Publications by authors named "Stephanie Fresnay"

Article Synopsis
  • The study investigates the role of circulating T follicular helper cells (cT) in the immune response to Typhi infection, using data from a controlled human infection model.
  • Participants who did not develop typhoid disease (NoTD) showed higher frequencies of specific cT subsets (cT2 and cT17) compared to those who developed the disease (TD), particularly a week post-challenge.
  • The findings suggest that these cT subsets are associated with the production of anti-Typhi antibodies and could be crucial for developing effective vaccines against typhoid disease.
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We have previously demonstrated that Mucosal-Associated Invariant T (MAIT) cells secrete multiple cytokines after exposure to Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever in humans. However, whether cytokine secreting MAIT cells can enhance or attenuate the clinical severity of bacterial infections remain debatable.

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Objective: There are no vaccines for most of the major invasive strains causing severe infection in humans. We evaluated the specificity of adaptive T memory cell responses generated after Typhi exposure in humans against other major invasive strains sharing capacity for dissemination.

Methods: T memory cells from eleven volunteers who underwent controlled oral challenge with .

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Gastrointestinal infections by serovar Typhi (. Typhi) are rare in industrialized countries. However, they remain a major public health problem in the developing world with an estimated 26.

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Typhoid fever, caused by the human-restricted organism serovar Typhi (. Typhi), constitutes a major global health problem. The development of improved attenuated vaccines is pressing, but delayed by the lack of appropriate preclinical models.

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The live oral typhoid vaccine Ty21a elicits predominantly CD8+, as well as CD4+ T cells mediated immune responses. Clinical field studies showed that Ty21a is moderately effective against S. Typhi and S.

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Article Synopsis
  • A novel oral challenge model with wild-type Salmonella Typhi was created by the Oxford Vaccine Group, where 104 CFU of the bacteria led to 65% of participants developing typhoid fever within 6-9 days.* ! -
  • Changes in B cell subpopulations were studied in participants who either developed typhoid fever or did not, revealing reduced B cells during illness and increased plasmablasts during recovery for those who did develop the disease.* ! -
  • This research is the first to show clinical outcomes related to B cell subset changes following S. Typhi infection in humans, indicating that these immune responses are linked to the disease's onset.* !
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Background: Typhoid fever, caused by the human-restricted organism Salmonella Typhi (S. Typhi), is a major public health problem worldwide. Development of novel vaccines remains imperative, but is hampered by an incomplete understanding of the immune responses that correlate with protection.

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A new human oral challenge model with wild-type Salmonella Typhi (S. Typhi) was recently developed. In this model, ingestion of 104 CFU of Salmonella resulted in 65% of subjects developing typhoid fever (referred here as typhoid diagnosis -TD-) 5-10 days post-challenge.

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Salmonella Typhi (S. Typhi), the causative agent of typhoid fever, causes significant morbidity and mortality worldwide. Currently available vaccines are moderately efficacious, and identification of immunological responses associated with protection or disease will facilitate the development of improved vaccines.

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Bone marrow (BM) serves as a reservoir for a unique population of memory T cells with strong effector properties that make them ideal targets for cancer immunotherapy strategies. However, direct vaccination and priming of T cells within the BM of the host has never been investigated. This study evaluates the specific immune response induced via a new method of direct intra-bone marrow (IBM) vaccination in an animal model of human papillomavirus-associated cancer.

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Background: Use of a reduced-intensity conditioning regimen before an allogeneic hematopoietic cell transplantation is frequently associated with an early state of mixed hematopoietic chimerism. Such a coexistence of both host and donor hematopoietic cells may influence posttransplant alloreactivity and may affect the occurrence and severity of acute and chronic graft-versus-host disease (GVHD) as well as the intensity of the graft-versus-leukemia effect. Here we evaluated the relation between chimerism state after reduced-intensity conditioning transplantation (RICT), autoantibody production, and chronic GVHD (cGVHD)-related pathology.

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Recent evidence suggests that recipient as well as donor dendritic cell (DC) subsets are implicated in hematopoietic engraftment, graft-vs.-host disease occurrence, immune reconstitution and graft-vs.-leukemia effects observed after allogeneic hematopoietic cell transplantation.

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Background: Gene transfer using retroviral transduction offers the advantage of long-term transgene expression in developing strategies that use dendritic cells (DCs) for immunotherapy. The goal of this study was to infect DCs in an immature state in order to take advantage of their proliferating and tolerogenic potential.

Methods: Immature DCs were generated from murine bone marrow (BM) using either GM-CSF alone or GM-CSF plus IL-4.

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Background: Gene-transfer techniques are commonly employed for both in vitro and in vivo studies. However, modifications of the target cell following the introduction of the gene of interest are not often examined. These modifications can alter the immunogenicity and/or the susceptibility of the target cell to apoptosis and may produce unwanted consequences in vivo.

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