TargeTron inactivation of plasmid-regulated Chlamydia trachomatis CT084 results in a nonlytic phenotype.

Chlamydia trachomatis is an obligate intracellular bacterium that causes blinding trachoma and sexually transmitted disease. The chlamydial plasmid is a critical virulence factor in the pathogenesis of these diseases. Plasmid gene protein 4 (Pgp4) plays a major role in chlamydial virulence by regulating the expression of both chromosomal genes and Pgp3.

TargeTron Inactivation of Chlamydia trachomatis Results in a Lipopolysaccharide 3-Deoxy-d-Manno-Oct-2-Ulosonic Acid-Deficient Strain That Is Cytotoxic for Cells.

All members of the family Chlamydiaceae have lipopolysaccharides (LPS) that possess a shared carbohydrate trisaccharide antigen, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) that is functionally uncharacterized. A single gene, genus-specific epitope (), is responsible for attaching the tri-Kdo to lipid IVA. To investigate the function of Kdo in chlamydial host cell interactions, we made a -null strain (L2Δ) by using TargeTron mutagenesis.

Chlamydia evasion of neutrophil host defense results in NLRP3 dependent myeloid-mediated sterile inflammation through the purinergic P2X7 receptor.

Chlamydia trachomatis infection causes severe inflammatory disease resulting in blindness and infertility. The pathophysiology of these diseases remains elusive but myeloid cell-associated inflammation has been implicated. Here we show NLRP3 inflammasome activation is essential for driving a macrophage-associated endometritis resulting in infertility by using a female mouse genital tract chlamydial infection model.

A Chlamydial Plasmid-Dependent Secretion System for the Delivery of Virulence Factors to the Host Cytosol.

Chlamydia are obligate intracellular Gram-negative bacteria distinguished by a unique developmental biology confined within a parasitophorous vacuole termed an inclusion. The chlamydial plasmid is a central virulence factor in the pathogenesis of infection. Plasmid gene protein 4 (Pgp4) regulates the expression of plasmid gene protein 3 (Pgp3) and chromosomal glycogen synthase (GlgA), virulence factors secreted from the inclusion to the host cytosol by an unknown mechanism.

Chlamydia trachomatis Plasmid Gene Protein 3 Is Essential for the Establishment of Persistent Infection and Associated Immunopathology.

is an obligate intracellular bacterial pathogen that causes blinding trachoma and sexually transmitted disease afflicting hundreds of millions of people globally. A fundamental but poorly understood pathophysiological characteristic of chlamydial infection is the propensity to cause persistent infection that drives damaging inflammatory disease. The chlamydial plasmid is a virulence factor, but its role in the pathogenesis of persistent infection capable of driving immunopathology is unknown.

Chlamydia trachomatis Lipopolysaccharide Evades the Canonical and Noncanonical Inflammatory Pathways To Subvert Innate Immunity.

is the most common bacterial cause of sexually transmitted infections. sexually transmitted infections are commonly asymptomatic, implying a pathogenic strategy for the evasion of innate inflammatory immune responses, a paradox as the outer membrane contains lipopolysaccharide (LPS), a known potent agonist of inflammatory innate immunity. Here, we studied the ability of chlamydial LPS to activate the proinflammatory canonical and noncanonical inflammasome pathways in mouse bone marrow-derived macrophages (BMDM).

The Chlamydia trachomatis Plasmid and CT135 Virulence Factors Are Not Essential for Genital Tract Infection or Pathology in Female Pig-Tailed Macaques.

The plasmid and inclusion membrane protein CT135 are virulence factors in the pathogenesis of murine female genital tract infection. To determine if these virulence factors play a similar role in female nonhuman primates, we infected pig-tailed macaques with the same strains shown to be important in the murine model. Wild-type and its isogenic mutant strain deficient in both plasmid and CT135 were used to infect macaques.

Plasmid Negative Regulation of CPAF Expression Is Pgp4 Independent and Restricted to Invasive Biovars.

is an obligate intracellular bacterial pathogen that causes blinding trachoma and sexually transmitted disease. isolates are classified into 2 biovars-lymphogranuloma venereum (LGV) and trachoma-which are distinguished biologically by their natural host cell infection tropism. LGV biovars infect macrophages and are invasive, whereas trachoma biovars infect oculo-urogenital epithelial cells and are noninvasive.

Infection of Hysterectomized Mice with Chlamydia muridarum and Chlamydia trachomatis.

We studied infection and immunity of hysterectomized mice infected with and to determine if there were differences between these species in their ability to infect vaginal squamous epithelial cells independently of proximal upper genital tract tissues. We found that readily colonized and infected vaginal squamous epithelial cells, whereas did not. Primary infection of the vaginal epithelium with produced infections of a duration longer than that reported for normal mice.

Chlamydia trachomatis ChxR is a transcriptional regulator of virulence factors that function in in vivo host-pathogen interactions.

Chlamydia trachomatis is an obligate intracellular pathogen characterized by a unique biphasic developmental cycle that alternates between infectious and non-infectious organisms. Chlamydial ChxR is a transcriptional activator that has been implicated in the regulation of the development cycle. We used a reverse genetics approach to generate three chxR null mutants.

Chlamydial Protease-Like Activity Factor and Type III Secreted Effectors Cooperate in Inhibition of p65 Nuclear Translocation.

Unlabelled: The chlamydial protease-like activity factor (CPAF) is hypothesized to be an important secreted virulence factor; however, challenges in denaturing its proteolytic activity have hampered attempts to identify its legitimate targets. Here, we use a genetic and proteomic approach to identify authentic CPAF targets. Human epithelial cells infected with CPAF-sufficient and CPAF-deficient chlamydiae were lysed using known CPAF-denaturing conditions.

Chlamydial Lytic Exit from Host Cells Is Plasmid Regulated.

Unlabelled: Chlamydia trachomatis is an obligate intracellular bacterium that is a globally important human pathogen. The chlamydial plasmid is an attenuating virulence factor, but the molecular basis for attenuation is not understood. Chlamydiae replicate within a membrane-bound vacuole termed an inclusion, where they undergo a biphasic developmental growth cycle and differentiate from noninfectious into infectious organisms.

A Chlamydia trachomatis strain with a chemically generated amino acid substitution (P370L) in the cthtrA gene shows reduced elementary body production.

Background: Chlamydia (C.) trachomatis is the most prevalent bacterial sexually transmitted infection worldwide and the leading cause of preventable blindness. Genetic approaches to investigate C.

Chlamydia trachomatis virulence factor CT135 is stable in vivo but highly polymorphic in vitro.

Chlamydia trachomatis is an important human pathogen causing both ocular and sexually transmitted disease. Recently, we identified CT135 as an important virulence determinant in a mouse infection model. Results from CEL 1 digestion assays and sequencing analyses indicated that CT135 was much more polymorphic in high in vitro passage reference serovars than it was in clinical strains that had undergone limited passaging.

Transcriptional profiling of human epithelial cells infected with plasmid-bearing and plasmid-deficient Chlamydia trachomatis.

Chlamydia trachomatis is an obligate intracellular epitheliotropic bacterial pathogen of humans. Infection of the eye can result in trachoma, the leading cause of preventable blindness in the world. The pathophysiology of blinding trachoma is driven by multiple episodes of reinfection of conjunctival epithelial cells, producing an intense chronic inflammatory response resulting in submucosal tissue remodeling and scarring.

Benzylidene acylhydrazides inhibit chlamydial growth in a type III secretion- and iron chelation-independent manner.

Chlamydiae are widespread Gram-negative pathogens of humans and animals. Salicylidene acylhydrazides, developed as inhibitors of type III secretion system (T3SS) in Yersinia spp., have an inhibitory effect on chlamydial infection.

Chlamydia trachomatis polymorphic membrane protein D is a virulence factor involved in early host-cell interactions.

Chlamydia trachomatis is an obligate intracellular mucosotropic pathogen of significant medical importance. It is the etiological agent of blinding trachoma and bacterial sexually transmitted diseases, infections that afflict hundreds of millions of people globally. The C.

CD8+ T cells define an unexpected role in live-attenuated vaccine protective immunity against Chlamydia trachomatis infection in macaques.

Trachoma, caused by the obligate intracellular organism Chlamydia trachomatis, is the world's leading cause of preventable blindness for which a vaccine is needed. We have previously shown that a plasmid-deficient live-attenuated trachoma vaccine delivered ocularly to macaques elicited either solid or partial protective immunity against a virulent ocular challenge. Solidly protected macaques shared the same MHC class II alleles implicating CD4(+) T cells in superior protective immunity.

Innate immunity is sufficient for the clearance of Chlamydia trachomatis from the female mouse genital tract.

Chlamydia muridarum and Chlamydia trachomatis, mouse and human strains, respectively, have been used to study immunity in a murine model of female genital tract infection. Despite evidence that unique genes of these otherwise genomically similar strains could play a role in innate immune evasion in their respective mouse and human hosts, there have been no animal model findings to directly support this conclusion. Here, we infected C57BL/6 and adaptive immune-deficient Rag1(-/-) female mice with these strains and evaluated their ability to spontaneously resolve genital infection.

Infectivity of urogenital Chlamydia trachomatis plasmid-deficient, CT135-null, and double-deficient strains in female mice.

Chlamydia trachomatis is the most common cause of human bacterial sexually transmitted infections and is the world's leading cause of infectious preventable blindness. The chlamydial 7.5-kb plasmid and chromosomal gene CT135 have been shown to be important virulence factors in both nonhuman primate and mouse infection models.

Plasmid-mediated transformation tropism of chlamydial biovars.

Chlamydia trachomatis and C. muridarum are human and mouse pathogens, respectively, which show high conservation of gene order and content. Both species contain a common 7.

Antibody signature of spontaneous clearance of Chlamydia trachomatis ocular infection and partial resistance against re-challenge in a nonhuman primate trachoma model.

Background: Chlamydia trachomatis is the etiological agent of trachoma the world's leading cause of infectious blindness. Here, we investigate whether protracted clearance of a primary infection in nonhuman primates is attributable to antigenic variation or related to the maturation of the anti-chlamydial humoral immune response specific to chlamydial antigens.

Methodology/principal Findings: Genomic sequencing of organisms isolated throughout the protracted primary infection revealed that antigenic variation was not related to the inability of monkeys to efficiently resolve their infection.

Chlamydia trachomatis plasmid-encoded Pgp4 is a transcriptional regulator of virulence-associated genes.

Chlamydia trachomatis causes chronic inflammatory diseases of the eye and genital tract and has global medical importance. The chlamydial plasmid plays an important role in the pathophysiology of these diseases, as plasmid-deficient organisms are highly attenuated. The cryptic plasmid carries noncoding RNAs and eight conserved open reading frames (ORFs).

A live-attenuated chlamydial vaccine protects against trachoma in nonhuman primates.

Blinding trachoma is an ancient neglected tropical disease caused by Chlamydia trachomatis for which a vaccine is needed. We describe a live-attenuated vaccine that is safe and efficacious in preventing trachoma in nonhuman primates, a model with excellent predictive value for humans. Cynomolgus macaques infected ocularly with a trachoma strain deficient for the 7.

Development of a pigtail macaque model of sexually transmitted infection/HIV coinfection using Chlamydia trachomatis, Trichomonas vaginalis, and SHIV(SF162P3).

Background: Sexually transmitted infections (STIs) are associated with an increased risk of HIV infection. To model the interaction between STIs and HIV infection, we evaluated the capacity of the pigtail macaque model to sustain triple infection with Trichomonas vaginalis, Chlamydia trachomatis, and SHIV(SF162P3).

Methods: Seven SHIV(SF162P3) -infected pigtail macaques were inoculated with T.