membrane Proteins; D009844:Oligosaccharides; D020543:Proteome; D000080506:Sialyl Lewis X Antigen; C488283:msp2 protein, Anaplasma phagocytophilum