What are proteins that your body produces in respone to foreign matter?

The proteins that your body produces in response to foreign matter are called antibodies. Antibodies are specialised proteins that are designed to recognise and bind to specific antigens, which are molecules that are recognised as foreign by the immune system. When an antigen is detected, the immune system produces antibodies that are specific to that antigen. These antibodies then bind to the antigen and neutralise it, preventing it from causing infection or disease.