The CD8+ T cell response to an antigen is composed of many T cell clones with unique T cell receptors, together forming a heterogeneous repertoire of effector and memory cells. How individual T cell clones contribute to this heterogeneity throughout immune responses remains largely unknown. In this study, we longitudinally track human CD8+ T cell clones expanding in response to yellow fever virus (YFV) vaccination at the single-cell level. We observed a drop in clonal diversity in blood from the acute to memory phase, suggesting that clonal selection shapes the circulating memory repertoire. Clones in the memory phase display biased differentiation trajectories along a gradient from stem cell to terminally differentiated effector memory fates. In secondary responses, YFV- and influenza-specific CD8+ T cell clones are poised to recapitulate skewed differentiation trajectories. Collectively, we show that the sum of distinct clonal phenotypes results in the multifaceted human T cell response to acute viral infections.
Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.

Anthracycline-based chemotherapies for breast cancer are known to adversely affect patients' quality of life (QOL) and immune function. For that reason, adjuvants that improve those impairments are required. A randomized double-blind study was conducted to evaluate the effectiveness of Lentinula edodes mycelia extract (LEM), which is an oral biological response modifier (BRM) medicine for cancer patients as such an adjuvant. A total of 47 breast cancer patients who were scheduled to receive postoperative adjuvant anthracycline-based chemotherapy, i.e., 5-fluorouracil (5-FU) + cyclophosphamide + epirubicin (FEC regimen), 5-FU + cyclophosphamide + doxorubicin/pirarubicin (FAC regimen), cyclophosphamide + doxorubicin/pirarubicin (AC regimen) and cyclophosphamide + epirubicin (EC regimen), were entered in the study. The patients were randomly divided into either an LEM or a placebo tablet group; the tablets were orally ingested daily over 2 courses of each therapy. In the placebo group, the total scores for QOL were lower on day 8 of the second course of chemotherapy compared with the baseline scores, whereas in the LEM group the scores had not decreased. In the placebo group, the QOL functional well-being score was lower on day 8 after both the first and second courses of chemotherapy compared with the baseline score, but it had not decreased in the LEM group. Evaluation of immunological parameters indicated that an increase in the proportion of regulatory T cells to peripheral blood CD4+ cells tended to be inhibited in the LEM group compared with the placebo group. Oral LEM that was coadministered with anthracycline-based chemotherapies was useful for maintaining patients' QOL and immune function. Thus, LEM appears to be a useful oral adjuvant for patients receiving anthracycline-based chemotherapy.

Anti-IgE therapy inhibits mast cell and basophil activation, blocks IgE binding to both FcεRI and CD23 and down regulates FcεRI expression by antigen (Ag) presenting cells (APCs). In addition to its classical role in immediate hypersensitivity, IgE has been shown in vitro to facilitate Ag presentation of allergens, whereby APC bound IgE preferentially takes up allergens for subsequent processing and presentation. The purpose of this study was to determine whether anti-IgE therapy, by blocking facilitated Ag presentation in vivo, attenuates allergen specific Th2 cell responses.
To test this hypothesis, food allergen specific T cell responses were examined during a 16-week clinical trial of omalizumab in nine subjects with eosinophilic gastroenteritis and food sensitization. Allergen specific T cell responses were measured using carboxyfluorescein succinimidyl ester dye dilution coupled with intracellular cytokine staining and polychromatic flow cytometry. Four independent indices of allergen specific T cell response (proliferation, Ag dose response, precursor frequency, and the ratio of Th2:Th1 cytokine expression) were determined.
Eight of the 9 subjects had measurable food allergen specific responses, with a median proliferation index of 112-fold. Allergen specific T cell proliferation was limited to CD4 T cells, whereas CD8 T cell did not proliferate. Food allergen specific responses were Th2 skewed relative to tetanus specific responses in the same subjects. In contradistinction to the original hypothesis, anti-IgE treatment did not diminish any of the four measured indices of allergen specific T cell response.
In sum, using multiple indices of T cell function, this study failed to demonstrate that anti-IgE therapy broadly or potently inhibits allergen specific T cell responses. As such, these data do not support a major role for IgE facilitated Ag presentation augmenting allergen specific T cell responses in vivo.
ClinicalTrials.gov identifier NCT00084097.