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.

Anti-TIGIT antibodies and antigen binding fragments thereof that inhibit TIGIT-mediated signalling are provided, together with combinations comprising said antibodies or antigen binding fragments thereof and methods for their use.

Recombinant cell surface capture proteins and detection molecules that are useful for isolating and detecting cells that produce a secreted heterodimeric protein of interest (POI) that has an immunoglobulin CH3 domain and/or substituted CH3 domain are provided. Recombinant cell surface capture proteins and detection molecules that isolate and detect bispecific antibodies are also provided. The invention also provides recombinant antigen-binding proteins that are capable of recognizing and binding to proteins of interest that contain a CH3 domain and/or a modified CH3 domain, such as a CH3 domain with or without amino acid substitutions at H95 and Y96 (IMGT).

The present disclosure provides novel immunoglobulin proteins that bind to a human natriuretic peptide receptor 1 (NPR1) agonist, preferably an anti-NPR1 antibody. In certain embodiments, the proteins of the disclosure comprise at least one immunoglobulin variable domain that binds to an anti-NPR1 antibody. In certain embodiments, the proteins of the disclosure are useful in blocking and/or reversing the effect of an administered anti-NPR1 antibody. In certain embodiments, the antigen-binding proteins are useful for effective management of blood pressure and hemodynamics in humans.

Provided are anti-idiotype antibodies that specifically recognize anti-ROR1 antibody moieties, in particular, anti-ROR1 antibody moieties present in recombinant receptors, including chimeric antigen receptors (CARs). The disclosure further relates to uses of anti-idiotype antibodies for specifically identifying and/or selecting cells expressing such recombinant receptors, such as anti-ROR1 CAR T cells. The disclosure further relates to uses of anti-idiotype antibodies for specifically blocking or activating such cells.

This invention provides, and in certain specific but non-limiting aspects relates to: assays that can be used to predict whether a given ISV will be subject to protein interference as described herein and/or give rise to an (aspecific) signal in such an assay (such as for example in an ADA immunoassay). Such predictive assays could for example be used to test whether a given ISV could have a tendency to give rise to such protein interference and/or such a signal; to select ISV's that are not or less prone to such protein interference or to giving such a signal; as an assay or test that can be used to test whether certain modification(s) to an ISV will (fully or partially) reduce its tendency to give rise to such interference or such a signal; and/or as an assay or test that can be used to guide modification or improvement of an ISV so as to reduce its tendency to give rise to such protein interference or signal; methods for modifying and/or improving ISV's to as to remove or reduce their tendency to give rise to such protein interference or such a signal; modifications that can be introduced into an ISV that remove or reduce its tendency to give rise to such protein interference or such a signal; ISV's that have been specifically selected (for example, using the assay(s) described herein) to have no or low(er)/reduced tendency to give rise to such protein interference or such a signal; modified and/or improved ISV's that have no or a low(er)/reduced tendency to give rise to such protein interference or such a signal.

Isolated antigen binding molecules that specifically bind to an anti-CD19 scFv comprising SEQ ID NO: 1 are provided. The antigen binding molecules can be used in the methods provided herein.

The present disclosure provides methods and compositions that include a polynucleotide that includes nucleic acids that encode an anti-idiotype polypeptide, as well as polypeptides that are encoded by the same, and cells that include and express the polypeptide. Disclosed methods include methods that utilize the anti-idiotype polypeptides as safety switches when they are used in combination with antibodies, include approved biologic antibodies, that include the recognized idiotype. Certain embodiments include anti-idiotype polypeptides and nucleotides encoding the same, that include an internal domain. This internal domain in some embodiments has functional domains that can induce proliferation or cell death upon binding of the anti-idiotype polypeptide by its target antibody.

Isolated antigen binding molecules that specifically bind to an anti-CD19 scFv comprising SEQ ID NO: 1 are provided. The antigen binding molecules can be used in the methods provided herein.

Provided are a monoclonal antibody against CD19 antibody and the application thereof. The monoclonal antibody which targets CD 19 antibody has high specificity and strong affinity. Also provided are a detection reagent with high sensitivity, good accuracy and good specificity for the detection of CAR-T cells and a detection method using the detection reagent, which may directly target an extracellular antigen-binding region on the CAR-T cell.