Immunoglobulin replacement: Immunisation is the process of making someone resistant to catching a disease which is caused by germs such as viruses or bacteria. Passive immunisation is where the antibodies ( immunoglobulins) which inactivate germs are taken from an animal or another person and put into the body. People who can’t produce enough of their own antibodies to fight off infections may need to have immunoglobulin replacement therapy to keep their immune system working.