A Novel Class of Anti-HIV Agents with Multiple Copies of Enfuvirtide Enhances Inhibition of Viral Replication and Cellular Transmission In Vitro

Abstract

We constructed novel HIV-1 fusion inhibitors that may overcome the current limitations of enfuvirtide, the first such therapeutic in this class. The three prototypes generated by the Dock-and-Lock (DNL) technology to comprise four copies of enfuvirtide tethered site-specifically to the Fc end of different humanized monoclonal antibodies potently neutralize primary isolates (both R5-tropic and X4-tropic), as well as T-cell-adapted strains of HIV-1 in vitro. All three prototypes show EC 50 values in the subnanomolar range, which are 10- to 100-fold lower than enfuvirtide and attainable whether or not the constitutive antibody targets HIV-1. The potential of such conjugates to purge latently infected cells was also demonstrated in a cell-to-cell viral inhibition assay by measuring their efficacy to inhibit the spread of HIV-1 LAI from infected human peripheral blood mononuclear cells to Jurkat T cells over a period of 30 days following viral activation with 100 nM SAHA (suberoylanilide hydroxamic acid). The IgG-like half-life was not significantly different from that of the parental antibody, as shown by the mean serum concentration of one prototype in mice at 72 h. These encouraging results provide a rationale to develop further novel anti-HIV agents by coupling additional antibodies of interest with alternative HIV-inhibitors via recombinantly-produced, self-assembling, modules.

A new class of bispecific antibodies to redirect T cells for cancer immunotherapy

“…Since its inception in 2005, the DNL method, by combining DDD2-and AD2 modules derived from assorted classes of molecules that encompass IgG, [38][39][40][41] Fab, 34,42,43 cytokines, [44][45][46] polyethylene glycols, 47 and enfuvirtide, 48 has been used to produce more than 100 different complexes with potential applications for targeted therapies of malignant, autoimmune, and infectious diseases. The generation of a functional Okt3-scFv-AD2 and the demonstration of the in vitro and in vivo activities of various (X)-3s to kill target tumor cells via T cells, as described in this study, expands the applications of the DNL repertoire to now include scFv as a viable building block for future exploration.…”

Short-term HIV-1 treatment interruption is associated with dysregulated TLR-stimuli responsiveness

“…In order to mimic reactivated HIV replication, an in vitro model making use of HDACi has, for example, shown that externally working antiviral agents, such as antibody conjugated enfuvirtide, could inhibit further spreading of the majority of re-activated HIV. 40 In the present paper, dysregulation of TLR-triggered IL-12 and IFN-α occurred in concert with increased viral loads and may, in addition to the TI, have contributed to the viral re-activation. Since we previously demonstrated that new cellular immune responses to HIV antigens occurred during the HIV-DNA vaccination schedule, 22 it disappointingly appears that the immune responses here induced in vivo cannot considerably dampen the reactivation of HIV.…”

Immunization with HIV-1 envelope T20-encoding DNA vaccines elicits cross-clade neutralizing antibody responses

“…Our attempts to improve antibody induction to the HIV virion and infected cell surface were directed at a conserved amino acid stretch that also has potent anti-retroviral effects. 4,32 The T20 peptide is located at the gp41 transmembrane protein which is important for HIV-1 fusion. This part of the virion is available for direct immune attack during just a short period of the viral life cycle, and antibodies may have to utilize cell/virion lipid membranes for access to bind and neutralize.…”

“…We have previously demonstrated that T20 multimerization via DOCK-AND-LOCK®-mediated conjugation to an IgG-carrier increases anti-retroviral activity 10–100-fold. 4 The property of site-specific binding of an antigen is also useful to induce immune responses, since complexes of antigens usually improve immunogenicity.…”