Immunology and Allergology >>>> Immune sera

Immune sera.

The discovery by scientists of immunoglobulins made it possible to invent important drugs against many dangerous pandemic diseases. Since immunoglobulins are released by B-lymphocytes into the bloodstream at the moment a foreign gene is detected, it became possible to extract immunoglobulins from the body of an infected object (human or animal) by obtaining blood serum (immune serum) containing the required immunoglobulins (usually immunoglobulins of the IgG group). Introduced into the blood of another organism, such serums create passive immunity that can immediately neutralize pathogens or their toxins.

By their nature, immune sera are homologous, that is, obtained from human blood (a donor who has already had this disease or has been specially immunized repeatedly), and heterologous - obtained from the blood of repeatedly immunized animals (most often from the blood of horses).

The difference between the effect of heterologous and homologous serum lies in the period of time during which the immunoglobulins introduced with the serum are excreted from the body (decay naturally or under the influence of newly formed antibodies to them). In the case of heterologous sera, this period is one to two weeks, and in the case of homologous sera, it is four to five weeks, that is, a longer effect of resistance to infection.

Depending on what exactly the action of the immunoglobulin contained in the serum will be directed to, the immune sera are divided into:

antitoxic (against botulism, tetanus, diphtheria, gas gangrene),
antimicrobial (antiviral and antibacterial),
mixed action (against bacteria and their toxins).

Antiviral sera include immunoglobulins against influenza, measles, rabies infection (rabies).

Antibacterial sera contain antibodies to bacteria - causative agents of plague, whooping cough, typhoid fever, dysentery.

According to the target action of the serum, the following can be used:

For prophylactic purposes in case of suspicion of the penetration of an infectious agent into the body (for example, upon contact with an infected object - a person or an animal).
For the treatment of infection in the presence of obvious clinical signs of the disease. In such cases, sera containing targeted immunoglobulins are used, which are obtained from the blood of volunteers - donors who have undergone immunization against a certain infection. These sera contain elevated concentrations of specific antibodies. Sera with targeted immunoglobulins are designed to treat influenza, smallpox, staphylococcus, tick-borne encephalitis, rabies, and tetanus.
For diagnostics - identification of microorganisms or exotoxins with the setting of the necessary serological reactions (agglutination, complement binding, precipitation, neutralization, and others). Diagnostic sera are obtained by immunizing other animals (rabbits, rats), and such sera are unsuitable for use in humans, since they cause sensitization of the body and threaten death.

Immune sera are an aqueous solution of the protein globulin fraction (gamma and beta globulins). Some immune sera undergo a high degree of purification of the gamma globulin fraction of the protein and are called gamma globulins. Many gamma globulin preparations contain antibodies not to one type of pathogenic microorganism, but to several pathogens simultaneously and have a combined effect.

Modern methods of preparation of immune sera exclude the presence of pathogens in the serum, but do not completely exclude reactogenic proteins (causing side effects), which can cause allergic reactions of varying severity and other complications. It is for this reason that immunoglobulin preparations are injected intramuscularly, subcutaneously or irrigate the mucous membrane with them. Those groups of immunoglobulins that are designed for intramuscular administration are subjected to additional purification to reduce the degree of their reactogenicity.