Omicron-Specific Cytotoxic T-Cell Responses After a Third Dose of mRNA COVID-19 Vaccine Among Patients With Multiple Sclerosis Treated With Ocrelizumab.

Importance: The SARS-CoV-2 variant B.1.1.

Robust T-Cell Responses in Anti-CD20-Treated Patients Following COVID-19 Vaccination: A Prospective Cohort Study.

Background: Patients treated with anti-CD20 therapy are particularly at risk of developing severe coronavirus disease 2019 (COVID-19); however, little is known regarding COVID-19 vaccine effectiveness in this population.

Methods: This prospective observational cohort study assesses humoral and T-cell responses after vaccination with 2 doses of mRNA-based COVID-19 vaccines in patients treated with rituximab for rheumatic diseases or ocrelizumab for multiple sclerosis (n = 37), compared to immunocompetent individuals (n = 22).

Results: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibodies were detectable in only 69.

Prolongation of rat-to-mouse islets xenograft survival by co-transplantation of autologous IL-10 differentiated murine tolerogenic dendritic cells.

Background: Tolerogenic dendritic cells (DCs) represent a promising approach to promote transplantation tolerance. In this study, the potential of autologous bone marrow (BM)-derived murine DC to protect rat-to-mouse islets xenografts was analyzed.

Methods: Tolerogenic DCs were generated by differentiating BM cells in the presence of granulocyte-macrophage colony-stimulating factor and interleukin 10 (IL-10, IL-10 DC).

Macroautophagy in Dendritic Cells Controls the Homeostasis and Stability of Regulatory T Cells.

Regulatory T cells (Tregs) play a crucial role in controlling autoimmune and inflammatory responses. Recent studies have demonstrated that dendritic cells (DCs) contribute to the homeostasis of peripheral Tregs. Autophagy, a critical pathway for cellular homeostasis, is active in DCs and is upregulated in different inflammatory conditions.

Absence of MHC-II expression by lymph node stromal cells results in autoimmunity.

How lymph node stromal cells (LNSCs) shape peripheral T-cell responses remains unclear. We have previously demonstrated that murine LNSCs, lymphatic endothelial cells (LECs), blood endothelial cells (BECs), and fibroblastic reticular cells (FRCs) use the IFN-γ-inducible promoter IV (pIV) of the MHC class II (MHCII) transactivator CIITA to express MHCII. Here, we show that aging mice (>1 yr old) in which MHCII is abrogated in LNSCs by the selective deletion of pIV exhibit a significant T-cell dysregulation in LNs, including defective Treg and increased effector CD4 and CD8 T-cell frequencies, resulting in enhanced peripheral organ T-cell infiltration and autoantibody production.

Release of pig leukocytes and reduced human NK cell recruitment during ex vivo perfusion of HLA-E/human CD46 double-transgenic pig limbs with human blood.

Background: In pig-to-human xenotransplantation, interactions between human natural killer (NK) cells and porcine endothelial cells (pEC) are characterized by recruitment and cytotoxicity. Protection from xenogeneic NK cytotoxicity can be achieved in vitro by the expression of the non-classical human leukocyte antigen-E (HLA-E) on pEC. Thus, the aim of this study was to analyze NK cell responses to vascularized xenografts using an ex vivo perfusion system of pig limbs with human blood.

Human anti-pig NK cell and CD8 T-cell responses in the presence of regulatory dendritic cells.

Background: Dendritic cells (DC) play a major role in natural killer (NK) cell and cytotoxic T lymphocyte (CTL) activation leading to cell-mediated xenogeneic responses. In contrast, the use of in vitro differentiated regulatory DC may represent an attractive approach to protect porcine endothelial cells (pEC) from human cell-mediated immune responses. In this study, we evaluated the potential of human regulatory DC to reduce xenogeneic NK cell and CTL responses to pEC.

Chemoattractant Signals and Adhesion Molecules Promoting Human Regulatory T Cell Recruitment to Porcine Endothelium.

Background: Human CD4+CD25+Foxp3+ T regulatory cells (huTreg) suppress CD4+ T cell-mediated antipig xenogeneic responses in vitro and might therefore be used to induce xenograft tolerance. The present study investigated the role of the adhesion molecules, their porcine ligands, and the chemoattractant factors that may promote the recruitment of huTreg to porcine aortic endothelial cells (PAEC) and their capacity to regulate antiporcine natural killer (NK) cell responses.

Methods: Interactions between ex vivo expanded huTreg and PAEC were studied by static chemotaxis assays and flow-based adhesion and transmigration assays.