Herein is reported a method for determining the concentration of a therapeutic antibody in a tissue of an experimental animal to whom the therapeutic antibody had been administered, wherein the interference from residual blood in a tissue sample of the experimental animal, which is used for determining the concentration of the therapeutic antibody in said tissue, is reduced, wherein the concentration of the therapeutic antibody in the tissue of the experimental animal is calculated with the following formula:

[00001]$C_{\mathrm{tmAb},\mathrm{tissue}}=\frac{C_{tmAb,\mathrm{tissue},\det .}}{C_{tis\mathrm{sue},\mathrm{sample}}}-\frac{\frac{C_{refmAb,\mathrm{tissue},\det .}}{C_{tis\mathrm{sue},\mathrm{sample}}}}{C_{refmAb,\mathrm{plasma}.\det .}}*C_{tmAb,\mathrm{plasma},\det }.$

wherein C.sub.tmAb,tissue,det.=obtained by determining the concentration of the therapeutic antibody in the tissue sample of the experimental animal, C.sub.tmAb,plasma,det.=obtained by determining the concentration of the therapeutic antibody in a blood sample of the experimental animal directly prior to taking the tissue sample, C.sub.refmAb,tissue,det.=obtained by determining the concentration of the inert reference antibody in the tissue sample of the experimental animal, C.sub.refmAb,plasma,det.=obtained by determining the concentration of an inert reference antibody in

Aspects of the disclosure relate to antibodies that bind to transferrin receptor (e.g., transferrin receptor 1) and complexes comprising the antibody covalently linked to a molecular payload. Methods of using the antibodies are also provided.

The present disclosure includes a fusion protein, called a “Seldeg”, including a targeting component that specifically binds to a cell surface receptor or other cell surface molecule at near-neutral pH, and an antigen component fused directly or indirectly to the targeting component. The antigen component is configured to specifically bind a target antigen-specific antibody. The present disclosure also includes a method of depleting a target antigen-specific antibody from a patient by administering to the patient a Seldeg having an antigen component configured to specifically bind the target antigen-specific antibody.

Aspects of the disclosure relate to complexes comprising a muscle-targeting agent covalently linked to a molecular payload. In some embodiments, the muscle-targeting agent specifically binds to an internalizing cell surface receptor on muscle cells. In some embodiments, the molecular payload inhibits expression or activity of DUX4. In some embodiments, the molecular payload is an oligonucleotide, such as an antisense oligonucleotide or RNAi oligonucleotide.

Disclosed herein are polynucleic acid molecules, pharmaceutical compositions, and methods for treating facioscapulohumeral muscular dystrophy (FSHD).

Herein are provided bispecific anti-human CD20/human transferrin receptor antibodies and methods of using the same.

It is an object of the present invention to provide an agent for inhibiting iron uptake into cells wherein the agent targets TfR, and an agent for inhibiting the binding between human Tf and human TfR. The present invention provides an agent for inhibiting iron uptake into cells which comprises an antibody which recognizes the amino acids at positions 629 to 633 of a human transferrin receptor.

Herein are provided a method for producing a multispecific antibody comprising the steps of providing a mammalian cell expressing the antibody, transfecting said mammalian cell with an expression vector comprising an expression cassette encoding a polypeptide of the antibody that has a domain crossover, cultivating the transfected cell and recovering the antibody from the cell or the cultivation medium and thereby producing the multispecific antibody.

This disclosure relates to genetically modified animals and cells with humanized light chain immunoglobulin locus and/or humanized heavy chain immunoglobulin locus. In one aspect, the endogenous light chain immunoglobulin locus comprises a limit number of human IGKV genes and human IGKJ genes.

The present disclosure provides anti-transferrin receptor antibodies, compositions comprising the same and methods of their use. This disclosure also provides polynucleotides and vectors encoding the anti-transferrin receptor antibodies and cells comprising the same, methods of making the antibodies, and molecules comprising the antibodies.