In Vitro Models for Studying Entry, Tissue Tropism, and Therapeutic Approaches of Highly Pathogenic Coronaviruses

Table 1

CD26/DPP4 and ACE2 receptor expression in different primate cell lines.

Cell line	Origin	Expression marker	Level	Method of evaluation	Virus	Reference
Nonhuman cells:
Vero, Vero E6	African green monkey kidney	CD26/DPP4	N/R	Immunofluorescence	MERS-CoV	[90]
		CD26/DPP4	High	Flow cytometry (FACS), immunofluorescence	MERS-CoV	[27]
		CD26/DPP4	High	Flow cytometry (FACS), western blot	MERS-CoV	[28]
		CD26/DPP4	High	Flow cytometry (FACS), protein electrophoresis	MERS-CoV	[29]
		CD26/DPP4	Low	Real-time RT-PCR, western blot	MERS-CoV	[25]
		CD26/DPP4	Int.	Western blot	MERS-CoV	[79]
		CD26/DPP4	High	Flow cytometry (FACS)	MERS-CoV	[83]
		CD26/DPP4	Int.	Quantitative RT-PCR	MERS-CoV	[91]
		CD26/DPP4	Int.	Quantitative RT-PCR, flow cytometry (FACS)	MERS-CoV	[92]
		CD26/DPP4	High	Immunofluorescence	MERS -CoV	[93]
		ACE2	High	Real-time RT-PCR	SARS-CoV	[17]
		ACE2	High	RT-PCR	SARS-CoV	[60]
		ACE2	Int.	Immunofluorescence	SARS-CoV	[93]
		ACE2	High	Western blot	SARS-CoV	[94]
		ACE2	Int.	Flow cytometry (FACS)	SARS-CoV	[95]
		ACE2	High	Immunofluorescence	SARS-CoV	[96]
LLC-MK2	Rhesus monkey kidney	ACE2	High	Flow cytometry (FACS), immunofluorescence	SARS-CoV	[97]
		ACE2	High	Immunostaining	HCoV-NL63	[98]
Human cells:
MRC-5	Lung cells Medical Research Council-5	CD26/DPP4	High	Quantitative RT-PCR	MERS -CoV	[99]
A549	Human lung adenocarcinoma	CD26/DPP4	Low	Enzymatic activities, immunohistochemistry (IHC)	-	[100]
		CD26/DPP4	N/R	Flow cytometry (FACS)	-	[101]
		CD26/DPP4	N/R	Immunofluorescence	MERS -CoV	[90]
		CD26/DPP4	Low	Western blot	MERS-CoV	[79]
		ACE2	N/R	Western blot	-	[102]
		ACE2	High	Immunostaining	SARS-CoV	[58]
		ACE2	Low	Immunoblot	SARS-CoV	[70]
Calu-3	Human lung cancer cells	CD26/DPP4	High	Immunofluorescence	MERS-CoV	[30]
		CD26/DPP4	High	Real-time RT-PCR, western blot	MERS-CoV	[25]
		CD26/DPP4	Int.	Real-time RT-PCR	MERS-CoV	[103]
		CD26/DPP4	High	Flow cytometry (FACS)	MERS-CoV	[82]
		ACE2	High	Flow cytometry (FACS), immunofluorescence	SARS-CoV	[104]
		ACE2	High	Real-time RT-PCR	SARS-CoV	[105]
		ACE2	High	Flow cytometry (FACS), western blot	-	[106]
		ACE2	Low	Immunofluorescence	SARS-CoV	[96]
HEp-2	Human respiratory tract	ACE2	High	RT-PCR	SARS-CoV	[60]
		CD26/DPP4	Neg.	Western blot	MERS-CoV	[79]
Huh-7	Hepatocellular carcinoma	CD26/DPP4	High	Flow cytometry (FACS), immunofluorescence	MERS-CoV	[27]
		CD26/DPP4	High	Flow cytometry (FACS), western blot	MERS-CoV	[28]
		CD26/DPP4	High	Flow cytometry (FACS), protein electrophoresis	MERS-CoV	[29]
		CD26/DPP4	N/R	Flow cytometry (FACS)	MERS-CoV	[107]
		CD26/DPP4	High	Real-time RT-PCR	MERS-CoV	[103]
		CD26/DPP4	High	Western blot	MERS-CoV	[79]
		CD26/DPP4	Int.	Quantitative RT-PCR	MERS-CoV	[99]
		ACE2	High	Real-time RT-PCR	SARS-CoV	[17]
		ACE2	High	RT-PCR	SARS-CoV	[60]
		ACE2	Neg.	Flow cytometry (FACS), western blot	-	[106]
LoVo	Human colorectal adenocarcinoma	ACE2	Int.	Real-time RT-PCR	SARS-CoV	[61]
		CD26/DPP4	High	Real-time RT-PCR	MERS-CoV	[103]
Caco-2	Human intestinal tract	CD26/DPP4	Int.	Western blot	MERS-CoV	[79]
		CD26/DPP4	High	Quantitative RT-PCR	MERS-CoV	[91]
		CD26/DPP4	High	Quantitative RT-PCR, flow cytometry (FACS)	MERS-CoV	[92]
		ACE2	Low	Flow cytometry (FACS), western blot	-	[106]
		ACE2	High	Immunofluorescence	SARS-CoV	[96]
		ACE2	High	RT-PCR	-	[108]

Abbreviations: ACE2: angiotensin-converting enzyme 2; DPP4: dipeptidyl peptidase 4; CD26: cluster of differentiation 26; SARS-CoV: severe acute respiratory syndrome coronavirus; MERS-COV: Middle East respiratory syndrome coronavirus; Int.: intermediate; N/R: not reported.