Constitutive activation of WASp leads to abnormal cytotoxic cells with increased granzyme B and degranulation response to target cells
Joanna S. Kritikou, … , Jordan S. Orange, Lisa S. Westerberg
Joanna S. Kritikou, … , Jordan S. Orange, Lisa S. Westerberg
Published February 23, 2021
Citation Information: JCI Insight. 2021;6(6):e140273. https://doi.org/10.1172/jci.insight.140273.
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Research Article Immunology

Constitutive activation of WASp leads to abnormal cytotoxic cells with increased granzyme B and degranulation response to target cells

Abstract

X-linked neutropenia (XLN) is caused by gain-of-function mutations in the actin regulator Wiskott-Aldrich Syndrome protein (WASp). XLN patients have reduced numbers of cytotoxic cells in peripheral blood; however, their capacity to kill tumor cells remains to be determined. Here, we examined NK and T cells from 2 patients with XLN harboring the activating WASpL270P mutation. XLN patient NK and T cells had increased granzyme B content and elevated degranulation and IFN-γ production when compared with healthy control cells. Murine WASpL272P NK and T cells formed stable synapses with YAC-1 tumor cells and anti-CD3/CD28–coated beads, respectively. WASpL272P mouse T cells had normal degranulation and cytokine response whereas WASpL272P NK cells showed an enhanced response. Imaging experiments revealed that while WASpL272P CD8+ T cells had increased accumulation of actin upon TCR activation, WASpL272P NK cells had normal actin accumulation at lytic synapses triggered through NKp46 signaling but had impaired response to lymphocyte function associated antigen-1 engagement. When compared with WT mice, WASpL272P mice showed reduced growth of B16 melanoma and increased capacity to reject MHC class I–deficient cells. Together, our data suggest that cytotoxic cells with constitutively active WASp have an increased capacity to respond to and kill tumor cells.

Authors

Joanna S. Kritikou, Mariana M.S. Oliveira, Julien Record, Mezida B. Saeed, Saket M. Nigam, Minghui He, Marton Keszei, Arnika K. Wagner, Hanna Brauner, Anton Sendel, Saikiran K. Sedimbi, Stamatina Rentouli, David P. Lane, Scott B. Snapper, Klas Kärre, Peter Vandenberghe, Jordan S. Orange, Lisa S. Westerberg

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Figure 2

NK and T cells from XLN patients are more responsive to stimulation.

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NK and T cells from XLN patients are more responsive to stimulation. (A)...
(A) Degranulation, as measured by CD107a surface expression, and IFN-γ production in healthy control and XLN patient NK cells. Representative flow cytometry plots are shown on the left and quantification of NK cell responses against K562 tumor cells and PMA/Ionomycin on the right. CD107a+IFN-γ+ NK cells include CD107a single positive (SP), IFN-γ SP, and CD107a IFN-γ double-positive (DP) cells. The average of nonresponding and CD107a/IFN-γ–responding NK cells after PMA/ionomycin stimulation is shown as pie charts in healthy controls and XLN patients. (B) Degranulation and IFN-γ production in healthy control and XLN patient CD4+ and CD8+ T cells. Representative flow cytometry plots are shown on the left and quantification of T cell responses to PMA/ionomycin stimulation on the right. CD107a+IFN-γ+ T cells include CD107a SP, IFN-γ SP, and CD107a IFN-γ DP cells. The average of nonresponding and CD107a/IFN-γ–responding CD8+ T cells after PMA/ionomycin stimulation is shown as pie charts in healthy controls and XLN patients. One representative experiment of 2 is shown, with 2 samples for the healthy and XLN groups and 1 sample for the mother/sister control group. Graphs show mean values ± SEM and significance was assessed by 2-tailed Student’s t test between the healthy control and XLN patient groups. *P ≤ 0.05, **P ≤ 0.01. If no other indication, results were not significant.