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

Table 2

In vitro models for studying cell entry and tissue tropism of different pathogenic coronaviruses.

Cell lines	Origin	Virus	Main finding related to cell entry and tissue tropism	Reference
Nonhuman cells:
Vero	African green monkey kidney	SARS-CoV	TMPRSS2 is involved in virus entry.	[22]
		SARS-CoV	Cathepsin L inhibitor blocked SARS-CoV infection.	[124]
		SARS-CoV	Small-molecule compounds could perturb the infectivity of the virus.	[125]
		SARS-CoV	Sensitivity of S-mediated entry to protease inhibitors.	[21]
		SARS-CoV	ACE2 as SARS-CoV S pseudovirion receptor for entry.	[8]
		SARS-CoV	Receptor blocked by polyclonal goat anti-hACE2.	[97]
		SARS-CoV-2	ACE2 as SARS-CoV-2 S pseudovirion receptor for entry.	[8]
		MERS-CoV	Furin inhibitor significantly decreased S-mediated entry.	[99]
		MERS-CoV	DPP4 as the receptor for viral entry.	[28, 29]
		MERS-CoV	DPP4 is expressed on permissive cell.	[90]
		MERS-CoV	HR2P significantly inhibited virus replication.	[46]
		MERS-CoV	Simultaneous treatment with inhibitors of cathepsin L and TMPRSS2 completely blocked virus entry.	[25]
VeroE6	African green monkey kidney	SARS-CoV	Rabbit antisera effectively blocked binding of S1 to ACE2.	[126]
		SARS-CoV	ACE2 as the receptor for viral entry.	[127]
		SARS-CoV	Anti-ACE2 blocked viral entry.	[31]
		SARS-CoV	Protease Inhibitors (leupeptin, Z-lll-FMK) blocked SARS-CoV S-mediated entry.	[21]
		SARS-CoV	Proteases enhanced virus entry.	[128]
		SARS-CoV	Vimentin as a coreceptor involved in the virus entry.	[68]
		SARS-CoV	Different host cell proteases activate SARS-S for virus–cell and cell–cell fusion.	[129]
		SARS-CoV	Cholesterol extraction by MβCD treatment could reduce the expression level of cell surface ACE2 at a dose-dependent manner.	[95]
		SARS-CoV-2	SARS-CoV S polyclonal Abs inhibited SARS-CoV-2 spike mediated entry.	[39]
LLC-MK2	Rhesus monkey kidney	SARS-CoV	ACE2 as the receptor for viral entry.	[97]
COS-7	Monkey kidney	MERS-CoV	Expression of human and bat DPP4 allowed MERS-CoV S1–Fc cell surface binding, and viral entry.	[29]
BHK	Baby hamster kidney	SARS-CoV	ACE2 as the receptor for viral entry.	[97]
		SARS-CoV	Proteolytic cleavage within S2 exposes a novel internal fusion peptide for SARS-CoV S.	[130]
		SARS-CoV, SARS-CoV-2	ACE2 as the receptor for viral entry.	[131]
		SARS-CoV-2	ACE2 and host proteases requirement for viral entry.	[132]
		MERS-CoV	hDPP4 transfected cells became permissive.	[133]
		MERS-CoV	Virus could infect human and bat cells expressing DPP4.	[134]
		MERS-CoV	Specific binding between CD26 and MERS-CoV RBD.	[48]
C6	Rat glioma-derived	SARS-CoV	No apparent cytopathic effects (CPE) by infection but produced virus with infectivity of 102–5 per ml. No expression of ACE2	[117]
Human cells:
A549	Lung adenocarcinoma	MERS-CoV	DPP4 is expressed on permissive cells.	[90]
OL	Oligodendroglioma-derived	SARS-CoV	No apparent cytopathic effects (CPE) by infection but produced virus with infectivity of 102–5 per ml. No expression of ACE2	[117]
Calu-3	Airway epithelium	SARS-CoV	hACE2 was required for cell entry.	[118]
		SARS-CoV	Anti-ACE2 Ab blocked the cell entry in a dose-dependent manner.	[104]
		SARS-CoV	ACE2, the SARS-CoV S pseudovirion receptor for entry.	[8]
		SARS-CoV	Simultaneous treatment of the cells with camostat and EST efficiently prevented both cell entry and the multistep growth of the virus in the cells.	[105]
		SARS-CoV-2	ACE2 as the SARS-CoV-2 S pseudovirion receptor for entry.	[8]
		MERS-CoV	DPP4 is expressed on permissive cells.	[30]
		MERS-CoV	TMPRSS2 inhibitor (camostat) blocked virus entry.	[25]
Huh-7	Hepatocellular carcinoma	SARS-CoV	S-mediated entry of pseudotypes requires low pH, S is a target for neutralizing antibodies.	[135]
		SARS-CoV	ACE2 as the SARS-CoV S pseudovirion receptor for entry.	[8]
		SARS-CoV-2	ACE2 as the SARS-CoV-2 S pseudovirion receptor for entry.	[8]
		MERS-CoV	Anti-CD26 mAbs (2F9) inhibited viral entry.	[78]
		MERS-CoV	pAbs to the MERS-CoV S1 efficiently neutralize virus infection.	[136]
		MERS-CoV	Furin inhibitor significantly decreased S-mediated entry.	[99]
		MERS-CoV	DPP4 as the receptor for viral entry.	[28, 29]
		MERS-CoV	Nanobodies significantly blocked RBD binding to DPP4.	[137]
		MERS-CoV	Antihuman CD26/DPP4 antibody inhibited MERS-CoV infection.	[27]
		MERS-CoV	S protein-mediated cell–cell fusion and syncytium formation.	[46]
		MERS-CoV	Interaction between recombinant RBDs and DPP4.	[107]
HEK293T	Embryonic kidneys	SARS-CoV	Cathepsin L inhibitor blocked S mediated pseudovirus entry in ACE2+ cells.	[124]
		SARS-CoV	Lactoferrin blocked the binding of S protein to ACE2 transfected cells.	[138]
		SARS-CoV-2	Binding of polyclonal rabbit anti-SARS S1 antibodies to SARS-CoV-2.	[8]
		MERS-CoV	hDPP4 transfected cells became permissive.	[133]
		MERS-CoV	High levels of hDPP4 and furin enhanced viral entry. Knocked down furin expression with siRNA significantly reduced the pseudovirus entry.	[10]
293T	Embryonic kidney epithelial	SARS-CoV	S Protein efficiently binds ACE2.	[139]
		SARS-CoV	Neutralization of SARS pseudovirus infection by mouse antisera.	[140]
		SARS-CoV	TMPRSS2 protease-dependent viral entry.	[141]
		SARS-CoV	Protease inhibitors (leupeptin, E64c) blocked SARS-CoV S-mediated entry.	[21]
		SARS-CoV	Cytoplasmic domain was not essential for ACE2-mediated viral entry; soluble ACE2 inhibited S-bearing pseudotype entry.	[60]
		SARS-CoV	Rabbit antisera effectively blocked binding of S1 to ACE2.	[126]
		SARS-CoV	ACE2 was required for entry.	[31]
		SARS-CoV	SARS-CoV RBD protein inhibited virus entry.	[18]
		SARS-CoV	ACE2 as the SARS-CoV S pseudovirion receptor for entry.	[8]
		SARS-CoV	MAbs inhibited RBD-Fc binding to ACE2.	[142, 143]
		SARS-CoV	A compound (designated VE607) inhibited pseudovirus entry.	[125]
		SARS-CoV	ACE2 as the SARS-CoV S pseudovirion receptor for entry.	[81]
		SARS-CoV	TMPRSS2-mediated proteolysis of both S and ACE2 enhanced viral entry.	[23]
		SARS-CoV	S-mediated entry of lentiviral-based vectors.	[144]
		SARS-CoV	Proteases activated SARS-S-driven virus-cell fusion.	[145]
		SARS-CoV	Host cell proteases activated SARS-S for virus–cell and cell–cell fusion.	[129]
		SARS-CoV-2	ACE2 as the SARS-CoV-2 S pseudovirion receptor for entry.	[8]
		SARS-CoV-2	Protease was required for S-driven entry.	[131]
		SARS-CoV-2	SARS-CoV-2 RBD protein inhibited both SARS- and SARS-CoV-2 entry.	[18]
		MERS-CoV	MERS-CoV RBD inhibited MERS-CoV pseudovirus entry.	[18]
HeLa	Cervical adenocarcinoma	SARS-CoV	TMPRSS2 enhanced pseudotyped SARS-S and authentic SARS-CoV entry, and camostat blocked it.	[105]
		SARS-CoV-2	ACE2 was required for viral entry.	[146]
JKT-hCD26	Human T cell leukemia	MERS-CoV	Anti-CD26 mAbs (2F9) inhibited viral entry.	[78]
LoVo	Colorectal adenocarcinoma	SARS-CoV	ACE2 is expressed on permissive cell.	[61]
		MERS-CoV	DPP4 is expressed on permissive cell.	[30]
Caco-2	Colorectal adenocarcinoma	SARS-CoV-2	Protease was required for S-driven entry.	[131]
		MERS-CoV	Protease (TMPRSS2 and cathepsin B/L) could activate EMC-S for entry.	[81]
Primary culture
HBEpC	Primary bronchial epithelial cell	SARS-CoV, MERS-CoV	Specific receptors were needed for cell entry.	[93]
HREpC	Primary renal epithelial cells	SARS-CoV, MERS-CoV	Specific receptors were needed for cell entry.	[93]
HAE	Airway epithelium	SARS-CoV	hACE2 as the primary receptor for entry.	[118]
		SARS-CoV	S protein-pseudotyped FIV infected differentiated cells abundantly express ACE2 from the apical surface.	[70]
		MERS-CoV	Both type I and type III IFN efficiently reduced MERS-CoV replication.	[147]
		MERS-CoV	TMPRSS2 inhibitor (camostat) blocked virus entry.	[25]
NHBE	Normal human bronchial epithelial	MERS-CoV	Furin inhibitor significantly decreased S-mediated entry.	[99]
3D human organoids	Induced pluripotent stem cells- (iPSCs-) derived	SARS-CoV-2	The impact of SARS-CoV-2 as a neurotropic virus and emphasize that brain organoids could model CNS pathologies of COVID-19	[110]
		SARS-CoV-2	Neuronal infection can be prevented either by blocking ACE2 with antibodies or by administering cerebrospinal fluid from a COVID-19 patient.	[113]
		SARS-CoV-2	Using hPSCs to generate multiple different cell and organoid derivatives to study the viral tropism and cellular responses to infection.	[112]
		SARS-CoV-2	SARS-CoV-2 can infect neural cells. detected the expression of the ACE2 receptor, but not TMPRSS2, in the model.	[111]
		SARS-CoV-2	ACE2 expresses in cultured human pluripotent stem cell- (PSC-) derived mixed neurons.	[114]