ZBiotech’s N-glycan microarray helps scientists determine glycan binding profiles of HIV-1 broadly neutralizing antibodies.

Munir Alam and colleagues have designed a synthetic immunogen that mimics the envelope epitopes of the HIV-1 virus to induce broadly neutralizing antibodies (bnAbs). Vaccine-induced bnAbs would grant glycan-targeted immunity against HIV-1. One of the prominent targets of bnAbs is the glycopeptides on the base of the viral envelope within the third variable loop (V3). When rhesus macaques were immunized with V3-Man9, they started producing bnAbs that recognize the envelope V3 region. Several bnAbs (PGT128, VRC41.01, VRC41.02, and DH563) were isolated from HIV-1 infected individuals. Using our N-glycan Microarray, researchers determined the glycan-binding specificities of these bnAbs.

Various synthetic N-glycans were printed in triplicates onto the microarray substrates coated with our patented surface chemistries for the N-glycan microarray. Each subarray was blocked with the glycan-blocking buffer, after which the desired antibodies, diluted in the glycan array assay buffer, were further incubated on the subarrays. Antibodies bound to glycans were detected with a Cy3-conjugated anti-IgG human antibody with the outcoming fluorescent response. This assay revealed that VRC41.01 and PGT128 preferably bind to high-mannose N-glycans, like Man7, Man8, and Man9, in a similar manner. Lower-order mannose glycans weakly interact with VRC41.01 while having no binding to PGT128. Antibodies DH563 and VRC41.02 did not bind to any of the tested glycans on the microarray.

Our N-glycan microarray can be very useful in determining the strength of interactions between synthetically produced glycans and glycan-targeted antibodies. The strength of interactions and the preferability in binding, or the glycan binding profile, can be easily determined using the N-glycan microarray.