scholarly journals Increasing the Interaction of Borrelia burgdorferi with Decorin Significantly Reduces the 50 Percent Infectious Dose and Severely Impairs Dissemination

2007 ◽  
Vol 75 (9) ◽  
pp. 4272-4281 ◽  
Author(s):  
Qilong Xu ◽  
Sunita V. Seemanaplli ◽  
Kristy McShan ◽  
Fang Ting Liang
Keyword(s):  
Borrelia Burgdorferi ◽  
Severe Combined Immunodeficiency ◽  
Protein A ◽  
Antigen Expression ◽  
In Vitro Assays ◽  
Infectious Dose ◽  
Surface Antigen Expression ◽  
Immunocompetent Mice ◽  
Surface Adhesins

ABSTRACT Tight regulation of surface antigenic expression is crucial for the pathogenic strategy of the Lyme disease spirochete, Borrelia burgdorferi. Here, we report the influence of increasing expression of decorin-binding protein A (DbpA), one of the most investigated spirochetal surface adhesins, on the 50% infectious dose (ID50), dissemination, tissue colonization, pathogenicity, and persistence of B. burgdorferi in the murine host. Our in vitro assays showed that increasing DbpA expression dramatically increased the interaction of B. burgdorferi with decorin and sensitivity to growth inhibition/killing by anti-DbpA antibodies; however, this increased interaction did not affect spirochetal growth and replication in the presence of decorin. Increasing DbpA expression significantly reduced ID50 values and severely impaired dissemination in severe combined immunodeficiency (SCID) and immunocompetent mice. During infection of SCID mice, B. burgdorferi with increased DbpA expression was able to effectively colonize heart and skin tissues, but not joint tissues, completely abrogating arthritis virulence. Although increasing DbpA expression did not affect spirochetal persistence in the skin, it diminished the ability of B. burgdorferi to persist in the heart and joint tissues during chronic infection of immunocompetent mice. Taken together, the study highlights the importance of controlling surface antigen expression in the infectivity, dissemination, tissue colonization, pathogenicity, and persistence of B. burgdorferi during mammalian infection.

scholarly journals Borrelia burgdorferi Changes Its Surface Antigenic Expression in Response to Host Immune Responses

2004 ◽  
Vol 72 (10) ◽  
pp. 5759-5767 ◽  
Author(s):  
Fang Ting Liang ◽  
Jun Yan ◽  
M. Lamine Mbow ◽  
Steven L. Sviat ◽  
Robert D. Gilmore ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Immune Responses ◽  
Severe Combined Immunodeficiency ◽  
Protein A ◽  
Surface Protein ◽  
Reverse Transcription Pcr ◽  
Immune Pressure ◽  
Antigenic Expression ◽  
Immune Attack ◽  
Immunocompetent Mice

ABSTRACT The Lyme disease spirochete, Borrelia burgdorferi, causes persistent mammalian infection despite the development of vigorous immune responses against the pathogen. To examine spirochetal phenotypes that dominate in the hostile immune environment, the mRNA transcripts of four prototypic surface lipoproteins, decorin-binding protein A (DbpA), outer surface protein C (OspC), BBF01, and VlsE, were analyzed by quantitative reverse transcription-PCR under various immune conditions. We demonstrate that B. burgdorferi changes its surface antigenic expression in response to immune attack. dbpA expression was unchanged while the spirochetes decreased ospC expression by 446 times and increased BBF01 and vlsE expression up to 20 and 32 times, respectively, under the influence of immune pressure generated in immunocompetent mice during infection. This change in antigenic expression could be induced by passively immunizing infected severe combined immunodeficiency mice with specific Borrelia antisera or OspC antibody and appears to allow B. burgdorferi to resist immune attack.

Anatomic location and T-cell stimulatory functions of mouse dendritic cell subsets defined by CD4 and CD8 expression

Blood ◽  
2002 ◽  
Vol 99 (6) ◽  
pp. 2084-2093 ◽  
Author(s):  
Alexander D. McLellan ◽  
Michaela Kapp ◽  
Andreas Eggert ◽  
Christian Linden ◽  
Ursula Bommhardt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Antigen Expression ◽  
Cell Receptor ◽  
In Vitro Assays ◽  
Peptide Complexes ◽  
Marginal Zones

Abstract Mouse spleen contains CD4+, CD8α+, and CD4−/CD8α− dendritic cells (DCs) in a 2:1:1 ratio. An analysis of 70 surface and cytoplasmic antigens revealed several differences in antigen expression between the 3 subsets. Notably, the Birbeck granule–associated Langerin antigen, as well as CD103 (the mouse homologue of the rat DC marker OX62), were specifically expressed by the CD8α+ DC subset. All DC types were apparent in the T-cell areas as well as in the splenic marginal zones and showed similar migratory capacity in collagen lattices. The 3 DC subtypes stimulated allogeneic CD4+ T cells comparably. However, CD8α+ DCs were very weak stimulators of resting or activated allogeneic CD8+ T cells, even at high stimulator-to-responder ratios, although this defect could be overcome under optimal DC/T cell ratios and peptide concentrations using CD8+ F5 T-cell receptor (TCR)–transgenic T cells. CD8α− or CD8α+DCs presented alloantigens with the same efficiency for lysis by cytotoxic T lymphocytes (CTLs), and their turnover rate of class I–peptide complexes was similar, thus neither an inability to present, nor rapid loss of antigenic complexes from CD8α DCs was responsible for the low allostimulatory capacity of CD8α+ DCs in vitro. Surprisingly, both CD8α+ DCs and CD4−/CD8− DCs efficiently primed minor histocompatibility (H-Y male antigen) cytotoxicity following intravenous injection, whereas CD4+ DCs were weak inducers of CTLs. Thus, the inability of CD8α+ DCs to stimulate CD8+ T cells is limited to certain in vitro assays that must lack certain enhancing signals present during in vivo interaction between CD8α+ DCs and CD8+ T cells.

3D-microdevice for the in vivo capture of cancer-associated circulating cells.

2017 ◽  
Vol 35 (6_suppl) ◽  
pp. e579-e579
Author(s):  
Hélène Cayron ◽  
Alejandro Kayum Jiménez Zenteno ◽  
Aurore Esteve ◽  
Sylvain Sanson ◽  
Christophe Vieu ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Expression Profiles ◽  
Antigen Expression ◽  
Sampling Bias ◽  
Additional Treatment ◽  
In Vitro Assays ◽  
Major Drawback ◽  
Direct Laser

e579 Background: Circulating tumor cells (CTCs) are cancer cells that have detached from a tumor and have entered into the blood circulation at a very low concentration (D. Shook, Mech. Dev., Nov 2003). CTCs have a strong prognostic value, as their number has been correlated to overall survival in different metastatic cancers (J. S. de Bono, Clin. Cancer Res., Oct 2008). Considering the rareness of CTCs in blood, capturing them in vitro is very challenging. CTCs being mainly larger and less deformable than most of blood cells, ISET was the first system exploiting their physical traits using a filtration membrane to enrich 10mL blood samples (G. Vona, Am. J. Pathol., Jan 2000). However, placing the trapping system directly within the bloodstream would increase the amount of blood screened and ensure no sampling bias. To our knowledge, the only system developed for in vivo capture of CTCs relies on an immunologic detection targeting CTCs with specific epithelial-cell adhesion molecules (N. Saucedo-Zeni, Int. J. Oncol., Oct 2012). The major drawback of this technique is the selection bias induced, given the strong heterogeneity of antigen expression profiles in CTC population as confirmed by several studies. Methods: Our device combines the advantages of in vivo capture and physical trapping of CTCs. A polymeric 3D net-like microdevice is fabricated using a Direct Laser Writing technique (Nanoscribe) and integrated onto a Nitinol guidewire to be introduced into the basilic vein through a routine 20G catheter. To optimize the design, we conducted simulation studies and in vitro assays using a fluidic platform reproducing in vivo conditions. Results: We succeeded in capturing PC3 human prostate cancer cells from 20 mL healthy donor blood spiked with 1,000 PC3 cells in 2 minutes, demonstrating the capability to capture CTCs in conditions close to those found in vivo, in terms of pressure and flow rate and without any additional treatment or dilution of the blood. Conclusions: This device could facilitate treatment personalization and follow-up. Its versatility should render it transposable to the capture of single or clustered CTCs, derived from all types of cancer and, by extension, to other circulating cellular and molecular biomarkers.

scholarly journals Borrelia burgdorferi Escape Mutants That Survive in the Presence of Antiserum to the OspA Vaccine Are Killed When Complement Is Also Present

1998 ◽  
Vol 66 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Mónica Solé ◽  
Carlos Bantar ◽  
Karl Indest ◽  
Yan Gu ◽  
Ramesh Ramamoorthy ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Protein A ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Antibody Concentration ◽  
Initial Attempt ◽  
Outer Surface Protein A ◽  
Escape Mutants ◽  
Low Passage

ABSTRACT As an initial attempt to investigate the possible role of outer surface protein A (OspA) escape mutants of Borrelia burgdorferi in decreasing the efficacy of the OspA vaccine, mutants of the HB19 strain of B. burgdorferi sensu stricto were selected in vitro from an uncloned, low-passage-number isolate. The antiserum used for selection was obtained from rhesus monkeys that had been given a vaccine of the same formulation and dose, and by the same route of administration, as that given to humans in several trials. All of the mutants selected in liquid medium and subsequently cloned twice in solid medium expressed a single abundant protein of 28 to 34 kDa instead of both OspA and OspB. Depending on the mutant, this protein reacted strongly, weakly, or not detectably with the anti-OspA antibody used for selection. Analysis of the ospAB locus of each of four representatives from these three groups of mutants by PCR with oligonucleotide primers that hybridize to flanking regions of theospAB operon, and of the corresponding phenotype with monoclonal antibodies that bind to the amino or carboxyl terminus of the OspA or OspB polypeptide, indicated that in all cases a deletion within the operon had occurred. Spirochetes from the four mutant strains chosen for further analysis could be killed in antibody-dependent, complement-mediated killing assays with the selecting anti-OspA antibody, despite their resistance to killing with this antibody in the absence of complement. Complement-mediated killing occurred at an antibody concentration higher than that required to kill wild-type spirochetes. If anti-OspA antibody acts only within the tick, where complement is probably ineffective due to tick-derived decomplementing factors, then OspA escape mutants, if infectious, could seriously diminish the efficacy of OspA vaccines. On the other hand, if the killing of B. burgdorferi with anti-OspA antibody also takes place within the human host, then our results indicate that chimeric/deletion escape mutants will be killed as well.

scholarly journals Active and Passive Immunity against Borrelia burgdorferi Decorin Binding Protein A (DbpA) Protects against Infection

1998 ◽  
Vol 66 (5) ◽  
pp. 2143-2153 ◽  
Author(s):  
Mark S. Hanson ◽  
David R. Cassatt ◽  
Betty P. Guo ◽  
Nita K. Patel ◽  
Michael P. McCarthy ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Low Dose ◽  
Early Stage ◽  
Protein A ◽  
Sensu Stricto ◽  
Passive Immunity ◽  
In Vitro Growth

ABSTRACT Borrelia burgdorferi, the spirochete that causes Lyme disease, binds decorin, a collagen-associated extracellular matrix proteoglycan found in the skin (the site of entry for the spirochete) and in many other tissues. Two borrelial adhesins that recognize this proteoglycan, decorin binding proteins A and B (DbpA and DbpB, respectively), have recently been identified. Infection of mice by low-dose B. burgdorferi challenge elicited antibodies against DbpA and DbpB that were sustained at high levels, suggesting that these antigens are expressed in vivo. Scanning immunoelectron microscopy showed that DbpA was surface accessible on intact borreliae. Passive administration of DbpA antiserum protected mice from infection following challenge with heterologous B. burgdorferi sensu stricto isolates, even when serum administration was delayed for up to 4 days after challenge. DbpA is the first antigen target identified that is capable of mediating immune resolution of early, localizedB. burgdorferi infections. DbpA immunization also protected mice from B. burgdorferi challenge; DbpB immunization was much less effective. DbpA antiserum inhibited in vitro growth of manyB. burgdorferi sensu lato isolates of diverse geographic, phylogenetic, and clinical origins. In combination, these findings support a role for DbpA in the immunoprophylaxis of Lyme disease and suggest that DbpA vaccines have the potential to eliminate early-stageB. burgdorferi infections.

scholarly journals Trypanosoma cruzi trans-sialidase: enhancement of virulence in a murine model of Chagas' disease.

1995 ◽  
Vol 181 (5) ◽  
pp. 1693-1703 ◽  
Author(s):  
M Chuenkova ◽  
M E Pereira
Keyword(s):  
Trypanosoma Cruzi ◽  
Substrate Specificity ◽  
Chagas Disease ◽  
Severe Combined Immunodeficiency ◽  
Protein A ◽  
Inflammatory Cells ◽  
Soluble Form ◽  
Maximum Enhancement

Trypanosoma cruzi, the etiological agent of Chagas' disease, expresses a trans-sialidase at highest levels in infective trypomastigotes, where it attaches to the plasma membrane by a glycophosphoinositol linkage. Bound enzyme sheds into the extracellular milieu in a soluble form. Experiments performed in vitro suggest that the trans-sialidase participates in several parameters of T. cruzi-host interactions, like cell adhesion and complement resistance. However, the role that membrane-bound and soluble trans-sialidase plays in the infection of mammals is not understood. To begin to study the role the enzyme may play in vivo, T. cruzi trypomastigotes were inoculated subcutaneously into mice that had been sensitized for various times with the purified protein. A single dose of either endogenous or recombinant trans-sialidase injected into the connective tissues of BALB/c mice greatly enhanced parasitemia and mortality. Maximum enhancement was achieved with 1-2-h priming. Injection of the enzyme after the parasites had been established in the inoculation site had little, if any, consequence in modifying virulence. The enhancement did not seem to be through a direct effect of the enzyme on trypomastigote-host cell interactions because it occurred when the sites of trans-sialidase sensitization and parasite inoculation were physically separate. Rather, virulence enhancement seemed to depend on inflammatory cells, since priming with trans-sialidase had no significant effect in severe combined immunodeficiency mice, which lack functional T and B lymphocytes. However, antibody response to T. cruzi in the trans-sialidase-primed BALB/c mice was the same as in the control animals. Virulence enhancement was specific for the trans-sialidase because it did not occur in mice primed with Newcastle virus sialidase, which has the same substrate specificity as the T. cruzi enzyme, or with the sialidase from the bacterium Vibrio cholerae, whose substrate specificity is broader than the trypanosome sialidase. Furthermore, no enhancement of virulence occurred after sensitization with another adhesion protein (penetrin) purified from T. cruzi trypomastigotes and engineered bacteria, nor with bacterial lipopolysaccharide. The virulence-promoting activity of soluble trans-sialidase in the mouse model may be physiologically relevant because it was achieved with tiny doses, approximately 1-2 microgram/kg, raising the possibility that neutralization of the enzyme with specific probes could impair the development of Chagas' disease. In fact, a monoclonal antibody specific for the tandem repeat in the trans-sialidase COOH terminus enhanced infection of BALB/c mice, in agreement with earlier experiments in vitro, whereas antibodies against an amino acid sequence in the Cys region had the opposite effect.

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