Recombinant HIV type 1 gp120 (92RW020) (a.a. 32-494) [His]

Anti-HIV chimeric antigen receptors (CARs) promote direct killing of infected cells, thus offering a therapeutic approach aimed at durable suppression of infection emerging from viral reservoirs. CD4-based CARs represent a favored option, since they target the essential conserved primary receptor binding site on the HIV envelope glycoprotein (Env). We have previously shown that adding a second Env-binding moiety, such as the carbohydrate recognition domain of human mannose-binding lectin (MBL) that recognizes the highly conserved oligomannose patch on gp120, increases CAR potency in an in vitro HIV suppression assay; moreover it reduces the undesired capacity for the CD4 of the CAR molecule to act as an entry receptor, thereby rendering CAR-expressing CD8(+) T cells susceptible to infection. Here, we further improve the bispecific CD4-MBL CAR by adding a third targeting moiety against a distinct conserved Env determinant, i.e. a polypeptide sequence derived from the N-terminus of the HIV coreceptor CCR5. The trispecific CD4-MBL-R5Nt CAR displays enhanced in vitro anti-HIV potency compared to the CD4-MBL CAR, as well as undetectable HIV entry receptor activity. The high anti-HIV potency of the CD4-MBL-R5Nt CAR, coupled with its all-human composition and absence of immunogenic variable regions associated with antibody-based CARs, offer promise for the trispecific construct in therapeutic approaches seeking durable drug-free HIV remission.

We have previously reported a new class of dendrimers with tryptophan (Trp) residues on the surface that show dual antiviral activities against HIV and enterovirus EV71. The prototype compound of this family is a derivative of pentaerythritol with 12 peripheral Trp groups and trivalent spacer arms. Here a novel series of dendrimers with divalent and tetravalent branched arms, instead of the trivalent ones present on the prototype, has been synthesized and its activity against HIV, EV71 and a panel of 16 different viruses and other pathogens has been determined. Convergent or divergent approaches have been used for the synthesis of these compounds. Our findings demonstrate that only compounds with tetravalent branched arms showed the same anti-HIV and anti-EV71 activity of the prototype (low micromolar) and even gain significant antiviral activity against new pathogens such as HSV-2, adenovirus-2, human corona virus and respiratory syncytial virus, being the first members of the Trp dendrimer family that showed activity against those viruses. As the prototype, these compounds also showed low-nanomolar activity against a representative EV71 clinical isolate. Experimental work carried on to determine the mode of action of the most potent IIa, containing tetravalent branched arms, demonstrated that it interacts with the viral envelopes of HIV, EV71 and HSV-2 and thus may prevent virus attachment to the host cell. These results support the interest of this new series of Trp dendrimers and qualify them as useful prototypes for the development of novel inhibitors of viral entry with broad antiviral spectrum.