Mice having a restricted immunoglobulin heavy chain locus are provided, wherein the locus is characterized by a single polymorphic human V.sub.H gene segment, a plurality of human D.sub.H gene segments and a plurality of J.sub.H gene segments. Methods for making antibody sequences that bind an antigen (e.g., a viral antigen) are provided, comprising immunizing a mouse with an antigen of interest, wherein the mouse comprises a single human V.sub.H gene segment, a plurality of human D.sub.H gene segments and a plurality of J.sub.H gene segments, at the endogenous immunoglobulin heavy chain locus.

Mice, embryos, cells, and tissues having a restricted immunoglobulin heavy chain locus and an ectopic sequence encoding one or more ADAM6 proteins are provided. In various embodiments, mice are described that have humanized endogenous immunoglobulin heavy chain loci and are capable of expressing an ADAM6 protein or ortholog or homolog or functional fragment thereof that is functional in a male mouse. Mice, embryos, cells, and tissues having an immunoglobulin heavy chain locus characterized by a single human V.sub.H gene segment, a plurality of human D.sub.H gene segments and a plurality of human J.sub.H gene segments and capable expressing an ADAM6 protein or ortholog or homolog or functional fragment thereof are also provided.

The invention provides non-human cells and mammals having a genome encoding chimeric antibodies and methods of producing transgenic cells and mammals. Certain aspects of the invention include chimeric antibodies, humanized antibodies, pharmaceutical compositions and kits. Certain aspects of the invention also relate to diagnostic and treatment methods using the antibodies of the invention.

The present invention provides pharmaceutical compositions comprising second-generation molecules that are superior than TOCILIZUMAB, by altering the amino acid sequences of the variable and constant regions of TOCILIZUMAB, which is a humanized anti-IL-6 receptor IgG1 antibody, to enhance the antigen-neutralizing ability and increase the pharmacokinetics, so that the therapeutic effect is exerted with a less frequency of administration, and the immunogenicity, safety and physicochemical properties (stability and homogeneity) are improved. The present invention also provides methods for producing these pharmaceutical compositions.

The present inventors have successfully generated second-generation molecules that are superior to TOCILIZUMAB by appropriately combining amino acid sequence alterations in the CDR domains, variable regions, and constant regions.

Provided herein are antibodies and antigen-binding fragments thereof with low or no immunogenicity in humans and optionally with desirable manufacturing properties. Also provided are compositions comprising such antibodies or antigen-binding fragments, methods of using such antibodies, and methods for making such antibodies.

Provided herein are immunomodulatory proteins comprising ICOSL variants and nucleic acids encoding such proteins. The immunomodulatory proteins provide therapeutic utility for a variety of immunological and oncological conditions. Compositions and methods for making and using such proteins are provided.

The present invention provides pharmaceutical compositions comprising second-generation molecules that are superior than TOCILIZUMAB, by altering the amino acid sequences of the variable and constant regions of TOCILIZUMAB, which is a humanized anti-IL-6 receptor IgG1 antibody, to enhance the antigen-neutralizing ability and increase the pharmacokinetics, so that the therapeutic effect is exerted with a less frequency of administration, and the immunogenicity, safety and physicochemical properties (stability and homogeneity) are improved. The present invention also provides methods for producing these pharmaceutical compositions.

The present inventors have successfully generated second-generation molecules that are superior to TOCILIZUMAB by appropriately combining amino acid sequence alterations in the CDR domains, variable regions, and constant regions.

The disclosure provides a method for generation of humanized full length antibodies in mammalian cells. A library of humanized variants is provided with high, validated human framework diversity without requiring back-mutations to retain original affinity. Synthetic CDR encoding fragment libraries derived from a template antibody are ligated to human framework region encoding fragments from a human framework pool limited only to germline sequences from a functionally expressed antibodies. The vector comprises a nucleic acid sequence encoding HC framework region 4. No CDR grafting or phage display is required.

Antibodies comprising unpaired variable domains, e.g., heavy chain variable (VH) domains, for binding antigen. Antibody comprising two immunoglobulin (Ig) chains, wherein a first Ig chain comprises a variable domain and a constant domain, and a second Ig chain comprises a constant domain, wherein the second Ig chain lacks a variable domain, leaving the variable domain of the first Ig chain unpaired. The antibody may comprise two Ig heavy chains and two Ig light chains, each heavy chain comprising a VH domain and a constant region comprising a CH1 domain, and each light chain comprising a CL domain, wherein one or both light chains lack a VL domain, thereby leaving one or both VH domains unpaired. Non-human animals (e.g., mice) engineered to produce antibodies having unpaired VH domains, involving deletion of sequence coding for light chain variable (VL) domains. Use of unpaired VH domains to generate antigen-binding molecules.

Described herein are methods and compositions relating to anti-CHI3L1 antibodies, antibody reagents, and antigen-binding fragments thereof which display superior properties, e.g., high sensitivity, high specificity, high binding affinity, neutralization activity ex vivo and in vivo (e.g., blocks CHI3L1-induced MARK and AKT signaling) Methods of treatment, e.g., of treating fibrosis by administering the compounds described herein are also provided.