Thymic Rejuvenation: Are We There Yet?

Vaccination is an appealing form of immunotherapy for frail senior patients. However, several studies have shown that in contrast to younger adults, older patients do not effectively respond to vaccines. This phenomenon is greatly attributed to immunosenescence, a hallmark of aging defined by a general decline in immunity caused by thymic involution. Historically, the study of thymic involution brought to attention several factors and components involved in thymopoiesis, as contributors to the phenomena. Depicting the underlying cause(s) of the dramatic changes in the production and properties of the naïve T-cell pool in the event of acute thymic injury or due to inovulation can therefore, help focus the efforts on the best strategy to reverse or overcome these hurdles. Here, we discuss some of the well-studied approaches for rejuvenating the thymus, and introduce interleukin-(IL) 21 as the most recent thymo-stimulatory agent in the field

Examining the Counseling Needs of COVID-19 Hotline Callers: A Summative Content Analysis

Background: It is important to provide reliable information to people during a pandemic to prevent social fear. In this regard, the present study investigates the counseling needs of people who call the COVID-19 hotline in Yazd Province, Iran. Materials and Methods: In this qualitative study, the summative content analysis method was used. Due to possible changes in the counseling needs of the callers over time, the researchers first randomly checked 5% of all calls received each day. Data saturation was obtained by examining 5% of calls that were randomly selected. After reading the recorded interviews, the selected words were counted and entered into an Excel file. The keywords were then ranked. All keywords that seemed to have similar content were placed in related groups.  Results: A total of 1023 audio files were analyzed. About 1279 analysis units were extracted and categorized into 17 sub-categories and 4 main categories. Among these, 80% of the obtained analyzed units were assigned to 8 subclasses, namely counseling needs regarding the symptoms of the disease (35.97%), patient care at home (9.38%), ways of disease transmission (7.27%), centers that provide services to patients (5.94%), fear of visiting medical centers (5.79%), reports of non-compliance with health protocols (5.55%), personal protective equipment (5.32%), disinfection of equipment and food (5.08%) were included. Conclusion: Establishing a hotline during an epidemic is an easy and quick method. One of the missing links in such systems is the existence of a monitoring team and a suitable content production team. It is necessary to hear the calls received simultaneously or daily by a scientific committee and provide feedback to the respondents to identify the counseling needs of the community members

Interleukin-21 promotes thymopoiesis recovery following hematopoietic stem cell transplantation

Abstract Background Impaired T cell reconstitution remains a major deterrent in the field of bone marrow (BM) transplantation (BMT) due to pre-conditioning-induced damages inflicted to the thymi of recipient hosts. Given the previously reported thymo-stimulatory property of interleukin (IL)-21, we reasoned that its use post-BMT could have a profound effect on de novo T cell development. Methods To evaluate the effect of IL-21 on de novo T cell development in vivo, BM derived from RAG2p-GFP mice was transplanted into LP/J mice. Lymphocyte reconstitution was first assessed using a hematological analyzer and a flow cytometer on collected blood samples. Detailed flow cytometry analysis was then performed on the BM, thymus, and spleen of transplanted animals. Finally, the effect of human IL-21 on thymopoiesis was validated in humanized mice. Results Using a major histocompatibility complex (MHC)-matched allogeneic BMT model, we found that IL-21 administration improves immune reconstitution by triggering the proliferation of BM Lin−Sca1+c-kit+ (LSK) subsets. The pharmacological effect of IL-21 also culminates in the recovery of both hematopoietic (thymocytes) and non-hematopoietic (stromal) cells within the thymi of IL-21-treated recipient animals. Although T cells derived from all transplanted groups proliferate, secrete various cytokines, and express granzyme B similarly in response to T cell receptor (TCR) stimulation, full regeneration of peripheral naïve CD4+ and CD8+ T cells and normal TCRvβ distribution could only be detected in IL-21-treated recipient mice. Astonishingly, none of the recipient mice who underwent IL-21 treatment developed graft-versus-host disease (GVHD) in the MHC-matched allogeneic setting while the graft-versus-tumor (GVT) effect was strongly retained. Inhibition of GVHD onset could also be attributed to the enhanced generation of regulatory B cells (B10) observed in the IL-21, but not PBS, recipient mice. We also tested the thymopoiesis-stimulating property of human IL-21 in NSG mice transplanted with cord blood (CB) and found significant improvement in de novo human CD3+ T cell development. Conclusions In sum, our study indicates that IL-21 represents a new class of unforeseen thymopoietin capable of restoring thymic function following BMT

Additional file 1: Figure S1. of Interleukin-21 promotes thymopoiesis recovery following hematopoietic stem cell transplantation

Gating strategies for LSKs. BM cells collected from WT or IL-21R−/− C57BL/6 mice were treated in vitro for proliferation, then stained with the Lin−Sca1+c-kit+ antibody cocktail prior to Ki-67+ incorporation analysis. All described experiments were conducted at least three times with n = 5/group. Figure S2. Functional characterization of T cells. (A) Representative cell trace dilution analysis on CD4+ or CD8+ T cells derived from ctl (unirradiated), PBS-treated, or IL-21-treated LP/J recipient mice. (B) Cytokine quantification by ELISA from T cells derived from the same groups described in panel (A). (C) Representative flow cytometry analysis of granzyme B expression. (D) Quantification of T cells expressing granzyme B. For all presented studies, T cells were stimulated with CD3-CD28 dynabeads for 48 h prior to analyses. All described experiments were conducted at least three times with an n = 5/group. Figure S3. Molecular characterization of T cells. T cells sorted from ctl, PBS-treated, or IL-21-treated LP/J recipient mice were analyzed for their expression of various transcription factors involved in T cell differentiation. All described experiments were conducted at least three times with n = 5/group. Figure S4. Gating strategies for Breg analysis. For detection of IL-10-producing Bregs, CD19+ B cells were first isolated from spleens of treated mice (isotype shown by the filled gray histogram), then stained after in vitro treatment with CD1d and CD5 antibodies. The B cell subset CD1dhiCD5+ was gated prior to IL-10 assessment by intracellular staining. All described experiments were conducted at least three times with n = 5/group. (PDF 2111 kb

Engineering immunoproteasome-expressing mesenchymal stromal cells: A potent cellular vaccine for lymphoma and melanoma in mice

Dendritic cells (DCs) excel at cross-presenting antigens, but their effectiveness as cancer vaccine is limited. Here, we describe a vaccination approach using mesenchymal stromal cells (MSCs) engineered to express the immunoproteasome complex (MSC-IPr). Such modification instills efficient antigen cross-presentation abilities associated with enhanced major histocompatibility complex class I and CD80 expression, de novo production of interleukin-12, and higher chemokine secretion. This cross-presentation capacity of MSC-IPr is highly dependent on their metabolic activity. Compared with DCs, MSC-IPr hold the ability to cross-present a vastly different epitope repertoire, which translates into potent re-activation of T cell immunity against EL4 and A20 lymphomas and B16 melanoma tumors. Moreover, therapeutic vaccination of mice with pre-established tumors efficiently controls cancer growth, an effect further enhanced when combined with antibodies targeting PD-1, CTLA4, LAG3, or 4-1BB under both autologous and allogeneic settings. Therefore, MSC-IPr constitute a promising subset of non-hematopoietic antigen-presenting cells suitable for designing universal cell-based cancer vaccines