Publications by authors named "Samantha Drennan"

Article Synopsis
  • CD4 T cells play a crucial role in defending against viruses like SARS-CoV-2, but their response to viral mutations isn't fully understood.
  • Researchers isolated 159 CD4 T cell clones from healthcare workers infected with the original virus and identified 21 specific regions (epitopes) that these cells target in viral proteins.
  • They found that many CD4 T cell responses are specific to the virus rather than other coronaviruses, and that mutations in spikes of new variants, especially Omicron, can weaken T cell recognition, highlighting the need for ongoing monitoring of viral changes.
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Chronic lymphocytic leukemia (CLL) cells have variably low surface IgM (sIgM) levels/signaling capacity, influenced by chronic antigen engagement at tissue sites. Within these low levels, CLL with relatively high sIgM (CLLhigh) progresses more rapidly than CLL with low sIgM (CLLlow). During ibrutinib therapy, surviving CLL cells redistribute into the peripheral blood and can recover sIgM expression.

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Spontaneous regression is a recognized phenomenon in chronic lymphocytic leukemia (CLL) but its biological basis remains unknown. We undertook a detailed investigation of the biological and clinical features of 20 spontaneous CLL regression cases incorporating phenotypic, functional, transcriptomic, and genomic studies at sequential time points. All spontaneously regressed tumors were IGHV-mutated with no restricted IGHV usage or B-cell receptor (BCR) stereotypy.

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Purpose: In chronic lymphocytic leukemia (CLL), disease progression associates with surface IgM (sIgM) levels and signaling capacity. These are variably downmodulated and recover , suggesting a reversible influence of tissue-located antigen. Therapeutic targeting of sIgM function via ibrutinib, an inhibitor of Bruton tyrosine kinase (BTK), causes inhibition and tumor cell redistribution into the blood, with significant clinical benefit.

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Chronic lymphocytic leukemia (CLL) with unmutated (U-CLL) or mutated (M-CLL) immunoglobulin gene heavy-chain variable region (IGHV) displays different states of anergy, indicated by reduced surface immunoglobulin M (sIgM) levels and signaling, consequent to chronic (super)antigen exposure. The subsets also differ in the incidence of high-risk genetic aberrations and in DNA methylation profile, preserved from the maturational status of the original cell. We focused on sIgM expression and function, measured as intracellular Ca(2+) mobilization following stimulation, and probed correlations with clinical outcome.

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The presence of regulatory T (Treg) cells is thought to be an important mechanism by which head and neck squamous cell carcinoma (HNSCC) successfully evades the immune system. Using multicolour flow cytometry, the frequency and functional capacity of two CD4(+)  CD127(low/-) Treg cell populations, separated on the basis of different levels of CD25 expression (CD25(inter) and CD25(high) ), from the peripheral circulation of newly presenting HNSCC patients were assessed with regard to clinicopathological features and healthy controls. The frequency of circulating Treg cells was similar between HNSCC patients and healthy controls, and for patients with HNSCC developing from different subsites (laryngeal compared with oropharyngeal).

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