Table 1.

Characteristics of virus, important viral protein, entry molecules, recognition molecules and downstream cytokines/chemokines of RV, RSV and SAR-CoV-2.

Virus	Type	Important viral protein for infection	Entry molecules (Receptor)	Recognition molecules (PRRs)	Downstream cytokines/chemokines
RV	Positive- sense ssRNA	VP1 VP3	1) Major RV-A and all RV-B ICAM-1 2) Minor RV-A Low-density lipoprotein receptor 3) RV-C CDHR3	TLR3 (dsRNA) TLR7 (ssRNA) MDA-5 RIG-1	1) Proinflammatory cytokines/chemokines IL-1β, IL-6, IL-8, IL-12, TNF-α, CCL5, CXCL9, CXCL10, GM-CSF, IL-33, TSLP, IL-25 2) IFNs IFN-α, IFN-β, IFN-λ
RSV	Negative-sense ssRNA	G protein F protein SH protein	1) G protein Glycosaminoglycans CX3CR1 Annexin II 2) F protein Nucleolin, Co-receptor EGFR, TLR4 and ICAM-1	TLR3 (dsRNA) TLR7 (ssRNA) TLR4 (F protein) RIG-1 MDA-5
SARS-CoV-2	Positive- sense ssRNA	S1 S2	ACE2 TMPRSS2 (for proteolytic cleavage)	TLR3 (dsRNA) TLR7 (ssRNA) MDA-5 RIG-1