Reducing imunogenicities of immunoglobulins by framework-patching

Abstract

Framework (FR)-patching is a novel approach to modify immunoglobulin for reducing potential immunogenicity without significant alterations in specificity and affinity. Unlike previous described methods of humanization, which graft CDRs from a donor onto the frameworks of a single acceptor immunoglobulin, we patch segments of framework (FR1, FR2, FR3 and FR4), or FRs, to replace the corresponding FRs of the parent immunoglobulin. Free assortment of these FRs from different immunoglobulins and from different species can be mixed and matched into forming the final immunoglobulin chain. A set of criteria in the choice of these FRs to minimize or eliminate the need to reintroduce framework amino acids from the parent immunoglobulin for patching is described. The approach gives greater flexibility in the choice of framework sequences, minimizes the need to include parent framework amino acids, and, most importantly, reduces the chances of creating new T- and B-cell epitopes in the resultant immunoglobulin.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuing application of U.S. application Ser. No. 09 / 892,613, filed Jun. 27, 2001, the contents of which are incorporated herein in their entirety.[0002] Throughout this application, various references are referred to within parenthesis. Disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains. FIELD OF THE INVENTION [0003] The present invention relates to novel methods in re-engineering, or reshaping antibodies with clinical indications (both therapeutic and diagnostic). The method combines the use of recombinant technology and, stepwise and systemic approaches in re-designing antibody sequences. The invention particularly provides for antibodies which are modified to be less immunogenic than the unmodified counterpart when used in vivo. BACKGROUND OF THE INVENTION [0004] Monoclona...

AI Technical Summary

Benefits of technology

The present invention provides a novel method for re-engineering immunoglobulins by replacing certain parts of the framework sequences with those of other immunoglobulins to reduce or eliminate immunogenicity without sacrificing binding affinity. The method involves dividing the framework sequences into subregions and comparing them to human or primate immunoglobulin sequences to select the most homologous sequences for patching. The patched immunoglobulins will have reduced or eliminated immunogenicity in humans and will be suitable for treating various diseases. The invention offers a flexible and easy-to-use method for generating immunoglobulins with reduced or eliminated immunogenicities.

Problems solved by technology

However, the concept of magic bullet took more than 25 years to realize, because there were problems associated with the use of monoclonal antibodies.

One of the main problems stems from the original source of most monoclonal antibodies, which are of rodent and murine origin.

However, direct replacement of framework sequences without further modifications can result in the loss of affinity for the antigen, sometimes as much as 10-fold or more (Jones et al., Nature, 321:522-525, 1986; Verhoyen et al., Science, 239:1534-1536, 1988).

Moreover, the identification of the proper framework amino acids to be replaced can sometimes be difficult, further reducing the chances of success in humanization without significant impacts on the specificity and affinity of the humanized antibody.

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