scholarly journals Detection of Q Fever Specific Antibodies Using Recombinant Antigen in ELISA with Peroxidase Based Signal Amplification

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hua-Wei Chen ◽  
Zhiwen Zhang ◽  
Erin Glennon ◽  
Wei-Mei Ching
Keyword(s):  
Membrane Protein ◽  
Outer Membrane Protein ◽  
Signal Amplification ◽  
Q Fever ◽  
Recombinant Antigen ◽  
Antibody Assay ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Fever Patient ◽  
Indirect Immunofluorescent

Currently, the accepted method for Q fever serodiagnosis is indirect immunofluorescent antibody assay (IFA) using the whole cell antigen. In this study, we prepared the recombinant antigen of the 27-kDa outer membrane protein (Com1) which has been shown to be recognized by Q fever patient sera. The performance of recombinant Com1 was evaluated in ELISA by IFA confirmed serum samples. Due to the low titers of IgG and IgM in Q fever patients, the standard ELISA signals were further amplified by using biotinylated anti-human IgG or IgM plus streptavidin-HRP polymer. The modified ELISA can detect 88% (29 out of 33) of Q fever patient sera collected from Marines deployed to Iraq. Less than 5% (5 out of 156) of the sera from patients with other febrile diseases reacted with the Com1. These results suggest that the modified ELISA using Com1 may have the potential to improve the detection of Q fever specific antibodies.

scholarly journals Identification of Immunologically Relevant Proteins of Chlamydophila abortus Using Sera from Experimentally Infected Pregnant Ewes

2010 ◽  
Vol 17 (8) ◽  
pp. 1274-1281 ◽  
Author(s):  
P. X. Marques ◽  
Puneet Souda ◽  
J. O'Donovan ◽  
J. Gutierrez ◽  
E. J. Gutierrez ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Host Cells ◽  
Serum Samples ◽  
New Host ◽  
Chlamydophila Abortus ◽  
Development Cycle ◽  
Macrophage Infectivity Potentiator ◽  
Infected Cells

ABSTRACT Chlamydophila abortus is an intracellular pathogen and the etiological agent of enzootic abortion of ewes (EAE). C. abortus has a biphasic development cycle; extracellular infectious elementary bodies (EB) attach and penetrate host cells, where they give rise to intracellular, metabolically active reticulate bodies (RB). RB divide by binary fission and subsequently mature to EB, which, on rupture of infected cells, are released to infect new host cells. Pregnant ewes were challenged with 2 × 106 inclusion forming units (IFU) of C. abortus cultured in yolk sac (comprising both EB and RB). Serum samples were collected at 0, 7, 14, 21, 27, 30, 35, 40, and 43 days postinfection (dpi) and used to identify antigens of C. abortus expressed during disease. Additionally, sera from fetal lambs were collected at 30, 35, 40, and 43 dpi. All serum samples collected from experimentally infected pregnant ewes reacted specifically with several antigens of EB as determined by one-dimensional (1-D) and 2-D gel electrophoresis; reactive antigens identified by mass spectrometry included the major outer membrane protein (MOMP), polymorphic outer membrane protein (POMP), and macrophage infectivity potentiator (MIP) lipoprotein.

Specific antibodies induced by nasally administered 40-kDa outer membrane protein of Porphyromonas gingivalis inhibits coaggregation activity of P. gingivalis

Vaccine ◽  
2003 ◽  
Vol 22 (2) ◽  
pp. 250-256 ◽  
Author(s):  
Jun Namikoshi ◽  
Shigeo Otake ◽  
Satomi Maeba ◽  
Mitsuo Hayakawa ◽  
Yoshimitsu Abiko ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Porphyromonas Gingivalis ◽  
Outer Membrane Protein ◽  
Specific Antibodies

scholarly journals Cloning and Porin Activity of the Major Outer Membrane Protein P1 from Coxiella burnetii

2002 ◽  
Vol 70 (12) ◽  
pp. 6741-6750 ◽  
Author(s):  
Sunita Varghees ◽  
Kati Kiss ◽  
Giovanni Frans ◽  
Orit Braha ◽  
James E. Samuel
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Coxiella Burnetii ◽  
Outer Membrane Protein ◽  
Q Fever ◽  
Pcr Amplification ◽  
Major Outer Membrane Protein ◽  
Amino Acid Sequences ◽  
Inverse Pcr ◽  
Developmental Cycle

ABSTRACT Coxiella burnetii, the etiological agent of Q fever, is a gram-negative obligate intracellular bacterium. Two striking characteristics of this microorganism are its ability to thrive within a phagolysosome and its ability to persist in the environment outside a host cell. These abilities have been attributed to the existence of C. burnetii developmental cycle variants: large-cell variants (LCV), small-cell variants (SCV), and small dense cells (SDC). Variants differ in protein profiles, including differential expression of a major outer membrane protein (MOMP) of C. burnetii, designated P1. The ∼29-kDa MOMP is highly expressed in LCV, down-regulated in SCV, and not apparent in SDC. We sought to characterize P1 through purification of native protein for N-terminal analysis, cloning, and functional studies. Highly purified P1, extracted from C. burnetii membranes by using the zwitterionic detergent Empigen, allowed the determination of N-terminal and internal peptide sequences. The entire P1 coding locus was cloned by PCR amplification based upon these peptide sequences, followed by inverse PCR. Comparison of the predicted P1 amino acid sequences among the C. burnetii isolates Nine Mile, Koka, Scurry, and Kerns indicated a high degree of conservation. Structural prediction suggests that the peptide has a predominantly β-sheet conformation, consistent with bacterial porins. Typical porin characteristics were observed for native P1, including detergent solubilization properties, heat modification of purified protein, and channel formation in a planar lipid bilayer. Characterization of differentially expressed P1 as a porin increases our understanding of the function of morphological variants and their role in pathogenesis.

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