Antigenic heterogeneity of the hepatitis C virus NS5A protein.
The effect of sequence variability between different types of hepatitis C virus (HCV) on the antigenic properties of the NS5 protein was studied by using recombinant proteins. A strong antigenic region was identified within the HCV NS5A protein at amino acids 2212 to 2313. Forty-five unique sequences encompassing this region were selected from GenBank and were compared to each other. The results of this analysis showed that the primary structure of this strong antigenic region is highly variable. Percent homology between different genotype sequences varied from 40.4 to 72.5%. Thirteen representative sequences from all six HCV genotypes were selected to design synthetic genes coding for this antigenic region. These genes were assembled by PCR from synthetic oligonucleotides and expressed in Escherichia coli as hybrid proteins with glutathione S-transferase. All 13 fusion proteins were purified from bacterial lysates and used to test a panel of anti-HCV positive sera (n = 91) obtained from patients infected with HCV genotypes 1 through 6. All but two proteins immunoreacted with 62 to 93% of HCV anti-NS5-positive serum samples. Although a variable degree of genotype-specific antigenic reactivity was detected, only one protein demonstrated a noticeable preference to immunoreact with antibodies against the homologous HCV genotype. On the other hand, closely related proteins derived from the same subtype or genotype immunoreacted with significantly different efficiency with HCV antibodies. Thus, sequence variability has a profound effect on the antigenic properties of the NS5A immunodominant regions. This observation should be taken into consideration in the development of diagnostic tests for the efficient detection of anti-HCV activity in serum specimens.
Dou
Xiao-Guang
XG
Hepatitis Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Talekar
Ganesh
G
Chang
Joy
J
Dai
Xing
X
Li
Lixia
L
Bonafonte
Maria-Teresa
MT
Holloway
Brian
B
Fields
Howard A
HA
Khudyakov
Yury E
YE
D000595:Amino Acid Sequence; D000940:Antigenic Variation; D018604:Epitope Mapping; D016174:Hepacivirus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology / Q000821:virology; D018937:Hepatitis C Antibodies / Q000097:blood / Q000276:immunology; D006801:Humans; D016056:Immunodominant Epitopes; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D012324:RNA-Dependent RNA Polymerase
D018937:Hepatitis C Antibodies; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase