Anti-HIV-1 gp120 Recombinant Antibody (CH07) (CAT#: MRO-148LC)

Figure 1 HIV-1 pseudovirus neutralization by mAbs CH07 and CH08.

A panel of tier 1 and tier 2 HIV-1 pseudoviruses were tested against mAbs CH07, CH08, 17b, and 412-D in TZM-bl cells. CH07 weakly neutralized a single virus (92TH023.CRF01_AE). In contrast, CH08 neutralized multiple tier 1 and tier 2 viruses in a pattern similar to that of CD4i mAbs 17b and 412-D. A fragment (Fab) of CH08 neutralized with a potency similar to that of the intact mAb, suggesting that the binding site for mAb CH08 was not inaccessible for most of the isolates tested. An additional panel of 13 tier 2 viruses was not neutralized by any mAb tested.

Isolation of HIV-1-Neutralizing Mucosal Monoclonal Antibodies from Human Colostrum

Figure 2 ADCC and virus capture by mAbs CH07 and CH08.

CH07 and CH08 were tested for ADCC activity compared with anti-RSV mAb (Palivizumab) and A32. CH07 did not mediate ADCC, while both A32 and CH08 stimulated granzyme B activity NK effector cells when reacted with infected and gp120-coated targets. Each bar represents the percent of target cells containing granzyme B.

Isolation of HIV-1-Neutralizing Mucosal Monoclonal Antibodies from Human Colostrum

Figure 3 MAb CH07 binding to the HIV-1 Env gp120 C5 region and gp41 fusion domain is sequence specific.

Binding to variant fusion domain and C5 region peptides was measured by SPR. Binding of CH07 to peptides in the C5 region appeared to be most sensitive to a Glu-to-Gln (E to Q) change at position 507. In the fusion domain, hydrophobic amino acid changes at positions 513, 515, and 518 changed binding, suggesting that each substitution altered the conformation of the region in a manner that reduced the ability of CH07 to bind. A consensus sequence peptide containing additional amino acids in the C5 region did not bind, indicating that overlap with C5 sequence was not responsible for the reactivity seen. For both SPR experiments, a gp41 membrane proximal external region peptide was used as a negative control.

Isolation of HIV-1-Neutralizing Mucosal Monoclonal Antibodies from Human Colostrum

Figure 4 Autoreactivity of mAb CH07.

Indirect immunofluorescence staining of HEp-2 cells was strongly positive for mAbs CH07 (A, diffuse nuclear and clumped peripheral staining pattern) and 2F5 (C, diffuse cytoplasmic and nuclear staining pattern); mAbs CH08 (B) and 17b (D) were negative. All images taken for 10 s except CH07 taken for 7 s. Size bars are 25 µm. E. Reactivity of mAb CH07 to 9,000 human proteins in a microarray was assessed, each spot represents binding to a single protein. Pooled human IgG (hIgG) was used to measure background binding.

Isolation of HIV-1-Neutralizing Mucosal Monoclonal Antibodies from Human Colostrum