Serotyping HIV-1 with V3 peptides: detection of high avidity antibodies presenting clade-specific reactivity

The main objective of the present study was to assess the specificity and sensitivity of a modified assay using short synthetic peptides of the V3 region of HIV-1 gp120, which is the main target for neutralizing antibodies. Results from an enzyme immunoassay (EIA) employing a panel of synthetic peptides of HIV-1 subtypes and using urea washes to detect high avidity antibodies (AAV3) were compared with those obtained by the heteroduplex mobility assay and DNA sequencing. The EIA correctly typed 100 percent of subtype B (sensitivity = 1.0; specificity = 0.95), 100 percent of HIV-1 E samples (sensitivity = 1.0; specificity = 1.0), and 95 percent of subtype C specimens (sensitivity = 0.95; specificity = 0.94). In contrast, only 50 percent of subtype A (sensitivity = 0.5; specificity = 0.95), 60 percent of subtype D (sensitivity = 0.6; specificity = 1.0), and 28 percent of subtype F samples (sensitivity = 0.28; specificity = 0.95) were correctly identified. This approach was also able to discriminate in a few samples antibodies from patients infected with B variants circulating in Brazil and Thailand that reacted specifically. The assays described in this study are relatively rapid and simple to perform compared to molecular approaches and can be used to screen large numbers of serum or plasma samples. Moreover, the classification in subtypes (genotypes) may overestimate HIV-1 diversity and a classification into serotypes, based on antigenic V3 diversity or another principal neutralization domain, may be more helpful for vaccine development and identification of variants

Clinical and laboratory characteristics of HIV-1 infection in Zimbabwe

To define the impact of human immunolodeficiency virus (HIV) infection in Africa; clinical and laboratory investigations were conducted on 265 HIV-seropositive outpatients in Zimbabwe. Twenty-four of the study subjects were asymptomatic (ASX); 124 had persistent generalized lympademopathy (PGL); and 117 had AIDS-related complex (ARC). HIV infection was assessed by commercial ELISA; Western blots; synthetic peptide ELISA; and measurement of p24 antigen. Serum immunoglobulins; lympocyte mitogen responses; and CD4+ cell numbers were obrtained in 54 sequential patients. Compared to seronegative subjects meab CD4+ cell numbers were decreased and serum immunoglobulins; particularly IgM and IgG; were increased in all groups of seropositive subjects. [abstract terminated]