Human serum antibody response against iron-repressible outer membrane proteins ofHelicobacter pylori

ABSTRACTGram-negative bacteria produce outer membrane vesicles (OMVs) that serve a variety of functions related to survival and pathogenicity. Periplasmic and outer membrane proteins are naturally captured during vesicle formation. This property has been exploited as a method to derive immunogenic vesicle preparations for use as vaccines. In this work, we constructed aSalmonella entericaserovar Typhimurium strain that synthesized a derivative of the pneumococcal protein PspA engineered to be secreted into the periplasmic space. Vesicles isolated from this strain contained PspA in the lumen. Mice intranasally immunized with the vesicle preparation developed serum antibody responses against vesicle components that included PspA andSalmonella-derived lipopolysaccharide and outer membrane proteins, while no detectable responses developed in mice immunized with an equivalent dose of purified PspA. Mucosal IgA responses developed against theSalmonellacomponents, while the response to PspA was less apparent in most mice. Mice immunized with the vesicle preparation were completely protected against a 10× 50% lethal dose (LD50) challenge ofStreptococcus pneumoniaeand significantly protected against a 200× LD50challenge, while control mice immunized with purified PspA or empty vesicles were not protected. These results establish that vesicles can be used to mucosally deliver an antigen from a Gram-positive organism and induce a protective immune response.

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Release of Gram‐Negative Outer‐Membrane Proteins into Human Serum and Septic Rat Blood and Their Interactions with Immunoglobulin in Antiserum toEscherichia coliJ5

The Journal of Infectious Diseases ◽

10.1086/315302 ◽

2000 ◽

Vol 181 (3) ◽

pp. 1034-1043 ◽

Cited By ~ 34

Author(s):

Judith Hellman ◽

Paul M. Loiselle ◽

Emily M. Zanzot ◽

Jennifer E. Allaire ◽

Megan M. Tehan ◽

...

Keyword(s):

Membrane Proteins ◽

Human Serum ◽

Outer Membrane ◽

Outer Membrane Proteins ◽

Gram Negative ◽

Rat Blood

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Identification of Novel Antigenic Proteins in a Complex Anaplasma marginale Outer Membrane Immunogen by Mass Spectrometry and Genomic Mapping

Infection and Immunity ◽

10.1128/iai.73.12.8109-8118.2005 ◽

2005 ◽

Vol 73 (12) ◽

pp. 8109-8118 ◽

Cited By ~ 79

Author(s):

Job E. Lopez ◽

William F. Siems ◽

Guy H. Palmer ◽

Kelly A. Brayton ◽

Travis C. McGuire ◽

...

Keyword(s):

Mass Spectrometry ◽

Membrane Proteins ◽

Outer Membrane ◽

Vaccine Development ◽

Outer Membrane Proteins ◽

Serum Antibody ◽

Elongation Factor ◽

Anaplasma Marginale ◽

Antigenic Proteins ◽

Associated Proteins

ABSTRACT Immunization with purified Anaplasma marginale outer membranes induces complete protection against infection that is associated with CD4+ T-lymphocyte-mediated gamma interferon secretion and immunoglobulin G2 (IgG2) antibody titers. However, knowledge of the composition of the outer membrane immunogen is limited. Recent sequencing and annotation of the A. marginale genome predicts at least 62 outer membrane proteins (OMP), enabling a proteomic and genomic approach for identification of novel OMP by use of IgG serum antibody from outer membrane vaccinates. Outer membrane proteins were separated by two-dimensional electrophoresis, and proteins recognized by total IgG and IgG2 in immune sera of outer membrane-vaccinated cattle were detected by immunoblotting. Immunoreactive protein spots were excised and subjected to liquid chromatography-tandem mass spectrometry. A database search of the A. marginale genome identified 24 antigenic proteins that were predicted to be outer membrane, inner membrane, or membrane-associated proteins. These included the previously characterized surface-exposed outer membrane proteins MSP2, operon associated gene 2 (OpAG2), MSP3, and MSP5 as well as recently identified appendage-associated proteins. Among the 21 newly described antigenic proteins, 14 are annotated in the A. marginale genome and include type IV secretion system proteins, elongation factor Tu, and members of the MSP2 superfamily. The identification of these novel antigenic proteins markedly expands current understanding of the composition of the protective immunogen and provides new candidates for vaccine development.

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Serum Antibody Responses in Ethiopian Meningitis Patients Infected with Neisseria meningitidis Serogroup A Sequence Type 7

Clinical and Vaccine Immunology ◽

10.1128/cvi.00008-07 ◽

2007 ◽

Vol 14 (4) ◽

pp. 451-463 ◽

Cited By ~ 9

Author(s):

Gunnstein Norheim ◽

Abraham Aseffa ◽

Mohammed Ahmed Yassin ◽

Getahun Mengistu ◽

Afework Kassu ◽

...

Keyword(s):

Membrane Proteins ◽

Outer Membrane ◽

Acute Phase ◽

Outer Membrane Proteins ◽

Serum Antibody ◽

Outer Membrane Vesicles ◽

Sequence Type ◽

Enzyme Linked Immunosorbent Assay ◽

Human Complement ◽

Convalescent Phase

ABSTRACT To elucidate critical components of protective immune responses induced during the natural course of serogroup A meningococcal disease, we studied acute-, early-convalescent-, and late-convalescent-phase sera from Ethiopian patients during outbreaks in 2002 to 2003. Sera were obtained from laboratory-confirmed patients positive for serogroup A sequence type 7 (ST-7) meningococci (A:4/21:P1.20,9) (n = 71) and from Ethiopian controls (n = 113). The sera were analyzed using an enzyme-linked immunosorbent assay to measure levels of immunoglobulin G (IgG) against serogroup A polysaccharide (APS) and outer membrane vesicles (OMVs) and for serum bactericidal activity (SBA) using both rabbit and human complement sources. Despite relatively high SBA titers and high levels of IgG against APS and OMVs in acute-phase patient sera, significant increases were seen in the early convalescent phase. Antibody concentrations returned to acute-phase levels in the late convalescent phase. Considering all patients' sera, a significant but low correlation (r = 0.46) was observed between SBA with rabbit complement (rSBA) using an ST-5 reference strain and SBA with human complement (hSBA) using an ST-7 strain from Ethiopia. While rSBA demonstrated a significant linear relation with IgG against APS, hSBA demonstrated significant linear relationships with IgG against both APS and OMV. This study indicates that antibodies against both outer membrane proteins and APS may be important in providing the protection induced during disease, as measured by hSBA. Therefore, outer membrane proteins could also have a role as components of future meningococcal vaccines for the African meningitis belt.

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