Human Effector Memory T Helper Cells Engage with Mouse Macrophages and Cause Graft-versus-Host–Like Pathology in Skin of Humanized Mice Used in a Nonclinical Immunization Study

Abstract

Humanized mice engrafted with human hematopoietic stem cells and developing functional human T-cell adaptive responses are in critical demand to test human-specific therapeutics. We previously showed that humanized mice immunized with long-lived induced-dendritic cells loaded with the pp65 viral antigen (iDCpp65) exhibited a faster development and maturation of T cells. Herein, we evaluated these effects in a long-term (36 weeks) nonclinical model using two stem cell donors to assess efficacy and safety. Relative to baseline, iDCpp65 immunization boosted the output of effector memory CD4 T cells in peripheral blood and lymph nodes. No weight loss, human malignancies, or systemic graft-versus-host (GVH) disease were observed. However, for one reconstitution cohort, some mice immunized with iDCpp65 showed GVH-like signs on the skin. Histopathology analyses of the inflamed skin revealed intrafollicular and perifollicular human CD4 cells near F4/80 mouse macrophages around hair follicles. In spleen, CD4 cells formed large clusters surrounded by mouse macrophages. In plasma, high levels of human T helper 2-type inflammatory cytokines were detectable, which activated in vitro the STAT5 pathway of murine macrophages. Despite this inflammatory pattern, human CD8 T cells from mice with GVH reacted against the pp65 antigen in vitro. These results uncover a dynamic cross-species interaction between human memory T cells and mouse macrophages in the skin and lymphatic tissues of humanized mice.

In vivo generation of human CD 19‐ CAR T cells results in B‐cell depletion and signs of cytokine release syndrome

“…A surprising outcome of our study in fully humanized mice was the substantially increased concentrations of human cytokines in plasma of three of seven CAR‐positive animals concomitantly with B‐cell aplasia and the signs of neurotoxicity in one mouse. Human myeloid and CD4 + T cells are the likely source for the released cytokines (Tanaka et al , ; Sundarasetty et al , ). The cytokine profile resembled that of CAR T‐cell‐treated patients suffering from CRS (Hay et al , ).…”

Multidimensional Analysis Integrating Human T-Cell Signatures in Lymphatic Tissues with Sex of Humanized Mice for Prediction of Responses after Dendritic Cell Immunization

“…Prior to HSCT, mice were sublethally irradiated (450 cGy) using a [137 Cs ] column irradiator (Gammacell 3000 Elan; Best Theratronics, Ottawa, ON, Canada). 4 h after irradiation, 1.5–2.0 × 10 5 human CD34 + hematopoietic cells isolated from female donor umbilical CB were administrated to each mouse trough the tail vein as described ( 20 , 24 ). We had previously shown that immune reconstitution in female mice recipients was faster than in males ( 25 ) and we, therefore, used female donors to avoid any putative immune responses against antigens expressed in the Y chromosome of male recipients.…”

“…CD14 + monocytes were isolated at high purity (from the same CB units used as source of CD34 + HSCs) by immune-magnetic beads (Miltenyi Biotec, Bergisch Gladbach, Germany) and cryopreserved. CD14 + cells were used for the generation of iDCpp65 after transduction with a tricistronic integrase-defective lentiviral vector co-expressing human cytokines GM-CSF/IFN-α and the HCMV-pp65 protein as described (IDLV-G2a-pp65) ( 20 , 24 ). In short, monocytes were pre-conditioned with recombinant human GM-CSF and IL-4 (both 50 ng/ml; Cellgenix, Freiburg, Germany) for 8 h prior to lentiviral gene transfer.…”

“…We previously demonstrated that multiple administrations of iDCpp65 into NOD.Cg-Rag1 tm1Mom -Il2rγ tm1Wj (NRG) mice transplanted with human HSCs promoted a potent development of CD8 + antigen-specific memory responses in short (16 weeks) ( 20 ) and long (20–36 weeks) models ( 19 , 24 ). We have also demonstrated that another important factor to be considered regarding the analyses of human T cells in mice humanized with cord blood (CB)-HSCs is the gender of the recipient mouse.…”

Adult and Cord Blood-Derived High-Affinity gB-CAR-T Cells Effectively React Against Human Cytomegalovirus Infections

“…Mice were transplanted with CB-CD34 + cells using previously described techniques. [32][33][34][35] Briefly, human CD34 + cells were isolated after two rounds of positive selection with MACS magnetic beads (CD34 MicroBead Kit; Miltenyi Biotec). At the age of 4-6 weeks, mice were sublethally irradiated with 450 cGy using a 137 Cs-column irradiator (Gammacell 3000 Elan; Best Theratronics, Ottawa, Canada).…”