What Is Passive Immunity?

Passive immunity is the specific immune ability obtained by the body passively receiving antibodies, sensitized lymphocytes or their products. It is different from the auto-immunity that is actively generated. It is characterized by fast effects and does not need to pass through the incubation period. Once input, immunity can be obtained immediately. But the maintenance time is short.

Passive immunity

Passive immunity is when the body passively receives antibodies,

According to the method of obtaining, it can be divided into

Commonly used biological products for artificial passive immunity include antitoxin, placental globulin, antibacterial serum, and immunomodulators.

Passive immune antitoxin

Antitoxin is to inoculate experimental animals (usually horses) multiple times with toxoids obtained from pathogenic microorganisms. After these animals produce a large amount of antibodies against the toxoid, the animal's blood is used as a raw material to extract antibodies from serum This antibody is called antitoxin. Diphtheria antitoxin, tetanus and botulinum antitoxin are such biological products. At present, diphtheria and tetanus antitoxins are made from horses in China. Therefore, skin tests should be performed when using this kind of antitoxin to prevent the occurrence of type I hypersensitivity reactions.

Placental globulin

Placental globulin is extracted from the placenta and umbilical cord blood of healthy mothers. It mainly contains gamma globulin. The gamma globulin extracted from placental globulin is called placental gamma globulin, and if it is extracted from the serum of healthy adults, it is called human serum gamma globulin. Because most adults have experienced common recessive infections of gastrointestinal and respiratory tract pathogens, and some have suffered from certain infectious diseases, their serum (or placenta) may contain antibodies to multiple pathogens. Placental globulin or gamma globulin is mainly used for emergency prevention of toxins such as measles, hepatitis A and polio. Because such preparations are not specifically prepared for specific antibodies against a specific pathogen, their immune effect is not as good as specialized specific immunoglobulin antibody products.

Passive immune antisera

Some pathogenic microorganisms, especially viruses, that we have not obtained virogen, can be directly inoculated with experimental animals. After the animals have acquired immunity, the serum containing antibodies is refined and made into products. For example, anti-rabies serum and anti-Japanese encephalitis serum.

Passive immune immunomodulator

This is a large class of biological products capable of enhancing, promoting and regulating immune function. Immune modulators have a small biological effect on sound immune function, but have good therapeutic effect on tumor patients, AIDS patients and some individuals with weak immune function. These include transfer factors, interleukins, thymosins, interferons, and more.