Viral and cellular determinants involved in hepadnaviral entry

Table 1 Described binding partners for HBV preS1-domain. Numbering of aminoacids (aa) are given for HBV genotype D

Domain	aa	Described interaction partners/binding factors for HBV	Ref.
preS1	10-36	Hepatoma cells bind to preS1 peptide. Inhibition by peptide-antisera	[41]
	19-25	Binding of recombinant subviral particles containing preS1 to human liver. Inhibition by anti-preS1 aa19-25	[142]
	10-36	PreS1-peptide binding not limited to liver cells, also on extrahepatic sites	[143]
	10-36	Partial homology of preS1 aa10-36 with IgA. HBV entry via IgA-binding receptor?	[144]
	18-25	PreS1 aa18-25 crossreact with IgA alpha-1 chain, IgA and HBV use related receptors?	[145]
	10-36	PreS1 aa10-36 binding to 31 kDa protein on HepG2 cells	[146]
	10-36	PreS1-peptide aa10-36 binds to Interleukin 6 (IL6) but not IL3, IL5 and IL7	[147]
	10-36	CHO cells transfected with IL6 cDNA acquire binding sites for preS1 peptide aa10-36	[148]
	10-36	Isolation of 44 kDa protein (HBV-BP) from HepG2 plasma membranes. Homology to SCCA1, human squamous cell carcinoma antigen 1 (human serpin)	[46]
	preS1-GST	Isolation of p80 binding protein from human hepatocytes. Needs preS1 aa12-20/82-90 for binding. p80 binding also to rat hepatocytes	[149]
	preS1	Anti-idiotypic antisera of antibody inhibiting binding of HBV to HepG2. 35kDa protein homology to Glycerinaldehyde-3-phoshate-dehydrgenase (GAPD)	[150,151]
	preS1/ preS2	50 kDa serum glycoprotein interferes with binding of preS1 and preS2 mabs. Soluble form of plasma membrane Protein on human hepatocytes	[152]
	preS1	Yeast two-hybrid assay I: preS1 domain and human liver cDNA library. Isolation of two unknown proteins.	[153]
	preS1	Yeast two-hybrid assay II: preS1 domain and human liver cDNA library. Isolation of cytoplasmic "nascent polypeptide-associated complex alpha polypeptide" (NACA)	[154]
	HBV particles	Asialoglycoproteinreceptor (ASGPR)I: preS1-but not preS2-mabs inhibited binding of HBV to ASGPR. SHBs did not bind to ASGPR	[44]
	HBV particles	Asialoglycoproteinreceptor (ASGPR) II: HBV uptake by HepG2 and HuH7 (ASGPR+), but not CHO (ASGPR-)	[45]
	HBV particles	Asialoglycoproteinreceptor (ASGPR) III: Desialylated HBV only binds to HepG2. Uptake only by susceptible primary human hepatocytes	[155]
	HBV particles	Asialoglycoproteinreceptor (ASGPR) IV: Increased HBV uptake by HepG2 after desialyation results in HBV infection	[156]

Table 2 Described binding partners for HBV preS2 and S-domains

Domain	aa	Described interaction partners/binding factors for HBV	Ref.
preS2		Binds to polymerised human serum albumin (pHSA). pHSA has affinity to hepatocytes	[157]
		Preincubation of human liver membranes with pHSA induced binding of rec. HBsAg/preS2	[158]
		Natural pHSA only present in minor amount in serum	[159]
	3-16	Natural monomeric HSA binds to preS2 domain aa 3-16	[160]
	3-16	Binding site for pHSA	[161]
	2-24	Polyclonal antisera against preS2 peptide (2-24) neutralised HBV infection of chimpanzees	[71]
	14-32	Immunisation of chimpanzees with preS2 peptide (14-32) protected against infection	[162]
	3-16	PreS2 antisera against aa 3-16 inhibited infection completely, others only partially	[33]
S		Human apolipoprotein H (apo H) binds to small surface protein (SHBs)	[163,164]
		SHBs binds endonexin II, now called annexin V	[165]
		Overexpression of annexin V in rat hepatoma cells supported HBV-infection	[166]
		Yeast-derived SHBs alone did not bind to HBV-susceptible hepatocytes	[34]