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.

Deletion and anergy in transgenic mice expressing iglb12 heavy chain To assess whether the autoreactivity detected in the HEp-2 assay resulted in functional consequences in vivo, we generated a transgenic mouse in which all B cells expressed the iglb12 heavy chain. Previous work has demonstrated that B cells from BCR knock-in mice expressing 4E10, but not mature b12, are deleted from the repertoire as a consequence of autoreactivity Ota et al., 2013) . We found that iglb12 heavy chain transgenic mice displayed a three-to fourfold reduction in the number of CD19 + B220 + CD93 − CD3 − F4/80 − Gr-1 − mature B cells in the spleen compared with WT mice or mice expressing a control inferred germline heavy chain generated using the same knock-in strategy Fig. 6, A and B) . Deletion could be traced back to the immature stage in the bone marrow, where iglb12 heavy chain transgenic mice contained approximately twofold fewer CD19 + B220 + CD93 + IgM + CD3 − F4/ 80 − Gr-1 − mature B cells compared with both WT and control transgenic animals (Fig. 6, C and D) . Together, the data indicate that a significant portion of murine B cells expressing an iglb12 heavy chain are deleted in the bone marrow.