S Ram

Summary

Affiliation: Boston University
Country: USA

Publications

  1. pmc A novel sialic acid binding site on factor H mediates serum resistance of sialylated Neisseria gonorrhoeae
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 187:743-52. 1998
  2. pmc Binding of complement factor H to loop 5 of porin protein 1A: a molecular mechanism of serum resistance of nonsialylated Neisseria gonorrhoeae
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases and the Evans Memorial Department of Clinical Research and Department of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 188:671-80. 1998
  3. ncbi request reprint The contrasting mechanisms of serum resistance of Neisseria gonorrhoeae and group B Neisseria meningitidis
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, MA 02118, USA
    Mol Immunol 36:915-28. 1999
  4. pmc Binding of C4b-binding protein to porin: a molecular mechanism of serum resistance of Neisseria gonorrhoeae
    S Ram
    Evans Biomedical Research Center, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 193:281-95. 2001
  5. ncbi request reprint C4bp binding to porin mediates stable serum resistance of Neisseria gonorrhoeae
    S Ram
    Evans Biomedical Research Center, Boston Medical Center, Room 604, 650 Albany Street, Boston, MA 02118, USA
    Int Immunopharmacol 1:423-32. 2001
  6. ncbi request reprint Neisserial lipooligosaccharide is a target for complement component C4b. Inner core phosphoethanolamine residues define C4b linkage specificity
    Sanjay Ram
    Section of Infectious Diseases, Evans Biomedical Research Center, Boston University Medical Center, Boston, Massachusetts 02118, USA
    J Biol Chem 278:50853-62. 2003
  7. ncbi request reprint Complement processing and immunoglobulin binding to Neisseria gonorrhoeae determined in vitro simulates in vivo effects
    D P McQuillen
    Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, 774 Albany Street, Boston, Massachusetts, USA
    J Infect Dis 179:124-35. 1999
  8. pmc Role of complement in defense of the middle ear revealed by restoring the virulence of nontypeable Haemophilus influenzae siaB mutants
    Marisol A Figueira
    Section of Pediatric Infectious Diseases, Maxwell Finland Laboratory for Infectious Diseases, Room 508, 774 Albany Street, Boston Medical Center, Boston, MA 02118, USA
    Infect Immun 75:325-33. 2007
  9. pmc Role of complement in host defense against pneumococcal otitis media
    Vishakha Sabharwal
    Section of Pediatric Infectious Diseases, Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, Boston, Massachusetts 02118, USA
    Infect Immun 77:1121-7. 2009
  10. ncbi request reprint Regulation of the mannan-binding lectin pathway of complement on Neisseria gonorrhoeae by C1-inhibitor and alpha 2-macroglobulin
    Sunita Gulati
    Section of Infectious Diseases and Hematology Oncology, Evans Biomedical Research Center, Boston University Medical Center, Boston, MA 02118, USA
    J Immunol 168:4078-86. 2002

Collaborators

Detail Information

Publications28

  1. pmc A novel sialic acid binding site on factor H mediates serum resistance of sialylated Neisseria gonorrhoeae
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 187:743-52. 1998
    ..Sialic acid can therefore bind fH uniquely through SCRs 16-20. This blocks complement pathway activation for N. gonorrhoeae at the level of C3...
  2. pmc Binding of complement factor H to loop 5 of porin protein 1A: a molecular mechanism of serum resistance of nonsialylated Neisseria gonorrhoeae
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases and the Evans Memorial Department of Clinical Research and Department of Medicine, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 188:671-80. 1998
    ..Collectively, these data provide a molecular basis to explain serum resistance of Por1A strains of N. gonorrhoeae...
  3. ncbi request reprint The contrasting mechanisms of serum resistance of Neisseria gonorrhoeae and group B Neisseria meningitidis
    S Ram
    The Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, MA 02118, USA
    Mol Immunol 36:915-28. 1999
    ..LOS structure may act in concert with capsule to prevent MAC insertion. Meningococcal strains with Class 3 Por preferentially bind factor H, suggesting Class 3 Por acts as a receptor for factor H...
  4. pmc Binding of C4b-binding protein to porin: a molecular mechanism of serum resistance of Neisseria gonorrhoeae
    S Ram
    Evans Biomedical Research Center, Boston Medical Center, Boston, Massachusetts 02118, USA
    J Exp Med 193:281-95. 2001
    ..This resulted in complete killing of these otherwise fully serum resistant strains in only 10% normal serum, underscoring the importance of C4bp in mediating gonococcal serum resistance...
  5. ncbi request reprint C4bp binding to porin mediates stable serum resistance of Neisseria gonorrhoeae
    S Ram
    Evans Biomedical Research Center, Boston Medical Center, Room 604, 650 Albany Street, Boston, MA 02118, USA
    Int Immunopharmacol 1:423-32. 2001
    ....
  6. ncbi request reprint Neisserial lipooligosaccharide is a target for complement component C4b. Inner core phosphoethanolamine residues define C4b linkage specificity
    Sanjay Ram
    Section of Infectious Diseases, Evans Biomedical Research Center, Boston University Medical Center, Boston, Massachusetts 02118, USA
    J Biol Chem 278:50853-62. 2003
    ....
  7. ncbi request reprint Complement processing and immunoglobulin binding to Neisseria gonorrhoeae determined in vitro simulates in vivo effects
    D P McQuillen
    Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, 774 Albany Street, Boston, Massachusetts, USA
    J Infect Dis 179:124-35. 1999
    ..In vitro, total IgM bound was unchanged by sialylation of SS isolates, but total C4 bound decreased by 75%, suggesting that sialylation may indirectly regulate the classical complement pathway...
  8. pmc Role of complement in defense of the middle ear revealed by restoring the virulence of nontypeable Haemophilus influenzae siaB mutants
    Marisol A Figueira
    Section of Pediatric Infectious Diseases, Maxwell Finland Laboratory for Infectious Diseases, Room 508, 774 Albany Street, Boston Medical Center, Boston, MA 02118, USA
    Infect Immun 75:325-33. 2007
    ..influenzae strains, which in turn may impact their virulence. These data demonstrate a central role for complement in innate immune defenses against NT H. influenzae infections and specifically EOM...
  9. pmc Role of complement in host defense against pneumococcal otitis media
    Vishakha Sabharwal
    Section of Pediatric Infectious Diseases, Maxwell Finland Laboratory for Infectious Diseases, Boston Medical Center, Boston, Massachusetts 02118, USA
    Infect Immun 77:1121-7. 2009
    ..Thus, limiting C3 deposition on the surface of S. pneumoniae correlates with increased incidence of EOM following NP colonization and barotrauma in the animal model...
  10. ncbi request reprint Regulation of the mannan-binding lectin pathway of complement on Neisseria gonorrhoeae by C1-inhibitor and alpha 2-macroglobulin
    Sunita Gulati
    Section of Infectious Diseases and Hematology Oncology, Evans Biomedical Research Center, Boston University Medical Center, Boston, MA 02118, USA
    J Immunol 168:4078-86. 2002
    ..Our studies indicate that MBL does not participate in complement activation on N. gonorrhoeae in the presence of "complete" serum that contains C1-inhibitor and alpha(2)-macroglobulin...
  11. pmc Multiple consecutive lavage samplings reveal greater burden of disease and provide direct access to the nontypeable Haemophilus influenzae biofilm in experimental otitis media
    Magali Leroy
    Section of Molecular Genetics, Division of Pediatric Infectious Diseases, The Maxwell Finland Laboratory for Infectious Diseases, Boston University School of Medicine, Boston Medical Center, 774 Albany Street, Boston, MA 02118, USA
    Infect Immun 75:4158-72. 2007
    ..Such findings may have direct implications for antibiotic treatment and vaccine development against NTHi...
  12. ncbi request reprint The role of porins in neisserial pathogenesis and immunity
    Paola Massari
    Department of Medicine, Division of Infectious Diseases, Boston University School of Medicine, Boston, MA 02118, USA
    Trends Microbiol 11:87-93. 2003
    ..Furthermore, neisserial porins co-localize with mitochondria of target cells, where they appear to modulate apoptosis...
  13. ncbi request reprint Factor H binding and function in sialylated pathogenic neisseriae is influenced by gonococcal, but not meningococcal, porin
    Guillermo Madico
    Evans Biomedical Research Center, Boston University Medical Center, Boston, MA 02118, USA
    J Immunol 178:4489-97. 2007
    ..Our data highlight the different mechanisms used by these two related species to evade complement...
  14. pmc The meningococcal vaccine candidate GNA1870 binds the complement regulatory protein factor H and enhances serum resistance
    Guillermo Madico
    Section of Infectious Diseases, Boston University School of Medicine, Boston, MA 02118, USA
    J Immunol 177:501-10. 2006
    ..These data provide further support for inclusion of this molecule in a meningococcal vaccine. To reflect the critical function of this molecule, we suggest calling it fH-binding protein...
  15. ncbi request reprint The Lip lipoprotein from Neisseria gonorrhoeae stimulates cytokine release and NF-kappaB activation in epithelial cells in a Toll-like receptor 2-dependent manner
    Philip L Fisette
    Division of Infectious Diseases, Department of Physiology and Biophysics, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA
    J Biol Chem 278:46252-60. 2003
    ..8/Lip in HEK cells was enhanced upon coexpression of TLR1 but not TLR6. These observations provide evidence that Lip is capable of inducing the release of inflammatory mediators from epithelial cells in a TLR2-dependent manner...
  16. pmc Human C4b-binding protein selectively interacts with Neisseria gonorrhoeae and results in species-specific infection
    Jutamas Ngampasutadol
    Section of Infectious Diseases, Department of Medicine, Boston University Medical Center, Boston, MA 02118, USA
    Proc Natl Acad Sci U S A 102:17142-7. 2005
    ..Our findings may lead to the development of better animal models for gonorrhea and may also have implications in the choice of complement sources to evaluate neisserial vaccine candidates...
  17. ncbi request reprint Human factor H interacts selectively with Neisseria gonorrhoeae and results in species-specific complement evasion
    Jutamas Ngampasutadol
    Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
    J Immunol 180:3426-35. 2008
    ..Our findings may help to improve animal models for gonorrhea while also having implications in the choice of complement sources to evaluate neisserial vaccine candidates...
  18. pmc Defining targets for complement components C4b and C3b on the pathogenic neisseriae
    Lisa A Lewis
    Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Lazare Research Building, Room 370I, 364 Plantation Street, Worcester, MA 01605, USA
    Infect Immun 76:339-50. 2008
    ..The binding of C3b and C4b to Opa provides a rationale for the recovery of predominantly "transparent" (Opa-negative) neisserial isolates from persons with invasive disease, where the bacteria encounter high levels of complement...
  19. pmc Heptose I glycan substitutions on Neisseria gonorrhoeae lipooligosaccharide influence C4b-binding protein binding and serum resistance
    Sanjay Ram
    Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Lazare Research Building, Room 322, 364 Plantation Street, Worcester, MA 01605, USA
    Infect Immun 75:4071-81. 2007
    ..This study provides mechanistic insights into how HepI LOS substitutions affect the serum resistance of N. gonorrhoeae...
  20. ncbi request reprint Interactions between Neisseria meningitidis and the complement system
    Muriel C Schneider
    Centre for Molecular Microbiology and Infection, Department of Infectious Diseases, Flowers Building, Armstrong Road, Imperial College London, London, SW7 2AZ, UK
    Trends Microbiol 15:233-40. 2007
    ..meningitidis avoids complement-mediated killing, and how polymorphisms in genes encoding human complement proteins affect susceptibility to this important human pathogen...
  21. pmc Enhanced factor H binding to sialylated Gonococci is restricted to the sialylated lacto-N-neotetraose lipooligosaccharide species: implications for serum resistance and evidence for a bifunctional lipooligosaccharide sialyltransferase in Gonococci
    Sunita Gulati
    Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
    Infect Immun 73:7390-7. 2005
    ..Thus, serum resistance mediated by sialylation of gonococcal L1 and LNT LOS occurs by different mechanisms, and specificity of factor H binding to sialylated gonococci is restricted to the LNT LOS species...
  22. ncbi request reprint Binding of the complement inhibitor C4bp to serogroup B Neisseria meningitidis
    Hanna Jarva
    Haartman Institute, Department of Bacteriology and Immunology, University of Helsinki, and Helsinki University Central Hospital, Helsinki, Finland
    J Immunol 174:6299-307. 2005
    ..PorA-expressing strains were also more resistant to C lysis than PorA-negative strains in a serum bactericidal assay. Binding of C4bp thus helps Neisseria meningitidis to escape CP complement activation...
  23. pmc Killing of dsrA mutants of Haemophilus ducreyi by normal human serum occurs via the classical complement pathway and is initiated by immunoglobulin M binding
    Malikah Abdullah
    Department of Medicine, Campus Box 7031, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
    Infect Immun 73:3431-9. 2005
    ..We speculate that an undefined neo-epitope, possibly carbohydrate, is exposed in the dsrA mutant that is recognized by naturally occurring bactericidal IgM antibodies present in human sera...
  24. ncbi request reprint Molecular characterization of the interaction between porins of Neisseria gonorrhoeae and C4b-binding protein
    Hanna Jarva
    Department of Laboratory Medicine, Division of Medical Protein Chemistry, University of Lund, Malmo, Sweden
    J Immunol 179:540-7. 2007
    ..Only those recombinant mutant C4BPs that bound to bacteria rescued them from 100% killing by rhesus serum, thereby providing a functional correlate for the binding studies and highlighting C4BP function in gonococcal serum resistance...
  25. ncbi request reprint lgtC expression modulates resistance to C4b deposition on an invasive nontypeable Haemophilus influenzae
    Derek K Ho
    Department of Pathobiology, School of Public Health and Community Medicine, University of Washington, Seattle, WA 98195, USA
    J Immunol 178:1002-12. 2007
    ..Alteration of surface glycans of NTHi may be a critical event in determining the ability of a strain to evade host defenses and cause disseminated infection...
  26. doi request reprint Complement-dependent synergistic bactericidal activity of antibodies against factor H-binding protein, a sparsely distributed meningococcal vaccine antigen
    Jo Anne Welsch
    Center for Immunobiology and Vaccine Development, Children s Hospital Oakland Research Institute, Oakland, California, USA
    J Infect Dis 197:1053-61. 2008
    ..Antibodies to factor H (fH)-binding protein (fHBP), a meningococcal vaccine antigen, activate classical complement pathway serum bactericidal activity (SBA) and block binding of the complement inhibitor fH...
  27. pmc Phenotypic and genotypic analyses of Neisseria gonorrhoeae isolates that express frequently recovered PorB PIA variable region types suggest that certain P1a porin sequences confer a selective advantage for urogenital tract infection
    Lotisha E Garvin
    Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd, Bethesda, MD 20853 4799, USA
    Infect Immun 76:3700-9. 2008
    ..The capacity of some porin types to evade a porin-specific adaptive immune response must also be considered...
  28. pmc Binding of vitronectin by the Moraxella catarrhalis UspA2 protein interferes with late stages of the complement cascade
    Ahmed S Attia
    Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390 9048, USA
    Infect Immun 74:1597-611. 2006
    ..These results indicate that binding of vitronectin by UspA2 is involved in the serum resistance of M. catarrhalis; this represents the first example of vitronectin-mediated serum resistance on a microbe...