Anti-HIV type 1 Polyclonal antibody

HIV-1 often acquires drug-resistant mutations in spite of the benefits of antiretroviral therapy (ART). HIV-1 integrase (IN) is essential for the concerted integration of HIV-1 DNA into the host genome. IN further contributes to HIV-1 RNA binding, which is required for HIV-1 maturation. Non-catalytic-site integrase inhibitors (NCINIs) have been developed as allosteric IN inhibitors, which perform anti HIV-1 activity by a multimodal mode of action such as inhibition of the IN-lens epithelium-derived growth factor (LEDGF)/p75 interaction in the early stage and disruption of functional IN multimerization in the late stage of HIV-1 replication. Here, we show that IN undergoes an adaptable conformational change to escape from NCINIs. We observed that NCINI-resistant HIV-1 variants have accumulated 4 amino acid mutations by passage 26 (P26) in the IN-encoding region. We employed highperformance liquid chromatography (HPLC), thermal stability assays, and X-ray crystallographic analysis to show that some amino acid mutations affect the stability and/or dimerization interface of the IN catalytic core domains (CCDs), potentially resulting in the severely decreased multimerization of full-length IN proteins (IN undermultimerization). This undermultimerized IN via NCINI-related mutations was stabilized by HIV-1 RNA and restored to the same level as that of wild-type HIV-1 in viral particles. Recombinant HIV-1 clones with IN undermultimerization propagated similarly to wild-type HIV-1. Our study revealed that HIV-1 can eventually counteract NCINI-induced IN overmultimerization by IN undermultimerization as one of the escape mechanisms. Our findings provide information on the understanding of IN multimerization with or without HIV-1 RNA and may influence the development of anti HIV-1 strategies. IMPORTANCE Understanding the mechanism of HIV-1 resistance to anti-HIV-1 drugs could lead to the development of novel drugs with increased efficiency, resulting in more effective ART. ART composed of more potent and long-acting anti-HIV-1 drugs can greatly improve drug adherence and also provide HIV-1 prevention such as pre exposure prophylaxis. NCINIs with a multimodal mode of action exert potent anti HIV-1 effects through IN overmultimerization during HIV-1 maturation. However, HIV-1 can acquire some mutations that cause IN undermultimerization to alleviate NCINI-induced IN overmultimerization. This undermultimerized IN was efficiently stabilized by HIV-1 RNA and restored to the same level as that of wild-type HIV-1. Our findings revealed that HIV-1 eventually acquires such a conformational escape reaction to overcome the unique NCINI actions. The investigation into drug-resistant mutations associated with HIV-1 protein multimerization may facilitate the elucidation of its molecular mechanism and functional multimerization, allowing us to develop more potent anti-HIV-1 drugs and unique treatment strategies.

Objectives: This study aims to analyze the association of the presence of common polymorphisms [single nucleotide polymorphisms (SNPs)] on Toll-like receptors (TLRs), such as TLR9-1635A/G, TLR2-1892A/C, TLR2-2258G/A, TLR4-899A/G, and TLR4-1196C/T, with the viral rebound after stopping antiretroviral treatment (ART). CCR5-Delta 32 deletion and HLA-A/HLA-B alleles were also analyzed. Design: Interruption of ART may be required to investigate the outcome of strategies aimed to achieve drug-free HIV remission or cure. However, interruption of ART is currently not indicated. This was a retrospective longitudinal study that included 57 long-term suppressed HIV-1-infected individuals. Methods: TLR SNPs were detected by real-time polymerase chain reaction (PCR). CCR5-Delta 32 was analyzed by conventional PCR and HLA-A and HLA-B alleles by PCR-SSOP Luminex. Results: HIV-1 RNA rebound at week 4 after treatment interruption positively correlated with pre-ART HIV-1 load (P= 0.025). The TLR9-1635AA genotype was independently associated with a higher HIV-1 rebound compared with those with AG + GG genotype (multivariate stepwise regression analysis,P= 0.004). Women had lower HIV-1 RNA load both at rebound and during the 72 weeks of follow-up compared with men (P< 0.05 at all time-points), whereas CD4 nadir and CD4 count set-point were similar according to sex. The pre-ART viral load was independently associated with the viral set-point (P= 0.001), whereas the presence of the HLA-A01 allele (P= 0.027) and the CD4 nadir (P= 0.001) were associated with the CD4 count set-point. Conclusions: The association of the TLR9-1635AA genotype with a higher HIV-1 rebound suggests that this SNP may affect the results from strategies requiring interruption of ART aimed to cure HIV-1 infection.