Selective killing of Kaposi's sarcoma-associated herpesvirus lytically infected cells with a recombinant immunotoxin targeting the viral gpK8.1A envelope glycoprotein

Efficient Infection of a Human B Cell Line with Cell-Free Kaposi's Sarcoma-Associated Herpesvirus

“…For LANA staining, cells were permeabilized in 0.2% Triton X-100 for 10 min and washed 2 times prior to blocking. Cells were blocked in PBS containing 4% bovine serum albumin (BSA) for 30 min and stained in primary specific MAb or control MAb for 1 h at room temperature (for LANA, MAb LN53 [Advanced Biotechnologies]; for K8.1A, MAb 4C3 [67,68]; for gH, MAb15 [69]; mouse IgG was used as a control [BD Pharmingen]). Cells were washed in PBS and probed with anti-mouse IgG secondary antibody conjugated to allophycocyanin (APC; BD Pharmingen) for 1 h. Samples were washed 3 times, pelleted, resuspended in 10 l of PBS, and spread on microscope slides.…”

Antiviral Activity of a Single-Domain Antibody Immunotoxin Binding to Glycoprotein D of Herpes Simplex Virus 2

“…Additionally, the candidate immunotoxins that have been published directed against viruses such as HIV-1 (34, 35), Kaposi's sarcoma-associated herpesvirus (KSHV) (36,37), rabies virus (38), or human cytomegalovirus (39) would also require systemic treatment. To our knowledge, the immunotoxin described here represents the first immunotoxin designed for targeting a pathogen at a mucosal site of infection.…”

“…Daily application of this immunotoxin formulated as a microbicide could help suppress the amount of virus shed by the infected partner and therefore decrease the chance of transmission to the uninfected partner. Immunotoxins targeting KSHV through binding of surface glycoproteins were tested in combination with nucleoside analog antivirals and demonstrated greater efficacy with combination treatment than with immunotoxin treatment alone (36,37). R33ExoA treatment in combination with oral antiviral drugs could potentially maintain the amount of virus shed below the level estimated to be needed for transmission (55).…”

Structural Complementation of the Catalytic Domain of Pseudomonas Exotoxin A

“…25–31 Replacement of the native receptor-binding domains with other ligands, such as monoclonal antibodies, results in toxin fusions with redirected specificity for other cell-surface receptors. 45,46 Currently, targeting is typically limited to single receptors such as CD22, 47 the IL-2 48 and IL-13α2 receptors, 49 viral envelope glycoproteins, 50,51 and the EGFR family of receptor tyrosine kinases. 52–56 Alternatively, targeting can be achieved with toxin transgenes whose expression is controlled by a tissue- or disease-specific promoter.…”