Antiserum is a blood serum that contains antibodies that are specific to a particular antigen or pathogen. It is produced by injecting a person or animal with a particular antigen, such as a virus or bacteria, which stimulates the immune system to produce specific antibodies against that pathogen. The antibodies are then collected from the blood serum and purified to create the antiserum. Anti-tetanus immunoglobulin/tetanus immune globulin/ tetanus antitoxin, is a medication made up of antibodies against the tetanus toxin Human rabies immune globulin (HRIG) is administered only once, at the beginning of anti-rabies prophylaxis, to previously unvaccinated persons. This provide immediate antibodies until the body produces antibodies of its own.