Table 4.

Leukocyte sources for tissue models.

Leukocyte	Cell Source	Main Challenges	Tissue Chip Models with TEM
Neutrophil/PMN	Blood isolation	• Biological variability • Supply constraints	• (62) • (80) • (65) • (66) • (32) • (67) • (34)
	Cryopreserved purified human PMNs	• Reduced chemotactic and polarization capability	• None
	HL-60 differentiation: Martin et al., 1990	• Diminished effector functions	• (227)
	hiPSC: Brok-Volchanskaya et al., 2019	• Decreased chemotactic response • Contains a population of immature cells lacking phagocytic activity	• None
Monocytes	Blood isolation	• Biological variability • Supply constraints	• (228) • (229)
	Immortalized monocyte-like cell lines (e.g., THP-1, U-937)	• Differing phenotypic effects and functional measures, including TEM	• (50) • (44) • (228) • (229)
	hiPSC: Yanagimachi et al., 2013; Takata et al., 2017; Cao et al., 2019; Cui et al., 2021	• Not fully characterized	• (230)
T Cells	Blood isolation	• Biological variability • Supply constraints	• (231)
	Immortalized Jurkat T cells	• Distinct actin organization and dynamics • Lack negative regulators of TCR signaling • Impaired ability to receive costimulatory signals • Large subset of differentially expressed genes	• (232)
	hiPSC: Nishimura et al., 2013; Themeli et al., 2013; Vizcardo et al., 2013; Ando et al., 2015; Maeda et al., 2016	• Optimized for cell-based immunotherapy applications only	• None

TEM, transmigration; PMN, polymorphonuclear leukocytes; hiPSC, human induced pluripotent stem cell.