Publications by authors named "Maarten E Emmelot"

Article Synopsis
  • * Despite this, the T-cell response to the Omicron BA.1 variant remains relatively intact, showing that T-cells can still recognize the virus to some extent.
  • * However, there is a significant loss of T-cell reactivity to certain important CD4 T-cell epitopes caused by mutations in the Omicron BA.1 strain, highlighting the need to track these changes in virus strains for future immunity predictions.
View Article and Find Full Text PDF

Background: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has led to considerable morbidity/mortality worldwide, but most infections, especially among children, have a mild course. However, it remains largely unknown whether infected children develop cellular immune memory.

Methods: To determine whether a memory T cell response is being developed, we performed a longitudinal assessment of the SARS-CoV-2-specific T cell response by IFN-γ ELISPOT and activation marker analyses of peripheral blood samples from unvaccinated children and adults with mild-to-moderate COVID-19.

View Article and Find Full Text PDF

Waning of the mumps virus (MuV)-specific humoral response after vaccination has been suggested as a cause for recent mumps outbreaks in vaccinated young adults, although it cannot explain all cases. Moreover, CD8 T cells may play an important role in the response against MuV; however, little is known about the characteristics and dynamics of the MuV-specific CD8 T-cell response after MuV infection. Here, we had the opportunity to follow the CD8 T-cell response to three recently identified HLA-A2*02:01-restricted MuV-specific epitopes from 1.

View Article and Find Full Text PDF

Mumps is nowadays re-emerging despite vaccination. The contribution of T cell immunity to protection against mumps has not been clearly defined. Previously, we described a set of 41 peptides that were eluted from human leukocyte antigen (HLA) class I molecules of mumps virus (MuV)-infected cells.

View Article and Find Full Text PDF

Nowadays, mumps is re-emerging in highly vaccinated populations. Waning of vaccine-induced immunity plays a role, but antigenic differences between vaccine and mumps outbreak strains could also contribute to reduced vaccine effectiveness. CD8 T cells play a critical role in immunity to viruses.

View Article and Find Full Text PDF

Background: The re-emergence of mumps among vaccinated young adults has become a global issue. Besides waning of antibody responses, suboptimal induction of T-cell responses may reduce protection. In a recent study, we observed a dominant polyfunctional CD8+ T-cell response after natural mumps virus (MuV) infection that was not present after vaccination.

View Article and Find Full Text PDF

Mumps outbreaks among vaccinated young adults stress the need for a better understanding of mumps virus (MuV)-induced immunity. Antibody responses to MuV are well characterized, but studies on T cell responses are limited. We recently isolated a MuV-specific CD4 T cell clone by stimulating peripheral blood mononuclear cells (PBMCs) from a mumps case with the viral nucleoprotein (MuV-N).

View Article and Find Full Text PDF

In the last decade, mumps virus (MuV) causes outbreaks in highly vaccinated populations. Sub-optimal T cell immunity may play a role in the susceptibility to mumps in vaccinated individuals. T cell responses to mumps virus have been demonstrated, yet the quality of the MuV-specific T cell response has not been analyzed using single cell immunological techniques.

View Article and Find Full Text PDF

Virus or tumor Ag-derived peptides that are displayed by MHC class I molecules are attractive starting points for vaccine development because they induce strong protective and therapeutic cytotoxic T cell responses. In thus study, we show that the MHC binding and consequent T cell reactivity against several HLA-A*02 restricted epitopes can be further improved through the incorporation of nonproteogenic amino acids at primary and secondary anchor positions. We screened more than 90 nonproteogenic, synthetic amino acids through a range of epitopes and tested more than 3000 chemically enhanced altered peptide ligands (CPLs) for binding affinity to HLA-A*0201.

View Article and Find Full Text PDF

Purpose: To determine the cytokine response to ocular lysates of peripheral blood mononuclear cells (PBMCs) from patients with birdshot chorioretinopathy (BSCR).

Methods: In the PBMCs of 19 patients with BSCR, T cell cytokine production in response to human retina and choroid lysates was analyzed with flow cytometry and compared to the responses against skin lysates. Five patients had active disease and had not yet been treated (naïve to systemic therapy); 14 patients had either immunomodulatory therapy (IMT) or inactive disease (referred as inactive/IMT).

View Article and Find Full Text PDF
Article Synopsis
  • Regulatory T cells (Tregs) may effectively prevent graft-versus-host disease (GVHD) after stem cell transplants, and this study explores their role in enhancing the graft-versus-tumor (GVT) effect against multiple myeloma in a specific mouse model.
  • Experiments showed that while Tregs did not hinder antitumor responses in bone marrow tumors, they suppressed responses for tumors located outside the bone marrow, indicating a unique interaction based on tumor location.
  • The research uncovered that the bone marrow's stroma can mitigate Treg's suppressive abilities, driven partly by specific cytokines, and revealed the potential conversion of Tregs into different immune cell types, suggesting new pathways for Treg-based therapies.
View Article and Find Full Text PDF

The forkhead/winged helix transcription factor (Foxp3) is expressed as two different isoforms in humans: the full-length isoform (Foxp3FL) and an alternative-splicing product lacking the exon 2 (Foxp3DeltaE2). We here studied the cellular distribution of Foxp3 isoforms by quantitative PCR and evaluated the functional outcome of retroviral transduction of Foxp3FL and Foxp3DeltaE2 genes into CD4(+)CD25(-) cells. In PBMC, both isoforms were preferentially expressed in CD4(+)CD25(hi) cells.

View Article and Find Full Text PDF

Purpose: Effective prevention of graft-versus-host disease (GvHD) is a major challenge to improve the safety of allogeneic stem cell transplantation for leukemia treatment. In murine transplantation models, administration of naturally occurring CD4+CD25+ regulatory T cells (Treg) can prevent GvHD. Toward understanding the role of human Treg in stem cell transplantation, we studied their capacity to modulate T-cell-dependent xenogeneic (x)-GvHD in a new model where x-GvHD is induced in RAG2-/-gammac-/- mice by i.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionvuaiphacuk3e2ucu0ak5fvmm8l0g7ms5): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once