Clinical impact of HIV-1 subtype: are there important differences?

Sequential Analysis of the N/O-Glycosylation of Heavily Glycosylated HIV-1 gp120 Using EThcD-sceHCD-MS/MS

Deciphering the glycosylation of the viral envelope (Env) glycoprotein is critical for evaluating viral escape from the host’s immune response and developing vaccines and antiviral drugs. However, it is still challenging to precisely decode the site-specific glycosylation characteristics of the highly glycosylated Env proteins, although glycoproteomics have made significant advances in mass spectrometry techniques and data analysis tools. Here, we present a hybrid dissociation technique, EThcD-sceHCD, by combining electron transfer/higher-energy collisional dissociation (EThcD) and stepped collision energy/higher-energy collisional dissociation (sceHCD) into a sequential glycoproteomic workflow. Following this scheme, we characterized site-specific N/O-glycosylation of the human immunodeficiency virus type 1 (HIV-1) Env protein gp120. The EThcD-sceHCD method increased the number of identified glycopeptides when compared with EThcD, while producing more comprehensive fragment ions than sceHCD for site-specific glycosylation analysis, especially for accurate O-glycosite assignment. Finally, eighteen N-glycosites and five O-glycosites with attached glycans were assigned unambiguously from heavily glycosylated gp120. These results indicate that our workflow can achieve improved performance for analysis of the N/O-glycosylation of a highly glycosylated protein containing numerous potential glycosites in one process. Knowledge of the glycosylation landscape of the Env glycoprotein will be useful for understanding of HIV-1 infection and development of vaccines and drugs.

Study of HIV-1 subtypes in serodiscordant couples attending an integrated counselling and testing centre in Mumbai using heteroduplex mobility analysis and DNA sequencing

AIMS

To determine the prevalent subtypes of HIV-1 in serodiscordant couples.

SETTING

Integrated Counselling and Testing Centre (ICTC), Department of Microbiology.

STUDY DESIGN

Prospective pilot study.

PARTICIPANTS

Thirty HIV-1 serodiscordant couples.

INCLUSION CRITERIA

a) Documentation of HIV-1 infection in one partner and seronegative status in the other, current history of continued unprotected sexual activity within the partnership, demonstration that they have been in a partnership for at least 1 year and are not currently on highly active antiretroviral therapy HAART; b) willingness of both partners to provide written informed consent including consent to continued couple counselling for 3 months.

MATERIALS AND METHODS

HIV-1 subtyping was carried out by heteroduplex mobility analysis (HMA) by amplifying env region; and DNA sequencing by amplifying gag region.

RESULTS

HIV-1 env gene was amplified successfully in 10/30 samples; gag gene, in 25/30 samples; and both env and gag gene were amplified successfully in 5/30 samples. HIV-1 subtype C was detected from 21 samples; subtype B, from 7; and subtype A, from 2. Sample from 1 positive partner was detected as subtype C by env HMA and subtype B by gag sequencing.

CONCLUSION

HIV-1 subtype C was found to be the predominant subtype of HIV-1 in serodiscordant couples attending our ICTC, followed by HIV-1 subtype B and HIV-1 subtype A, respectively. DNA sequencing was found to be the most reliable method for determining the subtypes of HIV-1.

Retrospective analysis of the HIV-1 reverse transcriptase inhibitors' resistance in Silesia, Poland

Background

This study was a retrospective analysis of drug resistance mutations among HIV-1 strains prevalent in Silesia, Poland, from the origin of the epidemic to 2004. The investigations included both type and frequency of the reverse transcriptase inhibitors’ resistance mutations and estimation of the drugs’ resistance levels.

Material/Methods

Proviral DNA, obtained from peripheral blood mononuclear cells of the 101 HIV-1–infected patients, was amplified and sequenced in the pol gene fragment covering the first 256 codons of the reverse transcriptase (RT). Reverse transcriptase inhibitors resistance mutations were determined and interpreted with the HIVdb: Genotypic Resistance Interpretation Algorithm available from the Stanford University HIV Drug Resistance Database. In the examined population, 35 subjects (34.7%) received no antiretroviral treatment by the time of specimen collection.

Results

The overall frequency of the RT inhibitors resistance mutations in the studied population was 15.8%. Substitutions related to the reverse transcriptase inhibitors resistance were identified in 10 pol gene sequences (9.9%), all of them were present in the HIV-1 sequences obtained from persons receiving antiretroviral therapy.

Conclusions

Lack of drug-resistant viruses among treatment-naïve Silesian patients HIV-1-infected before the year 2004 may indicate that there was no transmission of the drug-resistant viruses in the studied population to that time.