One-domain CD4 Fused to Human Anti-CD16 Antibody Domain Mediates Effective Killing of HIV-1-Infected Cells

Bispecific killer cells engagers (BiKEs) which can bind to natural killer (NK) cells through the activating receptor CD16A and guide them to cells expressing the HIV-1 envelope glycoprotein (Env) are a promising new weapon for elimination of infected cells and eradication of the virus. Here we report the design, generation and characterization of BiKEs which consist of CD16A binding human antibody domains fused through a flexible linker to an engineered one-domain soluble human CD4. In presence of cells expressing HIV-1 envelope glycoproteins (Envs), these BiKEs activated specifically CD16A-expressing Jurkat T cells, degranulated NK cells, induced cytokine production and killed Env-expressing cells. They also effectively mediated killing of chronically and acutely HIV-1 infected T cells by human peripheral blood mononuclear cells. The presumed ability of these CD4-based BiKEs to bind all HIV-1 isolates, their small size and fully human origin, combined with high efficacy suggest their potential for HIV-1 eradication.