Preparation of functional IgY that potently neutralizes HIV-1 in TZM-bl Cell line

ABSTRACTAIDS caused by HIV is one of the most serious public health challenges in the world. As we all know, Antiretroviral therapy (ART) is the most effective way to treat AIDS so far, however, forthe reasons of drug resistance, side effects, compliance, economy, limited its using widely. On the other hand, AIDS cannot be completely cured by ART. While the characterization of bnAbs (broadly neutralizing antibodies) in potent HIV neutralization provides considerable insight into HIV curing, it also can be used for passive immunotherapy or combination with ART for HIV-1 treatment. Here we report a novel technology to produce an neutralized activity bnAbs named HIV-1-IgY, which was extracted from the immunized Chicken egg by pNL4-3 virus antigens, and further purified using Water dilution and Salting out method. The specificity, titer and neutralizing activity of HIV-1-IgY was analyzed by Western blotting, ELISA and TZM-bl cell line evaluation system respectively. The results showed that theHIV-1-IgY has high neutralized activity to HIV in vitro; nearly 90% of HIV-1 were neutralized at 1.89μM in TZM-blsystem, which indicated that IgY may be a source of antibodies for AIDS prevention and treatment. Despite its needs to further consider and evaluate neutralized activity in-vivo and the potential mechanisms, Our data showed that we obtained an HIV-1-IgY which could effectively neutralize HIV-l IIIB virus in vitro.

Structural basis of broad HIV neutralization by a vaccine-induced cow antibody

Potent broadly neutralizing antibodies (bnAbs) to HIV have been very challenging to elicit by vaccination in wild-type animals. Here, by x-ray crystallography, cryo–electron microscopy, and site-directed mutagenesis, we structurally and functionally elucidate the mode of binding of a potent bnAb (NC-Cow1) elicited in cows by immunization with the HIV envelope (Env) trimer BG505 SOSIP.664. The exceptionally long (60 residues) third complementarity-determining region of the heavy chain (CDR H3) of NC-Cow1 forms a mini domain (knob) on an extended stalk that navigates through the dense glycan shield on Env to target a small footprint on the gp120 CD4 receptor binding site with no contact of the other CDRs to the rest of the Env trimer. These findings illustrate, in molecular detail, how an unusual vaccine-induced cow bnAb to HIV Env can neutralize with high potency and breadth.

Exploration of HIV-1 fusion peptide–antibody VRC34.01 binding reveals fundamental neutralization sites

VRC34.01 antibody binding to a vulnerable site of HIV envelope glycoprotein (Env), the gp41 fusion peptide, renders robust HIV neutralization, but several critical mutations decrease binding affinity and result in unbinding.

Unexpected synergistic HIV neutralization by a triple microbicide produced in rice endosperm

The transmission of HIV can be prevented by the application of neutralizing monoclonal antibodies and lectins. Traditional recombinant protein manufacturing platforms lack sufficient capacity and are too expensive for developing countries, which suffer the greatest disease burden. Plants offer an inexpensive and scalable alternative manufacturing platform that can produce multiple components in a single plant, which is important because multiple components are required to avoid the rapid emergence of HIV-1 strains resistant to single microbicides. Furthermore, crude extracts can be used directly for prophylaxis to avoid the massive costs of downstream processing and purification. We investigated whether rice could simultaneously produce three functional HIV-neutralizing proteins (the monoclonal antibody 2G12, and the lectins griffithsin and cyanovirin-N). Preliminary in vitro tests showed that the cocktail of three proteins bound to gp120 and achieved HIV-1 neutralization. Remarkably, when we mixed the components with crude extracts of wild-type rice endosperm, we observed enhanced binding to gp120 in vitro and synergistic neutralization when all three components were present. Extracts of transgenic plants expressing all three proteins also showed enhanced in vitro binding to gp120 and synergistic HIV-1 neutralization. Fractionation of the rice extracts suggested that the enhanced gp120 binding was dependent on rice proteins, primarily the globulin fraction. Therefore, the production of HIV-1 microbicides in rice may not only reduce costs compared to traditional platforms but may also provide functional benefits in terms of microbicidal potency.