MAbs. 2013 Nov 20;6(1). [Epub ahead of print]
Generation of "LYmph Node Derived Antibody Libraries" (LYNDAL) for selecting fully human antiviral antibody fragments with therapeutic potential.
Diebolder P, Keller A, Haase S, Schlegelmilch A, Kiefer JD, Karimi T, Weber T, Moldenhauer G, Kehm R, Eis-Hübinger AM, Jäger D, Federspil PA, Herold-Mende C, Dyckhoff G, Kontermann RE, Arndt MA, Krauss J.
The development of efficient strategies for generating fully human monoclonal antibodies with unique functional properties that are exploitable as tailored therapeutic interventions remains a major challenge in the antibody technology field. Here, we present a methodology for recovering such antibodies from antigen-encountered human B cell repertoires. As the source for variable antibody genes, we cloned immunoglobulin G (IgG)-derived B cell repertoires from lymph nodes of 20 individuals undergoing surgery for head and neck diseases. Sequence analysis of unselected "LYmph Node Derived Antibody Libraries" (LYNDAL) revealed a naturally occurring distribution pattern of rearranged antibody sequences, representing all known variable gene families and most functional germline sequences. To demonstrate the feasibility for selecting antibodies with therapeutic potential from these repertoires, seven LYNDAL from donors with high serum titers against herpes simplex virus (HSV) were panned on recombinant glycoprotein B of HSV-1. Screening for specific binders delivered 34 single-chain variable fragments (scFvs) with unique sequences. Sequence analysis revealed extensive somatic hypermutation of enriched clones as a result of affinity maturation. Binding of scFvs to common glycoprotein B variants from HSV-1 and HSV-2 strains was highly specific, and the majority of analyzed antibody fragments bound to the target antigen with nanomolar affinity. From eight scFvs with HSV-neutralizing capacity in vitro, the most potent antibody neutralized 50% HSV-2 at 4.5 nM as a dimeric (scFv) 2. We anticipate our approach to be useful for recovering fully human antiviral antibodies with therapeutic potential.
Hum Vaccin Immunother. 2014 Feb 4;10(4). [Epub ahead of print]
Characterization of the biological anti-staphylococcal functionality of hUK-66 IgG1, a humanized monoclonal antibody as substantial component for an immunotherapeutic approach.
Oesterreich B, Lorenz B, Schmitter T, Kontermann R, Zenn M, Zimmermann B, Haake M, Lorenz U, Ohlsen K.
Multi-antigen immunotherapy approaches against Staphylococcus aureus are expected to have the best chance of clinical success when used in combinatorial therapy, potentially incorporating opsonic killing of bacteria and toxin neutralization. We recently reported the development of a murine monoclonal antibody specific for the immunodominant staphylococcal antigen A (IsaA), which showed highly efficient staphylococcal killing in experimental infection models of S. aureus. If IsaA-specific antibodies are to be used as a component of combination therapy in humans, the binding specificity and biological activity of the humanized variant must be preserved. Here, we describe the functional characterization of a humanized monoclonal IgG1 variant designated, hUK-66. The humanized antibody showed comparable binding kinetics to those of its murine parent, and recognized the target antigen IsaA on the surface of clinically relevant S. aureus lineages. Furthermore, hUK-66 enhances the killing of S. aureus in whole blood (a physiological environment) samples from healthy subjects and patients prone to staphylococcal infections such as diabetes and dialysis patients, and patients with generalized artery occlusive disease indicating no interference with already present natural antibodies. Taken together, these data indicate that hUK-66 mediates bacterial killing even in high risk patients and thus, could play a role for immunotherapy strategies to combat severe S. aureus infections.