scholarly journals Characterization of the Humoral Immune Response to Chlamydia Outer Membrane Protein 2 in Chlamydial Infection

2003 ◽  
Vol 10 (1) ◽  
pp. 103-107 ◽  
Author(s):  
I. Portig ◽  
J. C. Goodall ◽  
R. L. Bailey ◽  
J. S. H. Gaston
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Chlamydial Infection ◽  
Chlamydia Pneumoniae ◽  
Specific Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Recent Infection ◽  
Humoral Immune ◽  
Immunodominant Antigen

ABSTRACT Detection of antibodies to an outer membrane protein 2 (OMP2) by enzyme-linked immunosorbent assay (ELISA) by using either the Chlamydia trachomatis- or the Chlamydia pneumoniae-specific protein was investigated. OMP2 is an immunodominant antigen giving rise to antibody responses in humans infected with different C. trachomatis serovars (A to C and D to K) or with C. pneumoniae, which could be detected by OMP2 ELISA. OMP2 ELISA is not species specific, but antibody titers were usually higher on the homologous protein. The sensitivity of this assay was high but varied according to the “gold standard” applied. Levels of antibody to C. pneumoniae OMP2 as detected by ELISA seem to return to background or near-background values within a shorter period of time compared to antibodies to C. pneumoniae detected by microimmunofluorescence (MIF), making it more likely that positive results in ELISA reflect recent infection. Thus, OMP2 ELISA has distinct advantages over MIF and commercially available ELISAs and might be a useful tool for the serodiagnosis of chlamydial infection.

scholarly journals Analysis of the Humoral Immune Response toChlamydia Outer Membrane Protein 2

1998 ◽  
Vol 5 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Per Mygind ◽  
Gunna Christiansen ◽  
Kenneth Persson ◽  
Svend Birkelund
Keyword(s):  
Immune Response ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Humoral Immune Response ◽  
Chlamydia Pneumoniae ◽  
Chlamydia Psittaci ◽  
Enzyme Linked Immunosorbent Assay ◽  
Structural Protein ◽  
Humoral Immune

ABSTRACT The humoral immune response to Chlamydia outer membrane protein 2 (Omp2) was studied. Omp2 is a highly genus-conserved structural protein of all Chlamydia species, containing a variable N-terminal fragment. To analyze where the immunogenic parts were localized, seven highly purified truncated fusion proteins constituting different regions of the protein were produced (Chlamydia pneumoniae-Omp2aa23-aa93,Chlamydia psittaci-Omp2aa23-aa94, andChlamydia trachomatis-Omp2aa23-aa84, aa87-aa547, aa23-aa182, aa167-aa434, aa420-aa547). By an enzyme-linked immunosorbent assay with serologically defined patient sera, Omp2 was found to be a major immunogen of both C. pneumoniae andC. trachomatis infections (P ≪ 0.0001). The humoral immune responses were not confined to any particular region of the Omp2 protein, and no species-specific anti-Omp2 immunoglobulins were detected.

scholarly journals Super-Resolution Fluorescence Microscopy Reveals Clustering Behaviour of Chlamydia pneumoniae’s Major Outer Membrane Protein

Biology ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 344
Author(s):  
Amy E. Danson ◽  
Alex McStea ◽  
Lin Wang ◽  
Alice Y. Pollitt ◽  
Marisa L. Martin-Fernandez ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Chlamydia Pneumoniae ◽  
Inflammatory Diseases ◽  
Super Resolution ◽  
Homology Model ◽  
Major Outer Membrane Protein ◽  
Membrane Complex ◽  
Antimicrobial Studies

Chlamydia pneumoniae is a Gram-negative bacterium responsible for a number of human respiratory diseases and linked to some chronic inflammatory diseases. The major outer membrane protein (MOMP) of Chlamydia is a conserved immunologically dominant protein located in the outer membrane, which, together with its surface exposure and abundance, has led to MOMP being the main focus for vaccine and antimicrobial studies in recent decades. MOMP has a major role in the chlamydial outer membrane complex through the formation of intermolecular disulphide bonds, although the exact interactions formed are currently unknown. Here, it is proposed that due to the large number of cysteines available for disulphide bonding, interactions occur between cysteine-rich pockets as opposed to individual residues. Such pockets were identified using a MOMP homology model with a supporting low-resolution (~4 Å) crystal structure. The localisation of MOMP in the E. coli membrane was assessed using direct stochastic optical reconstruction microscopy (dSTORM), which showed a decrease in membrane clustering with cysteine-rich regions containing two mutations. These results indicate that disulphide bond formation was not disrupted by single mutants located in the cysteine-dense regions and was instead compensated by neighbouring cysteines within the pocket in support of this cysteine-rich pocket hypothesis.

scholarly journals Complement component C3 fixes selectively to the major outer membrane protein (MOMP) of Legionella pneumophila and mediates phagocytosis of liposome-MOMP complexes by human monocytes.

1990 ◽  
Vol 172 (4) ◽  
pp. 1201-1210 ◽  
Author(s):  
C Bellinger-Kawahara ◽  
M A Horwitz
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Legionella Pneumophila ◽  
Alternative Pathway ◽  
Major Outer Membrane Protein ◽  
Complement Component ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Monocytes ◽  
Complement Component C3

Legionella pneumophila is a facultative intracellular bacterial pathogen that parasitizes human monocytes and alveolar macrophages. Previous studies from this laboratory have shown that monocyte complement receptors CR1 and CR3 and complement component C3 in serum mediate L. pneumophila phagocytosis. In this study, we have explored C3 fixation to L. pneumophila. We developed a whole-cell enzyme-linked immunosorbent assay (ELISA) to measure C3 fixation to the bacterial surface. By this assay, C3 fixes to L. pneumophila that are opsonized in fresh nonimmune serum, and C3 fixation takes place via the alternative pathway of complement activation. Immunoblot analysis of opsonized L. pneumophila indicated that C3 fixes selectively to specific acceptor molecules of L. pneumophila. Consistent with this, when nitrocellulose blots of whole L. pneumophila or bacterial components are incubated in fresh nonimmune serum, C3 fixes exclusively to the major outer membrane protein (MOMP) of L. pneumophila, a porin; C3 does not fix to L. pneumophila LPS on these blots. To further explore the role of MOMP in C3 fixation and phagocytosis, we reconstituted purified MOMP into liposomes. By the ELISA, MOMP-liposomes, but not plain liposomes lacking MOMP, avidly fix C3. Consistent with a dominant role for MOMP in C3 fixation, MOMP-liposomes form a C3 complex of the same apparent molecular weight as whole L. pneumophila in nonimmune serum. Opsonized radioiodinated MOMP-liposomes avidly adhere to monocytes, and adherence is dose dependent upon serum. By electron microscopy, opsonized MOMP-liposomes are efficiently phagocytized by human monocytes, and phagocytosis takes place by a conventional appearing form of phagocytosis. This study demonstrates that C3 fixes selectively to the MOMP of L. pneumophila, and that, in the presence of nonimmune serum, MOMP can mediate phagocytosis of liposomes and, potentially, phagocytosis of intact L. pneumophila by human monocytes.

scholarly journals Serological Reactivity and Biochemical Characterization of Methylated and Unmethylated Forms of a Recombinant Protein Fragment Derived from Outer Membrane Protein B of Rickettsia typhi

2008 ◽  
Vol 15 (4) ◽  
pp. 684-690 ◽  
Author(s):  
Chien-Chung Chao ◽  
Zhiwen Zhang ◽  
Hui Wang ◽  
Abdulnaser Alkhalil ◽  
Wei-Mei Ching
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Mass Spectrometry Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Composition Analysis ◽  
Rickettsia Typhi ◽  
Serological Reactivity ◽  
Lysine Residues ◽  
Protein B

ABSTRACT Rickettsia typhi, an obligate intracellular bacterium that causes murine typhus, possesses a heavily methylated outer membrane protein B (OmpB) antigen. This immunodominant antigen is responsible for serological reactions and is capable of eliciting protective immune responses with a guinea pig model. Western blot analysis of partially digested OmpB with patient sera revealed that most of the reactive fragments are larger than 20 kDa. One of these fragments, which is located at the N terminus (amino acids 33 to 273), fragment A (At), has been expressed in Escherichia coli. The expressed protein (rAt) was purified by chromatography and properly refolded by sequential dialysis. The refolded rAt protein was recognized by at least 87% of the typhus group patient sera as determined by enzyme-linked immunosorbent assay (ELISA). However, the titers were lower than those obtained with OmpB of R. typhi. Since native OmpB is hypermethylated at lysine residues, we chemically methylated the lysine residues in rAt. The methylation was confirmed by amino acid composition analysis, and the methylation pattern of the methylated rAt (mrAt) protein was similar to that of native At from OmpB, as revealed by liquid chromatography-mass spectrometry analysis. Both rAt and mrAt were evaluated in an ELISA for their serological reactivity with patient sera. Among patient sera tested, 83% exhibited higher titers with mrAt than with rAt. These results suggest that rAt, with or without methylation, can potentially replace rickettsia-derived OmpB or whole-cell antigen for the diagnosis of R. typhi infection.

scholarly journals Nucleotide sequence and taxonomic value of the major outer membrane protein gene of Chlamydia pneumoniae IOL-207

1991 ◽  
Vol 137 (3) ◽  
pp. 465-475 ◽  
Author(s):  
M. W. Carter ◽  
S. A. H. Al-Mahdawi ◽  
I. G. Giles ◽  
J. D. Treharne ◽  
M. E. Ward ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Chlamydia Pneumoniae ◽  
Protein Gene ◽  
Major Outer Membrane Protein ◽  
Membrane Protein Gene

Enzyme-linked Immunosorbent Assay (ELISA) for Legionella pneumophila Using Outer Membrane Protein

1987 ◽  
Vol 61 (6) ◽  
pp. 652-661
Author(s):  
Takashige MIYAZAKI ◽  
Manabu NAKASHIMA ◽  
Shigeru KONO ◽  
Hironobu KOGA ◽  
Hiroko NAKAZATO ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Immunosorbent Assay ◽  
Outer Membrane Protein ◽  
Legionella Pneumophila ◽  
Enzyme Linked Immunosorbent Assay

scholarly journals Liposome Delivery ofChlamydia muridarumMajor Outer Membrane Protein Primes a Th1 Response That Protects against Genital Chlamydial Infection in a Mouse Model1

2008 ◽  
Vol 198 (5) ◽  
pp. 758-767 ◽  
Author(s):  
Jon Hansen ◽  
Klaus Thorleif Jensen ◽  
Frank Follmann ◽  
Else Marie Agger ◽  
Michael Theisen ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Chlamydial Infection ◽  
Th1 Response

scholarly journals Production of Chlamydia pneumoniae Proteins in Bacillus subtilis and Their Use in Characterizing Immune Responses in the Experimental Infection Model

2003 ◽  
Vol 10 (3) ◽  
pp. 367-375 ◽  
Author(s):  
Ulla Airaksinen ◽  
Tuula Penttilä ◽  
Eva Wahlström ◽  
Jenni M. Vuola ◽  
Mirja Puolakkainen ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Large Scale ◽  
Chlamydia Pneumoniae ◽  
Signal Sequence ◽  
Expression Vectors ◽  
Infection Model

ABSTRACT Due to intracellular growth requirements, large-scale cultures of chlamydiae and purification of its proteins are difficult and laborious. To overcome these problems we produced chlamydial proteins in a heterologous host, Bacillus subtilis, a gram-positive nonpathogenic bacterium. The genes of Chlamydia pneumoniae major outer membrane protein (MOMP), the cysteine-rich outer membrane protein (Omp2), and the heat shock protein (Hsp60) were amplified by PCR, and the PCR products were cloned into expression vectors containing a promoter, a ribosome binding site, and a truncated signal sequence of the α-amylase gene from Bacillus amyloliquefaciens. C. pneumoniae genes were readily expressed in B. subtilis under the control of the α-amylase promoter. The recombinant proteins MOMP and Hsp60 were purified from the bacterial lysate with the aid of the carboxy-terminal histidine hexamer tag by affinity chromatography. The Omp2 was separated as an insoluble fraction after 8 M urea treatment. The purified proteins were successfully used as immunogens and as antigens in serological assays and in a lymphoproliferation test. The Omp2 and Hsp60 antigens were readily recognized by the antibodies appearing after pulmonary infection following intranasal inoculation of C. pneumoniae in mice. Also, splenocytes collected from mice immunized with MOMP or Hsp60 proteins proliferated in response to in vitro stimulation with the corresponding proteins.

scholarly journals Chlamydia pneumoniae Major Outer Membrane Protein Is a Surface-Exposed Antigen That Elicits Antibodies Primarily Directed against Conformation-Dependent Determinants

2001 ◽  
Vol 69 (5) ◽  
pp. 3082-3091 ◽  
Author(s):  
Katerina Wolf ◽  
Elizabeth Fischer ◽  
David Mead ◽  
Guangming Zhong ◽  
Roseanna Peeling ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Chlamydia Pneumoniae ◽  
Major Outer Membrane Protein ◽  
Mass Spectrometry Analysis ◽  
Antigenic Determinants ◽  
Specific Monoclonal Antibody ◽  
Species Specific

ABSTRACT The major outer membrane protein (MOMP) of Chlamydia trachomatis serovariants is known to be an immunodominant surface antigen. Moreover, it is known that the C. trachomatis MOMP elicits antibodies that recognize both linear and conformational antigenic determinants. In contrast, it has been reported that the MOMP of Chlamydia pneumoniae is not surface exposed and is immunorecessive. We hypothesized that the discrepancies betweenC. trachomatis and C. pneumoniae MOMP exposure on intact chlamydiae and immunogenic properties might be because the focus of the host's immune response is directed to conformational epitopes of the C. pneumoniae MOMP. We therefore conducted studies aimed at defining the surface exposure of MOMP and the conformational dominance of MOMP antibodies. We present here a description of C. pneumoniaespecies-specific monoclonal antibody (MAb), GZD1E8, which recognizes a conformational epitope on the surface of C. pneumoniae. This MAb is potent in the neutralization ofC. pneumoniae infectivity in vitro. Another previously described C. pneumoniaespecies-specific monoclonal antibody, RR-402, displayed very similar characteristics. However, the antigenic determinant recognized by RR-402 has yet to be identified. We show by immunoprecipitation ofC. pneumoniae with GZD1E8 and RR-402 MAbs and by mass spectrometry analysis of immunoprecipitated proteins that both antibodies GZD1E8 and RR-402 recognize the MOMP of C. pneumoniae and that this protein is localized on the surface of the organism. We also show that human sera fromC. pneumoniae-positive donors consistently recognize the MOMP by immunoprecipitation, indicating that the MOMP ofC. pneumoniae is an immunogenic protein. These findings have potential implications for both C. pneumoniae vaccine and diagnostic assay development.

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