Flexible RSV Prefusogenic Fusion Glycoprotein Exposes Multiple Neutralizing Epitopes that May Collectively Contribute to Protective Immunity.

Human respiratory syncytial virus (RSV) is a cause of lower respiratory tract infection in infants, young children, and older adults. There is no licensed vaccine and prophylactic treatment options are limited. The RSV fusion (F) glycoprotein is a target of host immunity and thus a focus for vaccine development.

LCAT, ApoD, and ApoA1 Expression and Review of Cholesterol Deposition in the Cornea.

Lecithin:cholesterol acyltransferase (LCAT) is an enzyme secreted by the liver and circulates with high-density lipoprotein (HDL) in the blood. The enzyme esterifies plasma cholesterol and increases the capacity of HDL to carry and potentially remove cholesterol from tissues. Cholesterol accumulates within the extracellular connective tissue matrix of the cornea stroma in individuals with genetic deficiency of LCAT.

Macrophages Shed Excess Cholesterol in Unique Extracellular Structures Containing Cholesterol Microdomains.

Objective: Cells use various mechanisms to maintain cellular cholesterol homeostasis including efflux of cholesterol from the cellular plasma membrane to cholesterol acceptors such as HDLs (high-density lipoproteins). Little is known about the transfer of cholesterol from cells into the extracellular matrix. Using a unique monoclonal antibody that detects ordered cholesterol arrays (ie, cholesterol micro[or nano]-domains), we previously identified that particles containing these cholesterol domains accumulate in the extracellular matrix during cholesterol enrichment of human monocyte-derived macrophages and are found in atherosclerotic lesions.

Siglec genes confer resistance to systemic lupus erythematosus in humans and mice.

A recent meta-analysis revealed the contribution of the SIGLEC6 locus to the risk of developing systemic lupus erythematosus (SLE). However, no specific Siglec (sialic acid-binding immunoglobulin-like lectin) genes (Siglecs) have been implicated in the pathogenesis of SLE. Here, we performed in silico analysis of the function of three major protective alleles in the locus and found that these alleles were expression quantitative trait loci that enhanced expression of the adjacent SIGLEC12 gene.

The Chlamydia pneumoniae Inclusion Membrane Protein Cpn1027 Interacts with Host Cell Wnt Signaling Pathway Regulator Cytoplasmic Activation/Proliferation-Associated Protein 2 (Caprin2).

We previously identified hypothetical protein Cpn1027 as a novel inclusion membrane protein that is unique to Chlamydia pneumoniae. In the current study, using a yeast-two hybrid screen assay, we identified host cell cytoplasmic activation/proliferation-associated protein 2 (Caprin2) as an interacting partner of Cpn1027. The interaction was confirmed and mapped to the C-termini of both Cpn1027 and Caprin2 using co-immunoprecipitation and GST pull-down assays.

The chlamydial periplasmic stress response serine protease cHtrA is secreted into host cell cytosol.

Background: The periplasmic High Temperature Requirement protein A (HtrA) plays important roles in bacterial protein folding and stress responses. However, the role of chlamydial HtrA (cHtrA) in chlamydial pathogenesis is not clear.

Results: The cHtrA was detected both inside and outside the chlamydial inclusions.

Multi-genome identification and characterization of chlamydiae-specific type III secretion substrates: the Inc proteins.

Background: Chlamydiae are obligate intracellular bacteria that multiply in a vacuolar compartment, the inclusion. Several chlamydial proteins containing a bilobal hydrophobic domain are translocated by a type III secretion (TTS) mechanism into the inclusion membrane. They form the family of Inc proteins, which is specific to this phylum.

Secretion of the chlamydial virulence factor CPAF requires the Sec-dependent pathway.

The chlamydial protease/proteasome-like activity factor (CPAF) is secreted into the host cytosol to degrade various host factors that benefit chlamydial intracellular survival. Although the full-length CPAF is predicted to contain a putative signal peptide at its N terminus, the secretion pathway of CPAF is still unknown. Here, we have provided experimental evidence that the N-terminal sequence covering the M1-G31 region was cleaved from CPAF during chlamydial infection.

Autoprocessing and self-activation of the secreted protease CPAF in Chlamydia-infected cells.

The Chlamydia-secreted protease/proteasome-like activity factor (CPAF) is synthesized as a proenzyme (proCPAF) and requires processing for proteolytic activity. Recent structural studies have further demonstrated that CPAF is a serine protease that can undergo autoprocessing and self-activation in a concentration-dependent manner in vitro. However, it is not known how CPAF is processed and activated during chlamydial infection.

Characterization of the hypothetical protein Cpn1027, a newly identified inclusion membrane protein unique to Chlamydia pneumoniae.

The hypothetical protein Cpn1027 was detected in the inclusion membrane of Chlamydia pneumoniae-infected cells with antibodies raised with Cpn1027 fusion proteins in an indirect immunofluorescence assay. The inclusion membrane staining by the anti-Cpn1027 antibodies co-localized with the staining of an antibody recognizing a known inclusion membrane protein designated IncA and these membrane stainings were blocked by the corresponding but not irrelevant fusion proteins. Although Cpn1027 was not predicted to be an inclusion membrane protein, it contained a bi-lobed hydrophobic domain region at its N-terminus, a signature secondary structural motif possessed by most chlamydial inclusion membrane proteins.

Localization of the hypothetical protein Cpn0585 in the inclusion membrane of Chlamydia pneumoniae-infected cells.

Cpn0585, encoded by a hypothetical open reading frame in Chlamydia pneumoniae genome, was detected in the inclusion membrane during C. pneumoniae infection using both polyclonal and monoclonal antibodies raised with Cpn0585 fusion protein. The anti-Cpn0585 antibodies specifically recognized the endogenous Cpn0585 without cross-reacting with IncA (a known inclusion membrane protein of C.

Hypothetical protein Cpn0308 is localized in the Chlamydia pneumoniae inclusion membrane.

The hypothetical protein encoded by Chlamydia pneumoniae open reading frame cpn0308 was detected in inclusion membranes of C. pneumoniae-infected cells using antibodies raised with Cpn0308 fusion proteins. The anti-Cpn0308 antibodies did not cross-react with IncA, a known C.

Localization of the hypothetical protein Cpn0797 in the cytoplasm of Chlamydia pneumoniae-infected host cells.

Using antibodies raised with chlamydial fusion proteins, we have localized a protein encoded by the hypothetical open reading frame Cpn0797 in the cytoplasm of Chlamydia pneumoniae-infected host cells. The anti-Cpn0797 antibodies specifically recognized Cpn0797 protein without cross-reacting with either CPAFcp or Cpn0796, the only two proteins known to be secreted into the host cell cytosol by C. pneumoniae organisms.