High titers of antibodies inhibiting the binding of envelope to human cells correlate with natural resolution of chronic hepatitis C

Ishii, Koji; Rosa, Domenico; Watanabe, Yoji; Katayama, Tohru; Harada, Hideharu; Wyatt, Colby A.; Kiyosawa, Kendo; Aizaki, Hideki; Matsuura, Yoshiharu; Houghton, Michael; Abrignani, Sergio; Miyamura, Tatsuo

doi:10.1002/hep.510280429

Cited by 127 publications

(81 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…36 Antibodies against E2 were detected in 88% of chronically infected and in 49% of acutely infected HCV patients. 37 mAbs have been made from such patients and V region sequences have been determined.…”

Section: Discussionmentioning

confidence: 97%

The B-cell receptor of a hepatitis C virus (HCV)–associated non-Hodgkin lymphoma binds the viral E2 envelope protein, implicating HCV in lymphomagenesis

Quinn

Chan

Hadlock

et al. 2001

Blood

193

121

View full text Add to dashboard Cite

Hepatitis C virus (HCV) infection is associated with extrahepatic B-cell lymphoproliferative disorders. To determine whether a viral antigen drives this B-cell expansion, the B-cell receptors were cloned from HCV-associated lymphomas and were expressed as soluble immunoglobulins. The rescued immunoglobulins were then tested for their ability to bind the HCV-E2 envelope glycoprotein, an antigen that was previously implicated in the pathogenesis of HCV-associated B-cell diseases. One of 2 lymphoma immunoglobulin test cases bound the E2 protein in a manner identical to a bona fide human anti-E2 antibody. Moreover, it bound E2 from multiple viral genotypes, suggesting reactivity with a conserved E2 epitope. IntroductionMore than 100 million people worldwide are infected by hepatitis C virus (HCV). 1 Infection causes prolonged and persistent disease in the majority of carriers, often leading to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (reviewed in Houghton 2 and Liang et al 3 ). HCV is also the leading cause of mixed cryoglobulinemia (MC), a systemic immune complex-mediated disorder characterized by polyclonal or monoclonal B-cell proliferation. 4,5 MC can evolve into overt B-cell non-Hodgkin lymphoma (NHL), 6,7 although the incidence of malignant transformation appears to be restricted to certain areas of the world.In type II MC, immunoglobulin immune complexes contain both monoclonal immunoglobulin M (IgM) and polyclonal IgG. 8 The monoclonal IgM has rheumatoid factor (RF) activity and is encoded mostly by a restricted set of variable (V) region genes, specifically V H 1-69 (also known as 51p1) and V3-A27 (also known as v325). 9-12 The same set of V region genes is expressed by the majority of HCV-associated NHL, suggesting a malignant progression from type II MC. 13 Immunoglobulin V region genes expressed by these lymphomas exhibit an ongoing process of somatic mutations, indicative of antigen selection. 13 Moreover, the histologic presentation of many HCV-associated NHLs is typical of germinal center (GC) and post-GC B cells. 14 Therefore, it is likely that lymphomagenesis occurs when B cells proliferate in response to antigen. To date, the antigen driving these extrahepatic lymphoproliferative diseases is unknown.Nevertheless, immune responses occurring in HCV patients against one HCV antigen, the E2 envelope glycoprotein (E2), suggest that the restricted V gene usage seen in the lymphoproliferative disorders may be linked to this antigen. V region genes from human anti-E2 antibodies, derived from B cells of HCV-infected individuals, show similar V gene bias to that observed in HCV-associated MC and NHL. 15,16 These studies implicate the specific immune response to the E2 antigen in the pathogenesis of B-cell lymphoproliferative diseases and potentially in HCV-associated lymphomas.A possibility exists that cognate B cells, which bind E2 via their specific B-cell receptor (BCR) could engage 2 signaling complexes simultaneously-the BCR and the CD19/CD21/CD81 complex (CD81 is the putative E...

show abstract

Section: Discussionmentioning

confidence: 97%

The B-cell receptor of a hepatitis C virus (HCV)–associated non-Hodgkin lymphoma binds the viral E2 envelope protein, implicating HCV in lymphomagenesis

Quinn

Chan

Hadlock

et al. 2001

Blood

193

121

View full text Add to dashboard Cite

show abstract

“…Mouse and guinea pig sera were tested for their ability to inhibit the binding of E2 protein to human target cells as previously described (25,46). Briefly, NOB titers were determined by incubation of MOLT-4 cells with a nonsaturating concentration of biotinylated I-E2 715 protein (1.5 g/ml), which was previously incubated with a test serum at different dilutions.…”

Section: Methodsmentioning

confidence: 99%

Evaluation of Hepatitis C Virus Glycoprotein E2 for Vaccine Design: an Endoplasmic Reticulum-Retained Recombinant Protein Is Superior to Secreted Recombinant Protein and DNA-Based Vaccine Candidates

Heile¹,

Fong²,

Rosa³

et al. 2000

J Virol

Self Cite

View full text Add to dashboard Cite

Hepatitis C virus (HCV) is the leading causative agent of blood-borne chronic hepatitis and is the target of intensive vaccine research. The virus genome encodes a number of structural and nonstructural antigens which could be used in a subunit vaccine. The HCV envelope glycoprotein E2 has recently been shown to bind CD81 on human cells and therefore is a prime candidate for inclusion in any such vaccine. The experiments presented here assessed the optimal form of HCV E2 antigen from the perspective of antibody generation. The quality of recombinant E2 protein was evaluated by both the capacity to bind its putative receptor CD81 on human cells and the ability to elicit antibodies that inhibited this binding (NOB antibodies). We show that truncated E2 proteins expressed in mammalian cells bind with high efficiency to human cells and elicit NOB antibodies in guinea pigs only when purified from the core-glycosylated intracellular fraction, whereas the complex-glycosylated secreted fraction does not bind and elicits no NOB antibodies. We also show that carbohydrate moieties are not necessary for E2 binding to human cells and that only the monomeric nonaggregated fraction can bind to CD81. Moreover, comparing recombinant intracellular E2 protein to several E2-encoding DNA vaccines in mice, we found that protein immunization is superior to DNA in both the quantity and quality of the antibody response elicited. Together, our data suggest that to elicit antibodies aimed at blocking HCV binding to CD81 on human cells, the antigen of choice is a mammalian cell-expressed, monomeric E2 protein purified from the intracellular fraction.Hepatitis C virus (HCV) is the major cause of chronic hepatitis, which can evolve into cirrhosis, liver failure, or hepatocellular carcinoma (2, 4). There is no vaccine for HCV, and the only available treatment, a combination of alpha interferon and ribavirin, is efficacious in only a minority of patients (33).Given that approximately 200 million chronic HCV infections have been estimated worldwide (52), there is a pressing need to develop new therapies and vaccination strategies. The development of such strategies will be aided greatly by a more complete picture of the structure-function features of HCV proteins.HCV is an enveloped plus-strand RNA virus of the Flaviviridae family (24). Its genome is 9.5 kb in length with one open reading frame that is translated as a single polyprotein, which is processed by host and virus proteases into at least three structural and seven presumptive nonstructural proteins with various enzymatic activities (5, 22, 47). Two glycoproteins, E1 and E2, are probably virion envelope proteins, containing multiple N-linked glycosylation sites, and form heterodimers in vitro (23,32,35,45). The coexpressed E1-E2 complex localizes to the endoplasmic reticulum (ER) and lacks complex N-linked glycans (7,8,13,15,45,49).Neutralizing antibodies often play a pivotal role in defeating viral infections, including prominent human pathogens such as influenza virus and hepatitis B...

show abstract

“…Most antibodies that demonstrate broad neutralization of cell binding and/or infection are directed against conformational epitopes within E2. [27][28][29][30][31] Induction of antibodies recognizing conformational epitopes is a challenging task, as these are difficult to mimic, and protein subunit vaccines are more likely to generate strain-restricted responses due to the immuno-dominance of the variable regions. 32 However, we have recently shown that the mouse monoclonal antibody (MAb) AP33 can potently neutralize retroviral pseudo-particles (HCVpp) bearing genetically diverse E1E2 glycoproteins.…”

mentioning

confidence: 99%

Characterization of the hepatitis C virus E2 epitope defined by the broadly neutralizing monoclonal antibody AP33

et al. 2006

View full text Add to dashboard Cite

The mouse monoclonal antibody (MAb) AP33, recognizing a 12 amino acid linear epitope in the hepatitis C virus (HCV) E2 glycoprotein, potently neutralizes retroviral pseudoparticles (HCVpp) carrying genetically diverse HCV envelope glycoproteins. Consequently, this antibody and its epitope are highly relevant to vaccine design and immunotherapeutic development. The rational design of immunogens capable of inducing antibodies that target the AP33 epitope will benefit from a better understanding of this region. We have used complementary approaches, which include random peptide phage display mapping and alanine scanning mutagenesis, to identify residues in the HCV E2 protein critical for MAb AP33 binding. Four residues crucial for MAb binding were identified, which are highly conserved in HCV E2 sequences. Three residues within E2 were shown to be critical for binding to the rat MAb 3/11, which previously was shown to recognize the same 12 amino acid E2 epitope as MAb AP33 antibody, although only two of these were shared with MAb AP33. MAb AP33 bound to a panel of functional E2 proteins representative of genotypes 1-6 with higher affinity than MAb 3/11. Similarly, MAb AP33 was consistently more efficient at neutralizing infectivity by diverse HCVpp than MAb 3/11. Importantly, MAb AP33 was also able to neutralize the cell culture infectious HCV clone JFH-1. In conclusion, these data identify important protective determinants and will greatly assist the development of vaccine candidates based on the AP33 epitope. HCV, a member of the Flaviviridae family, has a 9-kb genome encoding a polyprotein precursor that is cleaved to yield three structural proteins, core, E1, and E2, together with at least six non-structural proteins. E1 and E2 are highly glycosylated membrane-anchored proteins that mediate viral entry. 2-6 E2 has been shown to bind to a number of cell surface molecules. 7-10 Whereas the exact mechanism of viral entry is unknown, mounting evidence indicates that CD81 and SR-BI are key molecules. 2,[4][5][6][11][12][13][14] In an infected individual, HCV exists as a viral quasispecies. 15 HCV can be classified into at least six major genotypes that exhibit extensive genetic variability, particularly in E1 and E2. 16 E1 and E2 are the principle targets for neutralizing antibodies, and identification of protective epitopes conserved across different strains of HCV is a major challenge for vaccine design. 17 A number of antibodies that are capable of blocking E2 binding to cells or cell receptors have been described, 18-23 some of which neutralize HCV entry in animal or in vitro models. 6,[24][25][26] The first hypervariable region of E2 contains potent neutralizing epitopes, and antibodies raised against

show abstract

High titers of antibodies inhibiting the binding of envelope to human cells correlate with natural resolution of chronic hepatitis C

Abstract: Most cases of hepatitis C virus (HCV) infection result inHepatitis C virus (HCV) is the most important causative agent of blood-borne non-A non-B hepatitis, infecting a million people a year worldwide.

Cited by 127 publications

References 26 publications

The B-cell receptor of a hepatitis C virus (HCV)–associated non-Hodgkin lymphoma binds the viral E2 envelope protein, implicating HCV in lymphomagenesis

The B-cell receptor of a hepatitis C virus (HCV)–associated non-Hodgkin lymphoma binds the viral E2 envelope protein, implicating HCV in lymphomagenesis

Evaluation of Hepatitis C Virus Glycoprotein E2 for Vaccine Design: an Endoplasmic Reticulum-Retained Recombinant Protein Is Superior to Secreted Recombinant Protein and DNA-Based Vaccine Candidates

Characterization of the hepatitis C virus E2 epitope defined by the broadly neutralizing monoclonal antibody AP33

Contact Info

Product

Resources

About