Detection and activation of HIV broadly neutralizing antibody precursor B cells using anti-idiotypes

Bancroft, Tara; DeBuysscher, Blair L.; Weidle, Connor; Schwartz, Allison; Wall, Abigail; Gray, Matthew D.; Feng, Junli; Steach, Holly R.; Fitzpatrick, Kristin S.; Gewe, Mesfin M.; Skog, Patrick D.; Doyle-Cooper, Colleen; Ota, Takayuki; Strong, Roland K.; Nemazee, David; Pancera, Marie; Stamatatos, Leonidas; McGuire, Andrew T.; Taylor, Justin J.

We next examined the unique heavy chain CDRH3 regions used by IB2 + V H 1-3 + BCRs in search of further similarity to iglb12. Since we were only able to detect 10 IB3 + V H 1-3 + BCRs in this dataset, these BCRs were not included in this analysis. The crystal structure of IB2 bound to iglb12 revealed that 44% of the BSA was contributed by the CDRH3 of iglb12 (Fig. 2 J) . Nearly all of the CDRH3 BSA, 82% (i.e., 36% of the total BSA), is focused on the portion encoded by D H 2-21 ( Fig. 4 E) . However, only 3.6% of IB2 + V H 1-3 + BCRs used D H 2-21, which was not different from control V H 1-3 + BCRs (Fig. 4 F) . Of the CDRH3 regions in IB2 + V H 1-3 + BCRs, the two most similar to iglb12 CDRH3 only displayed 50% amino acid identity ( Fig. 4 G) .