Soluble factors released by peripheral blood-derived CAR-NK cells cause bystander myeloid cell activation.

Introduction: CAR-T cell therapy is associated with life-threatening inflammatory toxicities, partly due to the activation and secretion of inflammatory cytokines by bystander myeloid cells (BMCs). However, due to limited clinical data, it is unclear whether CAR-NK cells cause similar toxicities.

Methods: We characterized the soluble factors (SFs) released by activated human CAR-T and CAR-NK cells and assessed their role in BMC activation (BMCA).

TCR-independent Activation in Presence of a Src-family Kinase Inhibitor Improves CAR-T Cell Product Attributes.

Chimeric antigen receptor expressing T cells (CAR-T cells) have shown remarkable efficacy against some blood cancers and have potential to treat many other human diseases. During CAR-T cell manufacturing, T cells are activated via engagement of the T-cell receptor (TCR); however, persistent TCR engagement can induce unchecked activation, differentiation, and exhaustion, which can negatively affect CAR-T cell product quality and in vivo potency. In addition, T cells may not uniformly respond to TCR-dependent activation (TCRD) contributing to lot-to-lot variability, poor expansion, and manufacturing failures.

A short hepatitis C virus NS5A peptide expression by AAV vector modulates human T cell activation and reduces vector immunogenicity.

Viral vector-mediated gene therapies have the potential to treat many human diseases; however, host immune responses against the vector and/or the transgene pose a safety risk to the patients and can negatively impact product efficacy. Thus, novel strategies to reduce vector immunogenicity are critical for the advancement of these therapies. T cell activation (TCA) is required for the development of immune responses during gene therapy.

Characterization of the effects of immunomodulatory drug fingolimod (FTY720) on human T cell receptor signaling pathways.

Immune responses against gene therapy products limit its therapeutic efficacy and present a safety risk. Identification of agents that blunt immune reactions may aid in developing novel immunomodulatory therapies. Fingolimod (FTY720) is an FDA approved immunomodulatory drug for treating multiple sclerosis that inhibits lymphocyte egress from lymphoid tissues by down regulating sphingosine-1 phosphate receptor (S1PR).

Src-family kinases negatively regulate NFAT signaling in resting human T cells.

T cell signaling is required for activation of both natural and therapeutic T cells including chimeric antigen receptor (CAR) T cells. Identification of novel factors and pathways regulating T cell signaling may aid in development of effective T cell therapies. In resting human T cells, the majority of Src-family of tyrosine kinases (SFKs) are inactive due to phosphorylation of a conserved carboxy-terminal tyrosine residue.

Three cysteine residues of SLC52A1, a receptor for the porcine endogenous retrovirus-A (PERV-A), play a critical role in cell surface expression and infectivity.

Porcine endogenous retrovirus-A (PERV-A), a gammaretrovirus, infects human cells in vitro, thus raising the potential risk of cross-species transmission in xenotransplantation. Two members of the solute carrier family 52 (SLC52A1 and SLC52A2) are PERV-A receptors. Site-directed mutagenesis of the cDNA encoding SLC52A1 identified that only one of two putative glycosylation signals is occupied by glycans.

Susceptibility of porcine endogenous retrovirus to anti-retroviral inhibitors.

Background: Porcine endogenous retrovirus (PERV) is an endogenous retrovirus that poses a risk of iatrogenic transmission in the context of pig-to-human xenotransplantation. The lack of a means to control PERV infection in the context of pig-to-human xenotransplantation is a major concern in the field. In this study, we set out to evaluate the ability of currently licensed anti-HIV drugs, and other types of anti-retroviral compounds, to inhibit PERV infection in vitro.

Limited infection without evidence of replication by porcine endogenous retrovirus in guinea pigs.

Porcine endogenous retrovirus (PERV) may potentially be transmitted through porcine xenotransplantation products administered to humans. This study examined the feasibility of using guinea pigs as a model to characterize the in vivo infectivity of PERV. To enhance the susceptibility of guinea pigs to retroviral infection or genomic integration, moderate physiological or immunological changes were induced prior to exposing the animals to PERV.

Sequence analysis of porcine endogenous retrovirus long terminal repeats and identification of transcriptional regulatory regions.

Porcine cells express endogenous retroviruses, some of which are infectious for human cells. To better understand the replication of these porcine endogenous retroviruses (PERVs) in cells of different types and animal species, we have performed studies of the long terminal repeat (LTR) region of known gammaretroviral isolates of PERV. Nucleotide sequence determination of the LTRs of PERV-NIH, PERV-C, PERV-A, and PERV-B revealed that the PERV-A and PERV-B LTRs are identical, whereas the PERV-NIH and PERV-C LTRs have significant sequence differences in the U3 region between each other and with the LTRs of PERV-A and PERV-B.