Search

The complete 154-kbp linear double-stranded genomic DNA sequence of herpes simplex virus 2 (HSV-2), consisting of two extended regions of unique sequences bounded by a pair of inverted repeat elements, was published in 1998 and since then has been widely employed in a wide range of studies. Throughout the HSV-2 genome are scattered 150 microsatellites (also referred to as short tandem repeats) of 1- to 6-nucleotide motifs, mainly distributed in noncoding regions. Microsatellites are considered reliable markers for genetic mapping to differentiate herpesvirus strains, as shown for cytomegalovirus and HSV-1. The aim of this work was to characterize 12 polymorphic microsatellites within the HSV-2 genome by use of 3 multiplex PCR assays in combination with length polymorphism analysis for the rapid genetic differentiation of 56 HSV-2 clinical isolates and 2 HSV-2 laboratory strains (gHSV-2 and MS). This new system was applied to a specific new HSV-2 variant recently identified in HIV-1-infected patients originating from West Africa. Our results confirm that microsatellite polymorphism analysis is an accurate tool for studying the epidemiology of HSV-2 infections.

We analyzed 3,475 human immunodeficiency virus sequences and 241 therapeutic histories. The L74I mutation was carried by 7% of viruses. L74I was strongly associated with T215F, K70R, and V75M/S/T/A mutations and increased with the number of thymidine analog mutations. It seemed to be linked to the use of abacavir or efavirenz.

Viral loads in 249 clinical samples from individual patients infected with human immunodeficiency virus type 1 non-B subtypes were determined with both the Abbott RealTime and Cobas TaqMan assays. The differences exceeded 0.5 log for about 20% of samples and 1 log for 3%, with higher values always from the Abbott assay in the latter cases.

The sensitivity of the enzyme-linked amplified sorbent test (ELAST) was compared with those of other classic enzyme-linked immunosorbent assays (ELISAs), with or without previous acidic immunocomplex dissociation (ICD), in a series of samples at different stages of human immunodeficiency virus type 1 (HIV-1) infection. The limit of viral detection of ELAST was assessed with fresh HIV-1 preparations quantified by reverse transcription-PCR and with the P24 antigen (Ag) Sanofi Pasteur Calibrator containing lyophilized virus. The P24 Ag detection capacity of ELAST was compared with that of NASBA in samples obtained from infected subjects with less than 250 CD4 + cells. The results of the present study show that ELAST was the most sensitive method for detecting P24 Ag compared to classic ELISA and ICD plus ELISA. ELAST was able to detect 0.5 pg of P24 Ag per ml in a whole virus preparation and the equivalent of 330 to 1,000 RNA copies/ml of HIV. The rate of detection of P24 Ag was always higher in subjects with low levels of anti-P24 antibodies. The number of positive results was dramatically enhanced (from 37% to 94% for subjects with + cells) when the incubation period was prolonged from 1 to 16 h. In a third series of 84 samples (+ cells) tested in parallel, NASBA yielded 83% of the positive results and ELAST yielded 79%. Considering the high sensitivity, low cost, simplicity of equipment (only a plate reader), and possibility for full automation, ELAST appears to be a promising new tool for measuring viral load, especially in areas with few resources, in which the procedures based on molecular biology techniques may be difficult to install.

The large underestimations of HIV RNA quantification observed in 17 patients with the first version of Cobas TaqMan assay have been successfully corrected in the upgraded version 2.0. In comparison with the Abbott RealTime assay, the mean difference that was 1.18 log 10 copies/ml is now zero. The discrepancies have disappeared.