RESUMO
Natural killer (NK) cells are large granular lymphocytes that keep in check the health of neighboring cells through a large array of intrinsically expressed germline-coded receptors. Most importantly, CD16 is a low affinity Fc receptor for IgG that mediates the antibody-dependent cellular cytotoxicity (ADCC) of NK cells, bridging the innate and adaptive immunities. There has been a significant interest in genetically engineering NK cells to enhance its ADCC, with the ultimate goal to produce off-the-shelf NK cell therapy products that can be combined with target-specific monoclonal antibodies to improve clinical outcomes. Previous protocols of ADCC assays use complex cell-based antigen-antibody models, which are both costly and time-consuming. This current protocol is devoid of target cells and uses plate-bound immobilized anti-CD16 antibodies as the trigger. It greatly shortens the experimental time, while faithfully evaluating NK cells ADCC. Graphic abstract: Workflow of stimulating NK cells via CD16 by plate-bound anti-CD16 mAb.
RESUMO
Functional and mechanistic studies of CD4+ T cell lineages rely on robust methods of in vitro T cell polarization. Here, we report an optimized protocol for in vitro differentiation of a mouse non-pathogenic T helper 17 (TH17) cell lineage. Most of the previously established protocols require irradiated splenocytes as artificial antigen presenting cells (APC) for TCR activation. The protocol described here employs plate-bound antibodies and a TH17-polarizing cytokine cocktail to activate and differentiate naïve CD4+ T (Tnai) cells, reflecting a simple and robust protocol for in vitro TH17n differentiation. Using T cells that are genetically engineered with an IL-17 reporter, this protocol may enable the rapid production of a pure population of IL17-expressing CD4+ T cells for system biology studies and high-throughput functional screening.
RESUMO
Mucosal-associated invariant T (MAIT) cells are an abundant innate-like T cell subset in humans, enriched in mucosal tissues and the liver. MAIT cells express a semi-invariant T cell receptor (TCR) and recognize microbial-derived riboflavin metabolites presented on the MHC Class I-like molecule MR1. In addition to activation via the TCR, MAIT cells can also be activated in response to cytokines such as IL-12 and IL-18, in contrast to conventional T cells. Here we describe TCR-dependent and -independent methods for MAIT cell activation. The TCR-dependent approaches include stimulation with microbead- or plate-bound anti-CD3/anti-CD28 antibodies, and with 5-OP-RU or paraformaldehyde (PFA)-fixed E. coli in the presence of antigen-presenting cells (APCs). The latter method includes a combination of TCR- and cytokine-mediated stimulation. The TCR-independent methods include direct stimulation with the recombinant cytokines IL-12 and IL-18, and indirect stimulation with TLR-4/TLR-8 agonists or influenza A virus in the presence of APCs. Finally, we outline a protocol to analyze activated MAIT cells using flow cytometry.