癌症生物学

Chimeric antigen receptors (CARs) are synthetic fusion proteins that can reprogram immune cells to target specific antigens. CAR-expressing T cells have emerged as an effective treatment method for hematological cancers; despite this success, the mechanisms and structural properties that govern CAR responses are not fully understood. Here, we provide a simple assay to assess cellular avidity using a standard flow cytometer. This assay measures the interaction kinetics of CAR-expressing T cells and targets antigen-expressing target cells. By co-culturing stably transfected CAR Jurkat cells with target positive and negative cells for short periods of time in a varying effector–target gradient, we were able to observe the formation of CAR-target cell doublets, providing a readout of actively bound cells. When using the optimized protocol reported here, we observed unique cellular binding curves that varied between CAR constructs with differing antigen binding domains. The cellular binding kinetics of unique CARs remained consistent, were dependent on specific target antigen expression, and required active biological signaling. While existing literature is not clear at this time whether higher or lower CAR cell binding is beneficial to CAR therapeutic activity, the application of this simplified protocol for assessing CAR binding could lead to a better understanding of the proximal signaling events that regulate CAR functionality.

Genome-editing technologies, especially CRISPR (clustered regularly interspaced short palindrome repeats)/Cas9 (CRISPR-associated protein 9), endows researchers the ability to make efficient, simple, and precise genomic DNA changes in many eukaryotic cell types. CRISPR/Cas9-mediated efficient gene knockout holds huge potential to improve the efficacy and safety of chimeric antigen receptor (CAR) T cell-based immunotherapies. Here, we describe an optimized approach for a complete loss of endogenous T cell receptor (TCR) protein expression, by CRISPR/Cas9-mediated TCR α constant (TRAC) and TCR β constant (TRBC) gene knockout, followed by subsequent CD3 negative selection in engineered human orthoCAR19 T cells. We believe this method can be expanded beyond CAR T cell application, and target other cell surface receptors.

Graphical abstract:

Schematic overview of the two-step process of endogenous TCR depletion in engineered human orthoCAR19 T cells using (1) CRISPR/Cas9-mediated gene knockout followed by (2) CD3 negative selection.

Intranasal administration of vaccine adjuvants directly deliver therapeutic agents to the lungs to induce potent lung mucosal immune responses. Cyclic di-GMP (CDG) is a promising mucosal vaccine adjuvant candidate capable of inducing protective immunity. This protocol describes an in vivo approach to induce and detect mucosal (lung) and systemic (blood and spleen) vaccine adjuvant responses of CDG. This protocol also includes the methods to detect both humoral and cellular immune responses of CDG adjuvant. Last, this protocol can be used to study other cyclic dinucleotides as mucosal vaccine adjuvants.

Many therapeutic viruses, such as oncolytic viruses, vaccines, or gene therapy vectors, may be administered by the intravenous route to maximize their delivery to target tissues. Blood components, such as antibody, complement and blood cells (such as neutrophils, monocytes, T cells, B cells or platelets) may result in viral neutralization and therefore reduce the therapeutic efficacy. This protocol will describe an in vitro assay by which to test the interaction of viruses with blood components. The effect of various factors can be isolated through fractionation. While whole blood can offer the most physiologically relevant snapshot, plasma can investigate the effects of antibody in concert with complement, and heat inactivated plasma will interrogate the effect of antibody alone.

Macrophages are involved in many key physiological processes and complex responses such as inflammatory, immunological, infectious and neoplastic diseases. The appearance and activation of macrophages are thought to be rapid events in the development of many pathological lesions, including malignant tumours, atherosclerotic plaques, and arthritic joints. This has prompted recent attempts to use macrophages as novel cellular vehicles for gene therapy, in which macrophages are genetically modified ex vivo and then reintroduced into the body with the hope that a proportion will then home to the diseased site. Here, we describe a protocol for preparing monocyte-derived macrophages (MDM) and arming these with oncolytic viruses (OV) as a novel way for delivering anti-cancer therapies. In this approach, proliferation of macrophages co-transduced with a hypoxia-regulated E1A/B construct and an E1A-dependent oncolytic adenovirus, is restricted to prostate tumour cells using prostate-specific promoter elements from the TARP, PSA, and PMSA genes (Muthana et al., 2013; Muthana et al., 2011). When such co-transduced cells reach an area of extreme hypoxia (like that found in tumours), the E1A/B proteins are expressed, thereby activating replication of the adenovirus. The virus is subsequently released by the host macrophage and infects neighboring tumour cells. The virus then infects neighboring cells but only proliferates and is cytotoxic in prostate tumour cells. OV kill cancer cells by a number of mechanisms, including direct lysis, apoptosis, autophagy and shutdown of protein synthesis, as well as the induction of anti-tumoural immunity. Using macrophages to deliver OV ensures that they are protected from the many hazards they face in circulation including neutralizing antibodies, complement activation and non-specific uptake by other tissues such as the liver and spleen.