title: Mycoplasma polysaccharide protects against complement.
abstract: Although they lack a cell wall, mycoplasmas do possess a glycocalyx. The interactions between the glycocalyx, mycoplasmal surface proteins and host complement were explored using the murine pathogen Mycoplasma pulmonis as a model. It was previously shown that the length of the tandem repeat region of the surface lipoprotein Vsa is associated with susceptibility to complement-mediated killing. Cells producing a long Vsa containing about 40 repeats are resistant to complement, whereas strains that produce a short Vsa of five or fewer repeats are susceptible. We show here that the length of the Vsa protein modulates the affinity of the M. pulmonis EPS-I polysaccharide for the mycoplasma cell surface, with more EPS-I being associated with mycoplasmas producing a short Vsa protein. An examination of mutants that lack EPS-I revealed that planktonic mycoplasmas were highly susceptible to complement killing even when the Vsa protein was long, demonstrating that both EPS-I and Vsa length contribute to resistance. In contrast, the mycoplasmas were resistant to complement even in the absence of EPS-I when the cells were encased in a biofilm.
authors.affiliation: Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Bolland
authors.affiliation: Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Warren L
authors.initials: WL
authors.lastname: Simmons
authors.affiliation: Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Daubenspeck
authors.affiliation: Department of Genetics, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.|Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Dybvig
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D003165:Complement System Proteins / Q000276:immunology*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D050296:Microbial Viability; D045803:Mycoplasma pulmonis / Q000737:chemistry* / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D011135:Polysaccharides, Bacterial; D003165:Complement System Proteins