scholarly journals Toll-Like Receptor 2-Dependent Activity of Native Major Outer Membrane Protein Proteosomes of Chlamydia trachomatis

2012 ◽  
Vol 81 (1) ◽  
pp. 303-310 ◽  
Author(s):  
Paola Massari ◽  
Deana N. Toussi ◽  
Delia F. Tifrea ◽  
Luis M. de la Maza
Keyword(s):  
Chlamydia Trachomatis ◽  
Epithelial Cells ◽  
Membrane Protein ◽  
Host Cell ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Major Outer Membrane Protein ◽  
Host Cells ◽  
Content Type

Chlamydia trachomatisis the most common sexually transmitted bacterial pathogen and the etiologic agent of blinding trachoma. Intracellular signaling pathways leading to host cell inflammation and innate immunity toChlamydiainclude those mediated by Toll-like receptors (TLRs) and nucleotide binding oligomerization domain 1 (Nod1) protein. In epithelial cells, TLR-dependent signaling contributes to local immune responses via induction of inflammatory mediators. There is evidence that TLR3, TLR4, and, particularly, TLR2 are critical forChlamydia-mediated host cell activation and pathology. Despite the importance of TLR2, major chlamydial TLR2 antigens have not been identified so far. Numerous bacterial porins are known TLR2 agonists, i.e., porins fromNeisseriae,Shigella,Salmonella,Haemophilus influenzae, andFusobacterium nucleatum, which share structural and functional similarities with the chlamydial major outer membrane protein (MOMP), a strong antigen candidate for a potential vaccine againstC. trachomatis. We describe the ability of purified, detergent-free MOMP to signal via TLR2in vitroin TLR-overexpressing cells and TLR2-competent human reproductive tract epithelial cell lines. Using MOMP formed in pure protein micelles (proteosomes), we show the induction of TLR2-dependent interleukin-8 (IL-8) and IL-6 secretionin vitro, the involvement of TLR1 as a TLR2 coreceptor, and the activation of both NF-κB and mitogen-activated protein (MAP) kinase intracellular pathways. Interestingly, MOMP proteosomes induce cytokine secretion in endocervical epithelial cells (End/E6E7) but not in urethral epithelial cells (THUECs). A detailed understanding of the TLR2-dependent molecular mechanisms that characterize the effect of MOMP proteosomes on host cells may provide new insights for its successful development as an immunotherapeutic target againstChlamydia.

scholarly journals Bacterial entry and intracellular processing of Neisseria gonorrhoeae in epithelial cells: immunomorphological evidence for alterations in the major outer membrane protein P.IB.

1991 ◽  
Vol 174 (3) ◽  
pp. 705-715 ◽  
Author(s):  
J F Weel ◽  
C T Hopman ◽  
J P van Putten
Keyword(s):  
Epithelial Cells ◽  
Membrane Protein ◽  
Host Cell ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Major Outer Membrane Protein ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Bacterial Invasion ◽  
Intracellular Processing

The fate of the major outer membrane protein of the gonococcus, P.IB, during the adherence, entry, and intracellular processing of the bacteria in infected epithelial cells was investigated using post-embedding immunoelectron microscopy. Various domains of the P.IB molecule were probed at different stages in the infection. These studies revealed that P.IB epitope exposure remained unaltered during the initial attachment of the bacteria to the host cells. In contrast, upon secondary attachment of the bacteria to the eukaryotic cells, apparent zones of adhesion were formed between the gonococci and the host cell membrane, which were characterized by loss of a defined P.IB epitope. These zones of adhesion with the altered P.IB immunoreactivity continued to exist and increased in number during cellular penetration, suggesting that they were essential to bacterial invasion into the eukaryotic cells. After bacterial entry, two classes of gonococci could be recognized; morphologically intact, P.IB-positive bacteria and disintegrated organisms that showed a change in, and, in a later stage, a complete loss of P.IB immunoreactivity. The intracellular alterations in the P.IB antigen could be prevented by treatment of the host cells with the lysosomotropic agent chloroquine. These observations point to a mechanism by which a subpopulation of intracellular gonococci can escape the epithelial cell defense by preventing or resisting exposure to host cell proteolytic activity.

scholarly journals Vaccination with the Recombinant Major Outer Membrane Protein Elicits Antibodies to the Constant Domains and Induces Cross-Serovar Protection against Intranasal Challenge with Chlamydia trachomatis

2013 ◽  
Vol 81 (5) ◽  
pp. 1741-1750 ◽  
Author(s):  
Delia F. Tifrea ◽  
Pooja Ralli-Jain ◽  
Sukumar Pal ◽  
Luis M. de la Maza
Keyword(s):  
Chlamydia Trachomatis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Median Number ◽  
Negative Control ◽  
Major Outer Membrane Protein ◽  
Control Groups ◽  
Content Type ◽  
Chlamydia Muridarum

ABSTRACTTo determine the ability of the major outer membrane protein (MOMP) to elicit cross-serovar protection, groups of mice were immunized by the intramuscular (i.m.) and subcutaneous (s.c.) routes with recombinant MOMP (rMOMP) fromChlamydia trachomatisserovars D (UW-3/Cx), E (Bour), or F (IC-Cal-3) orChlamydia muridarumstrain Nigg II using CpG-1826 and Montanide ISA 720 VG as adjuvants. Negative-control groups were immunized i.m. and s.c. withNeisseria gonorrhoeaerecombinant porin B (Ng-rPorB) or i.n. with Eagle's minimal essential medium (MEM-0). Following vaccination, the mice developed antibodies not only against the homologous serovar but also against heterologous serovars. The rMOMP-vaccinated animals also mounted cell-mediated immune responses as assessed by a lymphoproliferative assay. Four weeks after the last immunization, mice were challenged i.n. with 104inclusion-forming units (IFU) ofC. muridarum. The mice were weighed for 10 days and euthanized, and the number of IFU in their lungs was determined. At 10 days postinfection (p.i.), mice immunized with the rMOMP ofC. muridarumorC. trachomatisD, E, or F had lost 4%, 6%, 8%, and 8% of their initial body weight, respectively, significantly different from the negative-control groups (Ng-rPorB, 13%; MEM-0, 19%;P< 0.05). The median number of IFU recovered from the lungs of mice immunized withC. muridarumrMOMP was 0.13 × 106. The median number of IFU recovered from mice immunized with rMOMP from serovars D, E, and F were 0.38 × 106, 7.56 × 106, and 11.94 × 106IFU, respectively. All the rMOMP-immunized animals had significantly less IFU than theNg-rPorB (40 × 106)- or MEM-0 (70 × 106)-immunized mice (P< 0.05). In conclusion, vaccination with rMOMP can elicit protection against homologous and heterologousChlamydiaserovars.

scholarly journals Protection of Wild-Type and Severe Combined Immunodeficiency Mice against an Intranasal Challenge by Passive Immunization with Monoclonal Antibodies to the Chlamydia trachomatis Mouse Pneumonitis Major Outer Membrane Protein

2008 ◽  
Vol 76 (12) ◽  
pp. 5581-5587 ◽  
Author(s):  
Sukumar Pal ◽  
Jose Bravo ◽  
Ellena M. Peterson ◽  
Luis M. de la Maza
Keyword(s):  
Body Weight ◽  
Monoclonal Antibodies ◽  
Chlamydia Trachomatis ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Passive Immunization ◽  
Major Outer Membrane Protein ◽  
Wild Type

ABSTRACT Monoclonal antibodies (MAbs) to the Chlamydia trachomatis mouse pneumonitis (MoPn) major outer membrane protein (MOMP) were characterized for their ability to neutralize the infectivity of this organism in vitro and in vivo. One of the MAbs (MoPn-23) recognizes a nonlinear epitope in the MOMP, MAb MoPn-40 binds to a linear epitope in the variable domain 1 (VD1), and MAb MoPn-32 recognizes the chlamydial lipopolysaccharide. MAb MoPn-23 neutralized 50% of the infectivity of Chlamydia, as measured in vitro by using HAK (FcγIII−) and HeLa-229 (FcγIII+) cells at a concentration 100 times lower than MAb MoPn-40. MAb MoPn-32 had no neutralizing ability. In comparison to the control normal mouse immunoglobulin G, passive immunization of BALB/c mice with MAb MoPn-23 resulted in a highly significant protection against an intranasal (i.n.) challenge as determined by the change in body weight, the weight of the lungs, and the yield of Chlamydia inclusion-forming units (IFU) from the lungs. Passive immunization with MAb MoPn-40 resulted in a lower degree of protection, and MAb MoPn-32 afforded no protection. MAb MoPn-23 was also tested for its ability to protect wild-type (WT) and severe combined immunodeficient (SCID) C.B-17 mice against an i.n. challenge. Protection based on total body weight, lung weight, and yield of Chlamydia IFU was as effective in SCID as in WT C.B-17 mice. In conclusion, antibodies to MOMP can protect mice against a chlamydial infection in the presence or absence of T and B cells.

scholarly journals Anaplasma phagocytophilum Outer Membrane Protein A Interacts with Sialylated Glycoproteins To Promote Infection of Mammalian Host Cells

2012 ◽  
Vol 80 (11) ◽  
pp. 3748-3760 ◽  
Author(s):  
Nore Ojogun ◽  
Amandeep Kahlon ◽  
Stephanie A. Ragland ◽  
Matthew J. Troese ◽  
Juliana E. Mastronunzio ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Anaplasma Phagocytophilum ◽  
Protein A ◽  
Host Cells ◽  
Mammalian Host ◽  
Content Type ◽  
Outer Membrane Protein A ◽  
Sialylated Glycoproteins

ABSTRACTAnaplasma phagocytophilumis the tick-transmitted obligate intracellular bacterium that causes human granulocytic anaplasmosis (HGA).A. phagocytophilumbinding to sialyl Lewis x (sLex) and other sialylated glycans that decorate P selectin glycoprotein 1 (PSGL-1) and other glycoproteins is critical for infection of mammalian host cells. Here, we demonstrate the importance ofA. phagocytophilumouter membrane protein A (OmpA) APH_0338 in infection of mammalian host cells. OmpA is transcriptionally induced during transmission feeding ofA. phagocytophilum-infected ticks on mice and is upregulated during invasion of HL-60 cells. OmpA is presented on the pathogen's surface. Sera from HGA patients and experimentally infected mice recognize recombinant OmpA. Pretreatment ofA. phagocytophilumorganisms with OmpA antiserum reduces their abilities to infect HL-60 cells. The OmpA N-terminal region is predicted to contain the protein's extracellular domain. GlutathioneS-transferase (GST)-tagged versions of OmpA and OmpA amino acids 19 to 74 (OmpA19-74) but not OmpA75-205bind to, and competitively inhibitA. phagocytophiluminfection of, host cells. Pretreatment of host cells with sialidase or trypsin reduces or nearly eliminates, respectively, GST-OmpA adhesion. Therefore, OmpA interacts with sialylated glycoproteins. This study identifies the firstA. phagocytophilumadhesin-receptor pair and delineates the region of OmpA that is critical for infection.

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