An antigen binding protein is a type of protein that is specifically engineered or selected to bind to a particular antigen. These proteins can be antibodies, antibody fragments, or other types of protein scaffolds that have been designed or modified to have high affinity and specificity for a target antigen. Antigen binding proteins are widely used in research, diagnostics, and therapeutic applications. They enable the detection and identification of specific antigens, facilitate immune responses, and can be engineered to deliver therapeutic agents to targeted cells or tissues.