An ELISA for the detection of antibody to the core antigen of hepatitis C virus: use in diagnosis and analysis of indeterminate samples.
OBJECTIVE
In order to examine more carefully the natural history of hepatitis C virus infection and to determine a role for anti-core in the discrimination of indeterminate samples, a solid phase ELISA to detect antibody of the immunoglobulin G class to the hepatitis C virus core antigen was developed using purified protein expressed in Escherichia coli from a major portion of the core antigen coding region.


RESULTS
In a study which examined 651 samples submitted for routine testing by a commercial ELISA (Ortho), only 11 samples showed discrepant results; of these, 10 were Ortho ELISA positive, anti-core negative and one was Ortho ELISA negative anticore positive. Supplemental tests showed that 5/10 of these samples were anti-HCV negative by RIBA and the reciprocal 5 were negative for anti-C22 but positive for anti-C100 and anti-C33. The Ortho ELISA negative, anticore positive sample was weakly positive for anti-C22. The anti-core ELISA was then used to examine 67 indeterminate samples from the blood bank; 11/11 samples which were HCV-RNA positive were anti-core positive and 7/56 samples which were HCV-RNA negative were anti-core positive. The anti-core titre was then examined in two groups of indeterminate samples; group 1, polymerase chain reaction-positive, anti-core positive and group 2, polymerase chain reaction-negative, anti-core positive. The geometric mean anti-core titres in these groups were 1 x 10(-3.6) and 1 x 10(-2.3), respectively. Thus in this group of indeterminate samples, all samples (except one) with an anti-core titre > or = 1/200 were polymerase chain reaction-positive, confirming a close correlation between anti-core levels and hepatitis C viraemia. Anti-core was detected with equal efficiency in patients infected with genotypes which differed to that used to express the recombinant core antigen.
Trowbridge
R
R
Sir Albert Sakzewski Virus Research Centre, Royal Children's Hospital, Brisbane, Australia.
Sloots
T P
TP
Buda
P
P
Faoagali
J
J
Hyland
C
C
Young
I
I
Gowans
E J
EJ
D000918:Antibody Specificity; D001771:Blood Banks / Q000592:standards; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D006526:Hepatitis C / Q000175:diagnosis*; D018937:Hepatitis C Antibodies / Q000302:isolation & purification*; D018936:Hepatitis C Antigens / Q000276:immunology*; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D012107:Research Design; D017186:Titrimetry; D014766:Viremia / Q000276:immunology
D018937:Hepatitis C Antibodies; D018936:Hepatitis C Antigens