Efetaal

27725930

Eliminating virally infected cells is an essential component of any HIV eradication strategy. Radioimmunotherapy (RIT), a clinically established method for killing cells using radiolabeled antibodies, was recently applied to target HIV-1 gp41 antigen expressed on the surface of infected cells. Since gp41 expression by infected cells is likely downregulated in patients on antiretroviral therapy (ART), we evaluated the ability of RIT to kill ART-treated infected cells using both in vitro models and lymphocytes isolated from HIV-infected subjects. Human peripheral blood mononuclear cells (PBMCs) were infected with HIV and cultured in the presence of two clinically relevant ART combinations. Scatchard analysis of the 2556 human monoclonal antibody to HIV gp41 binding to the infected and ART-treated cells demonstrated sufficient residual expression of gp41 on the cell surface to warrant subsequent RIT. This is the first time the quantification of gp41 post-ART is being reported. Cells were then treated with Bismuth-213-labeled 2556 antibody. Cell survival was quantified by Trypan blue and residual viremia by p24 ELISA. Cell surface gp41 expression was assessed by Scatchard analysis. The experiments were repeated using PBMCs isolated from blood specimens obtained from 15 HIV-infected individuals: 10 on ART and 5 ART-naïve. We found that 213Bi-2556 killed ART-treated infected PBMCs and reduced viral production to undetectable levels. ART and RIT co-treatment was more effective at reducing viral load in vitro than either therapy alone, indicating that gp41 expression under ART was sufficient to allow 213Bi-2556 to deliver cytocidal doses of radiation to infected cells. This study provides proof of concept that 213Bi-2556 may represent an innovative and effective targeting method for killing HIV-infected cells treated with ART and supports continued development of 213Bi-2556 for co-administration with ART toward an HIV eradication strategy.

antiretroviral therapy, HIV, radioimmunotherapy, gp41, bismuth-213, patients

Combination of Antiretroviral Drugs and Radioimmunotherapy Specifically Kills Infected Cells from HIV-Infected Individuals

Dina Tsukrov,1 Alicia McFarren,1 Alfred Morgenstern,2 Frank Bruchertseifer,2 Eugene Dolce,1 Miroslaw K. Gorny,3 Susan Zolla-Pazner,3,4 Joan W. Berman,1 Ellie Schoenbaum,1 Barry S. Zingman,1 Arturo Casadevall,1 and Ekaterina Dadachova1,*

2016 Sep 26

26595540

Objective
Many HIV patients on cART exhibit HIV-associated neurocognitive disorders because the brain becomes a viral reservoir. There is a need for therapeutics that can enter the CNS and eradicate the virus.

Design
Radiolabeled human mAb 2556 to HIV gp41 selectively kills HIV-infected cells in vivo and in vitro. Here we tested the ability of 213Bi-2556 to cross a tissue culture model of the human BBB and kill HIV-infected PBMCs and monocytes on the CNS side of the barrier.

Methods
2556 mAb isoelectric point (pI) was determined with IEF. The ability of radiolabeled 2556 to penetrate through the barrier was studied by adding it to the upper chamber of the barriers and its penetration into the CNS side was followed for 5 hrs. To assess the ability of 213Bi-2556 to kill the HIV-infected cells on the CNS side of barrier, the HIV-infected and uninfected PBMCs and monocytes were allowed to transmigrate across the barriers overnight followed by application of 213Bi-2556 or control mAb 213Bi-1418 to the top of the barrier. Killing of cells was measured by TUNEL and Trypan blue assays. The barriers were examined by confocal microscopy for overt damage.

Results
The pI of 213Bi-2556 was 9.6 enabling its penetration through the barrier by transcytosis. 213Bi-2556 killed significantly more transmigrated HIV-infected cells in comparison to 213Bi-1418 and uninfected cells. No overt damage to barriers was observed.

Conclusions
We demonstrated that 213Bi-2556 mAb crossed an in vitro human BBB and specifically killed transmigrated HIV-infected PBMCs and monocytes without overt damage to the barrier.

neuroAIDS, HAND, in vitro human blood brain barrier model, HIV-infected human PBMCs, monocytes, radioimmunotherapy, 213-Bismuth

A fully human antibody to gp41 selectively eliminates HIV-infected cells that transmigrated across a model human blood brain barrier

Alicia McFARREN,1 Lillie LOPEZ,1 Dionna W. WILLIAMS,1 Mike VEENSTRA,1 Ruth A. BRYAN,1 Aliza GOLDSMITH,1 Alfred MORGENSTERN,2 Frank BRUCHERTSEIFER,2 Susan ZOLLA-PAZNER,3,4 Miroslaw K. GORNY,3 Eliseo A. EUGENIN,5 Joan W. BERMAN,1 and Ekaterina DADACHOVA1,*

2017 Feb 20.