Impact of CMV Infection on Natural Killer Cell Clonal Repertoire in CMV-Naïve Rhesus Macaques

Abstract

Recent functional, gene expression, and epigenetic studies have suggested the presence of a subset of mature natural killer (NK) cells responsible for maintaining NK cell memory. The lack of endogenous clonal markers in NK cells impedes understanding the genesis of these cell populations. In humans, primates, and mice, this phenotype and memory or adaptive functions have been strongly linked to cytomegalovirus or related herpes virus infections. We have used transplantation of lentivirally-barcoded autologous hematopoietic stem and progenitor cells (HSPC) to track clonal hematopoiesis in rhesus macaques and previously reported striking oligoclonal expansions of NK-biased barcoded clones within the CD56−CD16+ NK cell subpopulation, clonally distinct from ongoing output of myeloid, B cell, T cell, and CD56+16− NK cells from HSPC. These CD56−CD16+ NK cell clones segregate by expression of specific KIR surface receptors, suggesting clonal expansion in reaction to specific environmental stimuli. We have now used this model to investigate the impact of rhesus CMV(RhCMV) infection on NK clonal dynamics. Following transplantation, RhCMVneg rhesus macaques display less dominant and oligoclonal CD16+ NK cells biased clones compared to RhCMVpos animals, however these populations of cells are still clearly present. Upon RhCMV infection, CD16+ NK cells proliferate, followed by appearance of new groups of expanded NK clones and disappearance of clones present prior to RhCMV infection. A second superinfection with RhCMV resulted in rapid viral clearance without major change in the mature NK cell clonal landscape. Our findings suggest that RhCMV is not the sole driver of clonal expansion and peripheral maintenance of mature NK cells; however, infection of macaques with this herpesvirus does result in selective expansion and persistence of specific NK cell clones, providing further information relevant to adaptive NK cells and the development of NK cell therapies.

Comparative engraftment and clonality of macaque HSPCs expanded on human umbilical vein endothelial cells versus non-expanded cells

“…Further, as reported for other barcoded animals, 20 , 31 both T cells and mature NK cells demonstrated a restricted set of expanded clones originating from both arms, likely resulting from peripheral expansions of mature T and NK cells potentially in response to viral reactivation or other environmental cues, as detailed in our prior macaque studies, and prior human gene therapy analyses. 31 , 32 , 33 , 34 , 35 Similar clonal patterns were also observed in the RN + cytokines arm in ZJ25 ( Figure S5 B). Direct comparisons using a combined heatmap of the expanded and non-expanded HSPC barcodes/clones ( Figure 2 B) showed that clonal distributions and clonal dynamics were similar in E-HUVEC and non-expanded arms in both animals.…”

Rhesus Macaque Activating Killer Immunoglobulin-Like Receptors Associate With Fc Receptor Gamma (FCER1G) and Not With DAP12 Adaptor Proteins Resulting in Stabilized Expression and Enabling Signal Transduction

“…FcRg-deficient adaptive NK cells were also reported in CMV-infected rhesus macaques (43). We hypothesize, that loss of FcRg in adaptive NK cells of macaques not only sharpens their CD16-mediated effector function as described previously by others (44), but that concomitant loss of activating KIRs further refines their immune function: moving towards antibody-driven and away from ligand (MHC class I)driven recognition. If this would indeed be the case, then macaque activating KIRs are expected to have a more prominent role in shaping adaptive NK cell functions as their human counterparts.…”

Clonal tracking of haematopoietic cells: insights and clinical implications

“…Expression of specific KIR cell surface receptors tracked with barcoded clones, linking clonal dynamics with expression of molecules known to be critical for response to viruses in the context of non‐classical MHC molecules such as human leucocyte antigen (HLA)‐E 115 . Following CMV infection of barcoded RMs, NK cell clonal patterns changed, supporting the concept of clonal adaptive NK responses 116 …”