COVID-19 preclinical models: human angiotensin-converting enzyme 2 transgenic mice

Table 1 The comparison of outcomes in each hACE2 Tg mouse model to SARS-CoV infection

	K18-hACE2 [66, 67]	AC70, AC22, and AC63 [59, 68]	HFH4-ACE2 [69]	Mouse ACE2 promoter-driven hACE2 Tg mice [70]
Promoter	Human K18 promoter	CAG promoter	Human HFH4 promoter	Mouse ACE2 promoter
Parental mice of zygotes	(C57BL/6J × SJL/J) F2	(C57BL/6J × C3H/HeJ) F1	(C3H × C57BL/6) F1	ICR
Viral strains	Urbani	Urbani	Urbani	PUMC01
TCID50^aof SARS-CoV	1.6 × 10^4b	AC70: 10³ AC22: 10⁶ AC63: 10⁶	7 × 10^4c	10⁵
Mortality (%)	Line 1: 100 Line 2: 100 Line 3: 100	AC70: 100 AC22: 0 AC63: 0	100	0
Survival days (p.i.)	Line 1: 2–5 Line 2: 3–4 Line 3: 5–7	AC70: 4–8 AC22: n.a.^d AC63: n.a.	5–6	n.a.

^aTCID50 50% tissue culture infective dose
^bThe viral dosage used in the study, 2.3 × 10⁴ plaque-forming units (PFU), was converted to the estimated TCID50 by the conversion TCID50 ≈ 0.7 PFU [71].
^cThe viral dosage used in the study, 10⁵ PFU, was converted to the estimated TCID50 by the conversion TCID50 ≈ 0.7 PFU [71].
^dNot applicable

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