Intracellular immunization against HIV infection with an intracellular antibody that mimics HIV integrase binding to the cellular LEDGF protein

Abstract

Preventing the protein-protein interaction of the cellular chromatin binding protein Lens Epithelium-Derived Growth Factor (LEDGF) and human immunodeficiency virus (HIV) integrase is an important possible strategy for anti-viral treatment for AIDS. We have used Intracellular Antibody Capture technology to isolate a single VH antibody domain that binds to LEDGF. The crystal structure of the LEDGF-VH complex reveals that the single domain antibody mimics the effect of binding of HIV integrase to LEDGF which is crucial for HIV propagation. CD4-expressing T cell lines were constructed to constitutively express the LEDGF-binding VH and these cells showed interference with HIV viral replication, assayed by virus capsid protein p24 production. Therefore, pre-conditioning cells to express antibody fragments confers effective intracellular immunization for preventing chronic viral replication and can be a way to prevent HIV spread in infected patients. This raises the prospect that intracellular immunization strategies that focus on cellular components of viral integrase protein interactions can be used to combat the problems associated with latent HIV virus re-emergence in patients. New genome editing development, such as using CRISPR/cas9, offer the prospect intracellularly immunized T cells in HIV+ patients.

Twenty years of research on the DFS70/LEDGF autoantibody-autoantigen system: many lessons learned but still many questions

“…However, it remains to be determined if these antibodies are capable of binding to DFS70/ LEDGF ensnared within circulating viral particles, and are present in HIV-resistant individuals, potentially serving a protective role. Notably, a lab-generated VH antibody domain that binds the DFS70/LEDGF IBD region interfered with HIV-IN interaction with this domain and viral infectivity in vitro, raising the prospect that antibodies that mimic HIV-IN by targeting the IBD region, such as anti-DFS70/LEDGF autoantibodies, could be used to intracellularly immunize T cells in HIV-positive patients [145].…”

Cloning, purification and structure determination of the HIV integrase-binding domain of lens epithelium-derived growth factor

“…A single VH antibody domain was isolated that binds to LEGDF and blocks the binding of HIV integrase (Bao et al, 2017;Tanaka & Rabbitts, 2010). In the integrase complex, the interface between the integrase and IBD is the surface formed by loops 1-2 and 4-5 (Cherepanov, Ambrosio et al, 2005; PDB entry 2b4j).…”

“…In the integrase complex, the interface between the integrase and IBD is the surface formed by loops 1-2 and 4-5 (Cherepanov, Ambrosio et al, 2005; PDB entry 2b4j). The VH domain also binds IBD, and the crystal structure of the VH-IBD complex shows the same binding site on IBD as the integrase (Bao et al, 2017; PDB entry 5n88). The domain-swapped dimer in the crystal, however, does not present the same binding site as the monomer at loops 1-2 and 4-5, showing that it is not the intracellular form of IBD.…”

Applying Antibodies Inside Cells: Principles and Recent Advances in Neurobiology, Virology and Oncology

“…A way to circumvent this problem could be targeting host proteins that are relevant in the viral life cycle, but do not have high underlying mutation rates like the viral proteins. Protein-protein interaction between a viral and a host protein was blocked by an intrabody as a means to interfere with viral replication and proposed as a potential intracellular immunization for T cells in HIV-positive patients [227]. By expressing an ER intrabody that retained the host cell surface receptor CCR5 in the ER of CD4+ T cells, these cells were protected from viral entry both in vitro and in a mouse model [193].…”