Genetic Modification of Tumor-Infiltrating Lymphocytes, Peripheral T Cells, and T-Cell Model Cell Lines.

Genetic modification of tumor-infiltrating lymphocytes (TILs) or circulating T cells has become an important avenue in cancer therapy. Here we describe a comprehensive method for establishing and expanding TIL cultures and genetically modifying them with a gene of interest (GOI) via retroviral transduction or mRNA transfection. The method includes all the important steps starting with TIL extraction from tumors through to the maintenance of the genetically modified TILs. The protocol includes instructions for retroviral transduction and mRNA transfection of circulating T cells or T-cell lines. The GOIs most commonly introduced into the target cells are chimeric antigen receptors (CARs); genetic adjuvants, such as membrane-bound interleukins; and antitumor T-cell receptors (TCRs).

Modeling SARS-CoV-2 Infection in Mice Using Lentiviral hACE2 Vectors Infers Two Modes of Immune Responses to SARS-CoV-2 Infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a severe global pandemic. Mice models are essential to investigate infection pathology, antiviral drugs, and vaccine development. However, wild-type mice lack the human angiotensin-converting enzyme 2 (hACE2) that mediates SARS-CoV-2 entry into human cells and consequently are not susceptible to SARS-CoV-2 infection. hACE2 transgenic mice could provide an efficient COVID-19 model, but are not always readily available, and practically restricted to specific strains. Therefore, there is a dearth of additional mouse models for SARS-CoV-2 infection. We applied lentiviral vectors to generate hACE2 expression in interferon receptor knock-out (IFNAR1-/-) mice. Lenti-hACE2 transduction supported SARS-CoV-2 replication in vivo, simulating mild acute lung disease. Gene expression analysis revealed two modes of immune responses to SARS-CoV-2 infection: one in response to the exposure of mouse lungs to SARS-CoV-2 particles in the absence of productive viral replication, and the second in response to productive SARS-CoV-2 infection. Our results infer that immune response to immunogenic elements on incoming virus or in productively infected cells stimulate diverse immune effectors, even in absence of type I IFN signaling. Our findings should contribute to a better understanding of the immune response triggered by SARS-CoV-2 and to further elucidate COVID-19.