Recombinant Human Anti-Streptococcus pneumoniae 23F Antibody scFv Fragment (023.102)

The methylated core disaccharide RGP bound to the paratope of Ab 023.102.

Bryson, S., Thomson, C. A., Risnes, L. F., Dasgupta, S., Smith, K., Schrader, J. W., & Pai, E. F. (2016). Structures of Preferred Human IgV Genes–Based Protective Antibodies Identify How Conserved Residues Contact Diverse Antigens and Assign Source of Specificity to CDR3 Loop Variation. The Journal of Immunology, 196(11), 4723-4730.

A, Left panel, Binding at high concentrations of S.sJ1, which uses the germline sequences of IGHV3-30, IGHJ4, IGKV3-11, and IGKJ1, but with the CDRH3 seen in the hypermutated anti-23F Ab (023.102). Note that binding is observed at far lower concentrations by S.sJ1Ala with a single mutation of Trp to Ala in 96(L) of CDRL3. Right panel, Binding at high concentrations of S.mJ5 using the L chain of the germline Vgene-encoded ancestor of an anti–AD-2S1 Ab and the germline IGKJ5 with a small hydrophilic residue at 96(L) but lacking the additional junctional residue Asp95b(L), whereas, S.sJ5Gly, which has the additional Asp95b(L) binds at lower concentrations to the 23F PPS. No binding of M2.sJ1Ala is observed that has the M2 H chain with the CDRH3 of the germline V-gene–encoded anti–AD-2S1 Abs. Data are the mean 6 SD of triplicate measurements. B, Failure of the germline V-gene–encoded Abs S.sJ1, S.sJ1Ala, S.sJ5Gly, S.mJ5, or M2.sJ1Ala to bind to the 14 PPS (left panel) or 6B PPS (right panel). C, Failure of the germline V-gene–encoded Abs S.sJ1, S.sJ1Ala, S.sJ5Gly, S.mJ5, and M2.sJ1Ala to bind the AD-2S1 peptide. KE5, the hypermutated anti-AD-2S1 mAb, is shown as a positive control. D, A mouse IgM mAb against the human IgG CH3 domain, which forms complexes with S.sJ1 and S.sJ1Ala, increases their avidity for 23F in ELISA. There was no binding observed by the anti–AD-2S1 Ab KE5, either alone or complexed with the IgM. Binding also was not observed with IgM alone (data not shown).

Thomson, C. A., Little, K. Q., Reason, D. C., & Schrader, J. W. (2011). Somatic diversity in CDR3 loops allows single V-genes to encode innate immunological memories for multiple pathogens. The Journal of Immunology, 186(4), 2291-2298.