ORCID Profile
0000-0001-5058-4110
Current Organisation
Leiden University Medical Center
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Wiley
Date: 02-04-2019
Abstract: BM has been put forward as a major reservoir for memory CD8 + T cells. In order to fulfill that function, BM should “store” memory CD8 + T cells, which in biological terms would require these “stored” memory cells to be in disequilibrium with the circulatory pool. This issue is a matter of ongoing debate. Here, we unequivocally demonstrate that murine and human BM harbors a population of tissue‐resident memory CD8 + T (T RM ) cells. These cells develop against various pathogens, independently of BM infection or local antigen recognition. BM CD8 + T RM cells share a transcriptional program with resident lymphoid cells in other tissues they are polyfunctional cytokine producers and dependent on IL‐15, Blimp‐1, and Hobit. CD8 + T RM cells reside in the BM parenchyma, but are in close contact with the circulation. Moreover, this pool of resident T cells is not size‐restricted and expands upon peripheral antigenic re‐challenge. This works extends the role of the BM in the maintenance of CD8 + T cell memory to include the preservation of an expandable reservoir of functional, non‐recirculating memory CD8 + T cells, which develop in response to a large variety of peripheral antigens.
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.IMLET.2014.10.011
Abstract: The adaptive immune system consists of T and B cells that express clonally distributed antigen receptors. To achieve functional adaptive immune responses, antigen-specific T cell populations are stimulated by professional antigen-presenting cells like dendritic cells (DCs), which provide crucial stimulatory signals for efficient expansion and development of effector functions. Antigen-specific B cells receive costimulatory signals from helper T cells to stimulate affinity maturation and isotype switching. Here we elaborate on the interactions between DCs, T cells and B cells, and on the important signals for efficient induction of adaptive immune responses.
Publisher: Oxford University Press (OUP)
Date: 03-07-2015
Abstract: Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) induce effector memory T-cell expansions, which are variable and potentially depend on the age at primary exposure and coinfections. We evaluated the T-cell compartment and herpesvirus infections in 6-year-old children. T-cell subsets and immunoglobulin G seropositivity for CMV, EBV, herpes-simplex virus 1, and varicella-zoster virus were studied in 1079 6-year-old children. A random subgroup of 225 children was evaluated for CMV and EBV seropositivity before 2 years of age and for vaccination responses against measles and tetanus. CMV and EBV infections were associated with significant expansions of CD27(-) and CD27(+) effector memory T cells, respectively. These expansions were enhanced in CMV-EBV-coinfected children and were independent of varicella-zoster virus or herpes-simplex virus 1 coinfection. Naive and central memory T-cell numbers were not affected, nor were anti-tetanus and anti-measles immunoglobulin G levels. Children infected before 2 years of age showed smaller effector memory T-cell expansions than those infected between 2 and 6 years of age. CMV- and EBV-related T-cell expansions do not impair naive T-cell numbers or maintenance of protective responses against nonrelated pathogens. Duration of infection was not directly related to larger expansions of effector memory T cells in children, suggesting that other mechanisms affect these expansions at later age.
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.EXGER.2014.03.020
Abstract: Immunosenescence, defined as the age-associated dysregulation and dysfunction of the immune system, is characterized by impaired protective immunity and decreased efficacy of vaccines. An increasing number of immunological, clinical and epidemiological studies suggest that persistent Cytomegalovirus (CMV) infection is associated with accelerated aging of the immune system and with several age-related diseases. However, current evidence on whether and how human CMV (HCMV) infection is implicated in immunosenescence and in age-related diseases remains incomplete and many aspects of CMV involvement in immune aging remain controversial. The attendees of the 4th International Workshop on "CMV & Immunosenescence", held in Parma, Italy, 25-27th March, 2013, presented and discussed data related to these open questions, which are reported in this commentary.
Publisher: Public Library of Science (PLoS)
Date: 15-12-2016
Publisher: Elsevier BV
Date: 02-2016
Publisher: Springer Science and Business Media LLC
Date: 20-08-2015
Location: Netherlands
Location: United States of America
No related grants have been discovered for Ramon Arens.