Preferential Small Intestine Homing and Persistence of CD8 T Cells in Rhesus Macaques Achieved by Molecularly Engineered Expression of CCR9 and ReducedEx VivoManipulation

Abstract

Adoptive cell transfer (ACT) is a powerful experimental approach to directly study T-cell-mediated immunity in vivo. In the rhesus macaque AIDS virus model, infusing simian immunodeficiency virus (SIV)-infected animals with CD8 T cells engineered to express anti-SIV T-cell receptor specificities enables direct experimentation to better understand antiviral T-cell immunity in vivo. Limiting factors in ACT experiments include suboptimal trafficking to, and poor persistence in, the secondary lymphoid tissues targeted by AIDS viruses. Previously, we redirected CD8 T cells to B-cell follicles by ectopic expression of the CXCR5 homing protein. Here, we modify peripheral blood mononuclear cell (PBMC)-derived CD8 T cells to express the CCR9 chemokine receptor, which induces preferential homing of the engineered cells to the small intestine, a site of intense early AIDS virus replication and pathology in rhesus macaques. Additionally, we increase in vivo persistence and overall systemic distribution of infused CD8 T cells, especially in secondary lymphoid tissues, by minimizing ex vivo culture/manipulation, thereby avoiding the loss of CD28+/CD95+ central memory T cells by differentiation in culture. These proof-of-principle results establish the feasibility of preferentially localizing PBMC-derived CD8 T cells to the small intestine and enables the direct experimental ACT-based assessment of the potential role of the quality and timing of effective antiviral CD8 T-cell responses to inhibit viral infection and subsequent replication in small intestine CD4 T cells. More broadly, these results support the engineered expression of homing proteins to direct CD8 T cells to target tissues as a means for both experimental and potential therapeutic advances in T-cell immunotherapies, including cancer. IMPORTANCE Adoptive cell transfer (ACT) of T cells engineered with antigen-specific effector properties can deliver targeted immune responses against malignancies and infectious diseases. Current T-cell-based therapeutic ACT relies on circulatory distribution to deliver engineered T cells to their targets, an approach which has proven effective for some leukemias but provided only limited efficacy against solid tumors. Here, engineered expression of the CCR9 homing receptor redirected CD8 T cells to the small intestine in rhesus macaque ACT experiments. Targeted homing of engineered T-cell immunotherapies holds promise to increase the effectiveness of adoptively transferred cells in both experimental and clinical settings.

Efficient ex vivo expansion of conserved element vaccine-specific CD8+ T-cells from SHIV-infected, ART-suppressed nonhuman primates

“…To evaluate the safety and “vein-to-vein” performance of ex vivo expanded, vaccine-induced CE-specific T-cell products, we investigated their frequency and biodistribution in vivo following autologous infusion, and their ability to protect against intrarectal (IR) SHIV challenge. To specifically track adoptively transferred NHP CE-XTC products and their proliferation in vivo , cells were labeled with carboxyfluorescein succinimidyl ester (CFSE) on day 19 of the expansion period, a strategy that is analogous to previous methods ( 30 , 31 ). The labeled products were then infused into the two CE-vaccinated, uninfected animals, prioritizing a maximum cell dose based on each product’s expansion rather than a standardized cell dose per kilogram body weight.…”

Targeting Immune Cell Trafficking – Insights From Research Models and Implications for Future IBD Therapy

“…This interaction leads to activation, proliferation and imprinting of T cells with a gut homing phenotype through upregulation of specific adhesion molecules. T cells imprinted for small intestinal homing express integrin a4b7, a4b1, b2 integrins and CCR9, while cells primed for migration to the colon show high levels of integrin a4b7 and GPR15 (5)(6)(7)(8). Upon recirculation, these T cell subsets may subsequently migrate to the gut as their target tissue along chemotactic gradients, where they interact with the molecules expressed by endothelial cells to initiate the multistep extravasation process of gut homing.…”

Epithelial injury in acute graft-versus-host disease of the gut

“…The mere stimulation or inhibition on the systemic level therefore may not result in the intended outcome. New ways to specifically target the intestine, for example through intestinedirected genetically engineered cells 210 or carriers such as nanoparticles 211,212,213 , might make additional GI-targeted approaches more feasible in the future, similar to the wide use of oral budesonide for more targeted administration of corticosteroids to the GI tract. On an even smaller scale, a better understanding of the structural design of factors involved may enable the decoupling of protective functions from pro-inflammatory effects.…”