Protective function ofex vivoexpanded CD8 T cells in a mouse model of adoptive therapy for cytomegalovirus infection depends on integrin beta 1 but not CXCR3, CTLA4, or PD-1 expression

Abstract

AbstractThe adoptive transfer of virus-specific T cells (VSTs) represents a therapeutic option for viral infection treatment in immunocompromised patients. Before administration,ex vivoculture enables VST expansion. However, it is unclear howex vivoexpansion affects the circulation, homing, and intra-tissue migration of administered VSTs. We established a model of VST immunotherapy of acute cytomegalovirus infection using adoptive transfer ofex vivoexpanded OT-I CD8 T cells (recognizing SIINFEKL peptide) intoRag2-/-mice infected with murine cytomegalovirus (MCMV) encoding for the SIINFEKL peptide.Ex vivoexpansion induced an effector T cell phenotype and affected the expression of integrins and chemokine receptors. CRISPR/Cas9-mediated gene deletions enabled us to address the role of selected genes in the homing of VSTs following intravenous administration. We found that deletion ofItgb1, encoding for integrin beta 1, prevented OT-I cells from entering infected organs and drastically reduced their number in blood, suggesting that adoptively transferred VSTs primarily expand in the infected tissues. In contrast,Cxcr3-/-OT-I cells provided equal protection as theirCxcr3+/+counterparts, indicating that this chemokine receptor does not contribute to VST entry into infected organs. Further,Pdcd1andCtla4deletion did not impair the transferred OT-I cells’ ability to protect mice from MCMV, arguing against quick exhaustion of VSTs with an effector T cell phenotype. Together, these data indicate thatex vivoexpansion affects migration and activation properties of VSTs and suggest that future clinical evaluation of adoptive T cell therapy efficacy should include homing molecule expression assessment.