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Central nervous system (CNS) derived human immunodeficiency virus type 1 (HIV-1) subtype C long terminal repeat (LTR) genetic and functional variation mediates high viral load in this compartment of tuberculous meningitis (TBM) co-infected patients.

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Background: Human immunodeficiency virus type 1 (HIV-1) ribonucleic acid (RNA) is characteristically lower in the central nervous system (CNS) than in plasma of antiretroviral treatment naïve patients. Paradoxically, there is higher HIV-1 viral load in the cerebral spinal fluid (CSF) than plasma of treatment naïve patients co-infected with tuberculous meningitis (TBM). The mechanisms that govern high viral replication in the CNS of TBM co-infected antiretroviral therapy naïve patients remain to be determined. Methodology: The study population comprised of 17 TBM and 3 non-TBM participants selected from an HIV-1 positive and TBM co-infected cohort. The HIV-1 viral RNA was reversed transcribed into complementary deoxyribonucleic acid (cDNA) thus the U3/R region of 3’ long terminal repeat (LTR) was amplified from CSF and plasma RNA by KAPA HiFi HotStart PCR Kits (ThermoFisher Scientific, Invitrogen™, USA). The patients CSF and plasma derived LTR were subsequently cloned into a pGL3 plasmid and further transfected in Jurkat and Astrocyte cell lines to assess the LTR transcriptional activity using Bright-Glo™ Luciferase Assay System (Promega, Madison, WI, USA). Results: CSF derived LTR had a significantly (p<0.0001) higher basal and Tat induced transcriptional activity compared to plasma derived LTR in Astrocyte (SVG) cell line. Similarly, CSF derived LTR had significantly higher (p=0.0024) Tat induced transcriptional activity compared to plasma derived LTR in Jurkat cell lines. LTR sequences containing an Adenine (A) at position 5 of the Sp1III binding site were associated with significantly high basal (p<0.0001) and Tat induced (p=0.0002) transcriptional activity compared to the LTR sequences containing a Thymine (T) at the same position when it was assessed in SVG cell. A similar case was observed in Jurkat cell lines. Consistently, CSF LTR sequences containing an A at position 5 of the Sp1III transcription binding site were associated with significantly higher HIV-1 viral load compared to LTR sequences containing a T at the same position (p=0.0093). Conclusion: Our data clearly show that CSF derived LTR from TBM co-infected individuals exhibit significantly higher transcriptional. Particularly, sequences containing the A5T mutation are significantly associated with higher LTR transcriptional activity and viral load.


Masters Degree. University of KwaZulu-Natal, Durban.