Comparative analysis of HIV-1 and HIV-2 indeterminate western blot patterns

Abstract

A comparison of HIV-1 and HIV-2 indeterminate Western blot patterns of Ghanaian sera collected between 1989 and 1990 was made. Antibodies to group specific antigen (GAG) gene products were most frequently detected both HIV-1 and HIV-2 indeterminate sera. HIV-2 GAG gene product p26 was shown to be a non-specific indicator of infection. Antibody to gp120, and envelope gene product of HIV-1 never occurred in indeterminate sera whereas antibodies to all the envelope gene products of HIV-2 were detected in indeterminate sera.

PIP: A comparison of HIV-1 and HIV-2 indeterminate Western blot patterns of Ghanaian sera collected between 1989 and 1990 was made and interpreted according to new World Health Organization (WHO) criteria. For HIV-1 antibodies detection, Novopath Immunoblot assay kits were used. New LavblotII kits were used for detecting HIV-2 antibodies. In both cases, proteins of the specific virus type were used to detect anti-HIV proteins in sera by the enzyme linked immunoelectrotransfer blot (Western blot) technique. Sera and plasma after screening by enzyme-linked immunosorbent assay (ELISA) were used. Antibodies to group specific antigen (GAG) gene products were most frequently detected both HIV-1 and HIV-2 indeterminate sera. HIV-2 GAG gene product p26 was shown to be a non-specific indicator of infection. Analysis of HIV-1 indeterminate Western blot patterns showed the frequency of protein bands for 231 HIV-1 indeterminate sera. Antibodies for the GAG gene products, i.e., anti-55, anti-p24, and anti-p18 had high frequencies of occurrence with anti-p24 occurring 90.5% of the time. Analysis of HIV-2 indeterminate Western blot patterns showed the frequency of appearance of antibodies to the various viral gene products in 396 HIV-2 indeterminate sera. The GAG gene product p26 reacted with most (91.2%) of the 396 indeterminate sera. Comparison of HIV-1 and HIV-2 indeterminate Western blot patterns indicated that antibodies to p26 appeared 25% of the time in the negative control sera for HIV-2, whereas no antibodies to HIV-1 products were detected in any of the HIV-1 negative control sera. In the Western blot analysis using the WHO criteria, the frequencies of appearance of antibodies to the high molecular weight core proteins of p24 (HIV-1) and p26 (HIV-2) were both quite high (90%). No antibody to the external envelope protein was detected for HIV-1 (anti-gp120), whereas antibody to a similar protein (anti-gp 105) was detected in 4.3% of the HIV-2 indeterminate sera.