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Abstract
Functional analysis of R5X4 HIV-1 Envs derived from brain and lymphoid tissues of individuals with AIDS
Gray L.1, Churchill M.2, Cowley D.2, Sterjovski J.1, Ellett A.1, Wesselingh S.2, Gabuzda D.3, Gorry P.1
Objectives: Most neurotropic HIV-1 variants in brain are CCR5-restricted. However, R5X4 variants have been identified occasionally in brain. Here, we characterized full-length R5X4 HIV-1 Envs from autopsy brain and spleen of 1 subject, and from brain and blood of another subject who underwent stereotaxic brain biopsy for diagnosis of CNS lymphoma.
Methods: HIV-1 Envs were cloned from R5X4 viruses isolated from brain (n=6) and spleen (n=6) of subject MACS1. Single R5X4 Envs cloned directly from brain and blood of an additional subject were included (aBR01, aBL01). Coreceptor usage was determined by single-round entry assays. Cell-surface Env expression was determined by flow cytometry. Env fusogenicity and CD4/coreceptor-dependence was tested in cell-cell fusion assays.
Results: All Envs were R5X4 phenotype and expressed at similar levels on transfected cells. Brain Envs from MACS1 and aBR01 were more fusogenic than Envs from matched spleen or blood with target cells expressing CD4/CCR5, whereas MACS1 spleen Envs and the blood-derived aBL01 Env were more fusogenic than Envs from matched brain with target cells expressing CD4/CXCR4. Compared to MACS1 spleen and aBL01 Envs, 3/6 MACS1 brain and the aBR01 Envs had reduced dependence on CCR5 levels in fusion assays. Compared to MACS1 brain Envs, 2/6 MACS1 spleen Envs had reduced dependence on CXCR4 levels in fusion assays. 6/6 MACS1 brain Envs and 4/6 MACS1 spleen Envs had reduced CD4 dependence in fusion assays with target cells expressing CD4/CCR5, whereas 3/6 MACS1 spleen Envs and the aBL01 Env had reduced CD4 dependence in fusion assays with target cells expressing CD4/CXCR4.
Conclusions: Our studies demonstrate enhanced CCR5- or CXCR4-mediated fusogenicity by brain- or spleen/blood-derived R5X4 Envs, respectively. This was associated with altered dependence on coreceptor and/or CD4 levels. The results suggest tissue-specific adaptation of brain- and lymphoid tissue-derived R5X4 Envs with preferential use of CCR5 in brain and CXCR4 in lymphoid tissues.
4th IAS Conference on HIV Pathogenesis, Treatment and Prevention
Abstract no.
MOPEA034
Suggested Citation
"GrayL., et al.
Functional analysis of R5X4 HIV-1 Envs derived from brain and lymphoid tissues of individuals with AIDS.
Poster exhibition:
4th IAS Conference on HIV Pathogenesis, Treatment and Prevention:
Abstract no.
MOPEA034"
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