Disclosed herein are anti-IgE antibodies having low binding affinity to human IgE and compositions and methods thereof. In some embodiments, the present invention provides a composition comprising one or more humanized low affinity anti-IgE antibodies (hLAAIGEs) and a pharmaceutically acceptable carrier. In some embodiments, the present invention provides a method of treating a subject for an IgE-mediated disorder, which comprises administering to the subject one or more hLAAIGEs or a composition thereof. In some embodiments, the IgE-mediated disorder is an allergic reaction.

The present invention discloses the generation of novel variants of Fc domains, including those found in antibodies, Fc fusions, and immuno-adhesions, which have an increased binding to the FcRn receptor and/or increased serum half-life.

Provided herein are single-chain polypeptides and multi-chain polypeptides that bind specifically to CD3 epsilon (CD3ε). Also provided herein are anti-idiotypic antibodies that bind specifically to any of the antigen-binding domains described herein.

The present invention relates to methods, kits and a test strip for detecting gut barrier dysfunction and/or cirrhosis in a subject. In addition, a method of treating a subject with gut barrier dysfunction and/or cirrhosis is provided.

In alternative embodiments, provided are chimeric immunogens or antigens, and methods for making and using them, including methods for making and obtaining polyclonal antibodies specific for selected epitopes. In alternative embodiments, provided are methods for generating an epitope-specific antibody response in a rabbit, wherein the immune response comprises generation of rabbit antibodies specifically against (or that specifically bind to) at least one human epitope, and the method comprises administering to a rabbit a sufficient amount of a chimeric or recombinant polypeptide to generate the epitope-specific antibody response. In alternative embodiments, provided are chimeric or recombinant polypeptides comprising: a ferritin polypeptide having conjugated or attached thereto by or via a substantially non-immunogenic linker an immunogenic peptide or polypeptide.

Isolated human monoclonal antibodies which bind to IL-8 (e.g., human IL-8) are disclosed. The human antibodies can be produced in a hybridoma, transfectoma or in a non-human transgenic animal, e.g., a transgenic mouse, capable of producing multiple isotypes of human monoclonal antibodies by undergoing V-D-J recombination and isotype switching. Also disclosed are pharmaceutical compositions comprising the human antibodies, non-human transgenic animals, hybridomas, and transfectomas which produce the human antibodies, and therapeutic and diagnostic methods for using the human antibodies.

Provided is an antibody that has a high binding activity to membrane-bound IgM on the surface of B cells and exhibits a growth inhibition effect on the B cells, even in the presence of soluble IgM in blood. A bispecific antibody, which binds to IgM and a B cell surface antigen.

Provided is an antibody that has a high binding activity to membrane-bound IgM on the surface of B cells and exhibits a growth inhibition effect on the B cells, even in the presence of soluble IgM in blood. A bispecific antibody, which binds to IgM and a B cell surface antigen.

In certain aspects, the disclosure relates to anti-idiotype antibodies and antigen-binding portions thereof that specifically bind a CD9B441 containing protein, e.g., an antibody or antigen-binding portions thereof. In some aspects, the anti-idiotype antibodies and antigen-binding portions of the present disclosure can be used in methods to detect and quantify cells expressing chimeric antigen receptors that include CD9B441.

The invention provides improved methods for detecting anti-BCMA CAR expression on T cells. The invention generally provides antibodies and antigen binding fragments thereof, conjugates thereof, and methods of using the same to detect, determine, or measure CAR T cells and/or CAR expression on one or more T cells.