Tomotherapy Applied Total Lymphoid Irradiation and Allogeneic Hematopoietic Cell Transplantation Generates Mixed Chimerism in the Rhesus Macaque Model

Early allogeneic immune modulation after establishment of donor hematopoietic cell-induced mixed chimerism in a nonhuman primate kidney transplant model

Background

Mixed lymphohematopoietic chimerism is a proven strategy for achieving operational transplant tolerance, though the underlying immunologic mechanisms are incompletely understood.

Methods

A post-transplant, non-myeloablative, tomotherapy-based total lymphoid (TLI) irradiation protocol combined with anti-thymocyte globulin and T cell co-stimulatory blockade (belatacept) induction was applied to a 3-5 MHC antigen mismatched rhesus macaque kidney and hematopoietic cell transplant model. Mechanistic investigations of early (60 days post-transplant) allogeneic immune modulation induced by mixed chimerism were conducted.

Results

Chimeric animals demonstrated expansion of circulating and graft-infiltrating CD4+CD25+Foxp3+ regulatory T cells (Tregs), as well as increased differentiation of allo-protective CD8+ T cell phenotypes compared to naïve and non-chimeric animals. In vitro mixed lymphocyte reaction (MLR) responses and donor-specific antibody production were suppressed in animals with mixed chimerism. PD-1 upregulation was observed among CD8+ T effector memory (CD28-CD95+) subsets in chimeric hosts only. PD-1 blockade in donor-specific functional assays augmented MLR and cytotoxic responses and was associated with increased intracellular granzyme B and extracellular IFN-γ production.

Conclusions

These studies demonstrated that donor immune cell engraftment was associated with early immunomodulation via mechanisms of homeostatic expansion of Tregs and early PD-1 upregulation among CD8+ T effector memory cells. These responses may contribute to TLI-based mixed chimerism-induced allogenic tolerance.

Efficacy and safety of epigallocatechin-3-gallate in treatment acute severe dermatitis in patients with cancer receiving radiotherapy: a phase I clinical trial

To evaluate the safety and effectiveness of epigallocatechin-3-gallate (EGCG) solution treating the acute severe dermatitis in patients receiving radiotherapy. This phase I research enrolled patients with thoracic cancer receiving radiotherapy at Shandong Cancer Hospital and Institute in Shandong, China. EGCG solution was sprayed to the radiation field when grade III radiation-induced dermatitis (RID) first appearance. EGCG concentration escalated from 660 to 2574 μmol/L using modified-Fibonacci dose-escalation. RID and related symptoms were followed up every day. Between March 2021 and November 2021, 19 patients were enrolled in this phase I research. The median dose of grade III RID first observation was 44 Gy (30.6-52 Gy). As the EGCG treatment was performed continuously, all these grade III RID reactions were significantly decreased to grade I or grade II RID at three days after use of EGCG (p < 0.001). Significant relief can be observed in burning sensation (p < 0.001), tractive sensation (p < 0.001), tenderness (p < 0.001), erythema (p < 0.001), itching (p < 0.001) and pain (p < 0.001) after 15 days of EGCG treatment. No radiation therapy delay or interruption for all 19 patients. No adverse events were observed and reported associated with EGCG. The highest dose of this Phase I trial (2574 μmol/L) was recommended for continuous Phase II trial for further evaluation. In this phase I clinical research, use of EGCG solution is safe and can significantly relief grade III RID in patients receiving radiotherapy. Thus, EGCG might be a new choice for acute sever RID.Trial Registration: ClinicalTrials.gov Identifier: NCT02580279 (Full date of first registration: 12/2014).

Helical TomoTherapy Total Lymphoid Irradiation and Hematopoietic Cell Transplantation for Kidney Transplant Tolerance in Rhesus Macaques

Development of a post-transplant kidney transplant tolerance induction protocol involving a novel total lymphoid irradiation (TLI) conditioning method in a rhesus macaque model is described. We examined the feasibility of acheiving tolerance to MHC 1-haplotype matched kidney transplants by establishing a mixed chimeric state with infusion of donor hematopoietic cells (HC) using TomoTherapy TLI. The chimeric state was hypothesized to permit the elimination of all immunosuppressive (IS) medications while preserving allograft function long-term without development of graft-versus-host-disease (GVHD) or rejection. An experimental group of 11 renal transplant recipients received the tolerance induction protocol and outcomes were compared to a control group (n = 7) that received the same conditioning but without donor HC infusion. Development of mixed chimerism and operational tolerance was accomplished in two recipients in the experimental group. Both recipients were withdrawn from all IS and continued to maintain normal renal allograft function for 4 years without rejection or GVHD. None of the animals in the control group achieved tolerance when IS was eliminated. This novel experimental model demonstrated the feasibility for inducing of long-term operational tolerance when mixed chimerism is achieved using a TLI post-transplant conditioning protocol in 1-haplotype matched non-human primate recipients of combined kidney and HC transplantation.

MHC Class I Ligands of Rhesus Macaque Killer Cell Ig-like Receptors

Definition of MHC class I ligands of rhesus macaque killer cell Ig-like receptors (KIRs) is fundamental to NK cell biology in this species as an animal model for infectious diseases, reproductive biology, and transplantation. To provide a more complete foundation for studying NK cell responses, rhesus macaque KIRs representing common allotypes of lineage II KIR genes were tested for interactions with MHC class I molecules representing diverse Macaca mulatta (Mamu)-A, -B, -E, -F, -I, and -AG alleles. KIR-MHC class I interactions were identified by coincubating reporter cell lines bearing chimeric KIR-CD3ζ receptors with target cells expressing individual MHC class I molecules and were corroborated by staining with KIR IgG-Fc fusion proteins. Ligands for 12 KIRs of previously unknown specificity were identified that fell into three general categories: interactions with multiple Mamu-Bw4 molecules, interactions with Mamu-A-related molecules, including allotypes of Mamu-AG and the hybrid Mamu-B*045:03 molecule, or interactions with Mamu-A1*012:01. Whereas most KIRs found to interact with Mamu-Bw4 are inhibitory, most of the KIRs that interact with Mamu-AG are activating. The KIRs that recognize Mamu-A1*012:01 belong to a phylogenetically distinct group of macaque KIRs with a 3-aa deletion in the D0 domain that is also present in human KIR3DL1/S1 and KIR3DL2. This study more than doubles the number of rhesus macaque KIRs with defined MHC class I ligands and identifies interactions with Mamu-AG, -B*045, and -A1*012. These findings support overlapping, but nonredundant, patterns of ligand recognition that reflect extensive functional diversification of these receptors.

KIR3DL05 and KIR3DS02 Recognition of a Nonclassical MHC Class I Molecule in the Rhesus Macaque Implicated in Pregnancy Success

Knowledge of the MHC class I ligands of rhesus macaque killer-cell Ig-like receptors (KIRs) is fundamental to understanding the role of natural killer (NK) cells in this species as a nonhuman primate model for infectious diseases, transplantation and reproductive biology. We previously identified Mamu-AG as a ligand for KIR3DL05. Mamu-AG is a nonclassical MHC class I molecule that is expressed at the maternal-fetal interface of the placenta in rhesus macaques similar to HLA-G in humans. Although Mamu-AG and HLA-G share similar molecular features, including limited polymorphism and a short cytoplasmic tail, Mamu-AG is considerably more polymorphic. To determine which allotypes of Mamu-AG serve as ligands for KIR3DL05, we tested reporter cell lines expressing five different alleles of KIR3DL05 (KIR3DL05*001, KIR3DL05*004, KIR3DL05*005, KIR3DL05*008 and KIR3DL05*X) for responses to target cells expressing eight different alleles of Mamu-AG. All five allotypes of KIR3DL05 responded to Mamu-AG2*01:01, two exhibited dominant responses to Mamu-AG1*05:01, and three had low but detectable responses to Mamu-AG3*03:01, -AG3*03:02, -AG3*03:03 and -AG3*03:04. Since KIR3DL05*X is the product of recombination between KIR3DL05 and KIR3DS02, we also tested an allotype of KIR3DS02 (KIR3DS02*004) and found that this activating KIR also recognizes Mamu-AG2*01:01. Additional analysis of Mamu-AG variants with single amino acid substitutions identified residues in the α1-domain essential for recognition by KIR3DL05. These results reveal variation in KIR3DL05 and KIR3DS02 responses to Mamu-AG and define Mamu-AG polymorphisms that differentially affect KIR recognition.