Correlation of Genetic and Serologic Approaches to HIV-1 Subtyping in Thailand

Abstract

The aim of this study was to compare the performance of differential polymerase chain reaction (PCR) typing and peptide enzyme-linked immunosorbent assay (V3-EIA) for human immunodeficiency virus type 1 (HIV-1) subtyping in Thailand using heteroduplex mobility assay (HMA) as the reference standard. Paired peripheral blood mononuclear cells (PBMC) and sera were collected from 38 HIV-1 seropositive persons in Thailand. HMA was done by standard methods; differential PCR employs primer pairs that differentially amplify either subtype E or B. V3-EIA used peptides specific for subtypes E or B. Thirty-two cases (84%) were found by HMA to be infected with subtype E: and six with (16%) subtype B. The results obtained with differential PCR were 100% concordant with those of HMA; V3 EIA correctly predicted the subtype in 95% (36 of 38). Six samples that molecularly subtyped as E were repeatedly dual reactive by screening V3-EIA, but these resolved to subtype E using an antigen-limiting EIA. Two samples were serologically nontypeable because of overall low levels of V3 antibody. Using HMA as the standard, differential PCR was shown to subtype HIV-1 reliably from patient PBMC samples. V3-EIA correctly predicted HIV-1 subtype in most (95%) of our cases. Because of the less rigorous sampling requirements, specimen processing, and logistical and technical requirements of serotyping compared with molecular techniques, it appears to be practical for screening purposes in a field environment. Samples that cannot be definitively subtyped serologically should undergo differential PCR and antigen-limiting V3 EIA. These approaches to HIV-1 subtyping should be used in complementary fashion in Thailand, where subtypes B and E are currently known to cocirculate.

Human Immunodeficiency Virus Type 1 Subtype E Envelope Recombinant Peptides Containing Naturally Immunogenic Epitopes

“…Because of its highly immunogenic nature, the possibility of using subtype-specific V3 peptides to distinguish different HIV-1 subtypes has been investigated [36][37][38]. For instance, V3 serotyping was found to be useful in distinguishing HIV-1 subtype E from subtype B in Thailand [59][60][61]. Our finding that all 58 sera studied reacted with peptide F is in agreement with previous reports that the V3 loop is an immunogenic domain.…”

Characterization of a Virtually Full-Length Human Immunodeficiency Virus Type 1 Genome of a Prevalent Intersubtype (C/B′) Recombinant Strain in China

“…Phylogenetic analyses of globally circulating HIV strains have identified a major group (M) of 10 different sequence subtypes (A to J) (13,19,20,39) exhibiting sequence variations in the envelope protein of up to 24%, in addition to group O viruses, which differ from group M viruses by more than 40% in some reading frames (22,23,33,34). Although the extent of global HIV-1 variation is well defined, little is known about the biological consequences of this genetic diversity and its impact on the design of candidate vaccines.…”

Expression of monocyte markers in HIV-1 infected individuals with or without HIV associated dementia and normal controls in Bangkok Thailand

“…CD4 percent was obtained with BD TriTEST ™ reagents (Becton Dickinson, San Jose, CA), and white blood cell counts were obtained by using cell counter (Coulter Max-M ™ Burlington, Ontario, Canada). Viral subtype was determined by the AFRIMS Retrovirology laboratory using V3 loop peptide ELISA serotyping, as previously described (Gaywee et al, 1996) The peptides used were V3-CM237 (Thai subtype B) and V3 CM242 (CRF01_AE). This approach has previously been shown to distinguish HIV-1 subtype B and CRF01-AE infection in Thai individuals (Mason et al, 1998;Polonis et al, 2001).…”