Search

Background and objective: HIV-1 uses co-receptors CCR5 and CXCR4 in addition to CD4 for viral entry into cells. CCR5 is used in the early stages of HIV-1 infection, but viruses that utilize CXCR4 for viral entry emerge in the later stages. This is not common among clade Cstrains, with previous data from India showing the absence of the emergence of CXCR4-using strains. Sequence analysis has demonstrated that the V3 loop plays a very important role in determining the syncytium-inducing (SI) phenotype. The V3 region of the SI variants were observed to have positively charged amino acids at positions 11 and/or 25 and also a overall higher charge. This study looked at co-receptor usage among HIV-1 strains in India from individuals who were antiretroviral therapy (ART) naïve and those not responding to ART. Methods: Amplification and sequencing of the HIV-1 env gp120 V3 region was done on 40 ART-naïve individuals, who were selected for the study based on their CD4 counts, and eight patients who had not responded to ART. The sequences were submitted to Geno2Pheno and Web PSSM. The pol gene sequences of these strains were submitted to the REGA HIV-1 subtyping tool. Results: Forty-seven strains were identified as clade C and one strain as clade A1. Geno2Pheno identified three CXCR4-using strains, and the Web PSSM clade C matrix identified two. Conclusion: We report, for the first time, CXCR4-using strains among HIV-1 clade C strains circulating in India. [ABSTRACT FROM AUTHOR]

Introduction: Morbidity and mortality among HIV-1-infected individuals has been dramatically reduced by the implementation of combinational antiretroviral therapy (ART). However, the efficiency of these therapies is compromised due to HIV-1 transmitted drug resistance mutations (TDRMs). Methods: We collected a total of 127 samples from ART-naïve HIV-infected individuals and sequenced the pol gene and analysed for drug resistance mutations using the Calibrated Population Resistance (CPR) tool in the Stanford database. Results: All the 127 clinical samples (100 %) were identified as HIV-1 subtype C. Based on the CPR tool, three strains (2.4 %) had TDRMs, and these were K101E, Y181C and G190A. Our findings correlated well with the WHO surveys conducted in Asia, including India, which consistently reported <5 % TDRM among the specific populations assessed. Conclusion: In countries like India, regular monitoring of TDRMs will provide better information for clinical practice improvement and policy making. [ABSTRACT FROM AUTHOR]