Passive immunization

Administration of antibodies against an antigen. These are either donor-derived or genetically engineered. They predominantly belong to the IgG class.

Unlike active vacc ination, passive vaccination provides immediate protection that lasts for about three months. The half-life of IgG antibodies is 21 days.

The gamma globulin preparations must be injected parenterally. In addition to the desired antibodies, they also contain antibodies directed against many other antigens. The amount of the desired antibody may be small.

The alternative is so-called hyperimmune sera, sera from selected donors with high titers against a specific pathogen. However, such sera cannot be produced in large quantities.

Human donors are homologous antibodies, animal donors are heterologous antibodies. The heterologous antibodies contain proteins foreign to the species and are therefore immunogenic themselves.

Furthermore, there are various immunoglobulin preparations with antibody mixtures that are used for people with severe immunodeficiency. They passively immunize against a variety of infections.

Passive immunization can also occur against snake and scorpion venoms, as well as against rhesus factor incompatibility between mother and child during pregnancy.

Passive immunization occurs physiologically when maternal IgG antibodies pass to the fetus via the placenta or IgA antibodies are transferred with breast milk (so-called nest protection).

Tetanus, diphtheria, hepatitis A; hepatitis B, varicella-zoster virus, cytomegalovirus, rabies, measles, botulism. Administration of convalescent serum for COVID-19.

There is a risk of triggering serum sickness with fever, circulatory reactions, arthritis, conjunctivitis and exanthema.

In tumor therapy as well as in immunosuppression, recombinant monoclonal antibodies, which are produced biotechnologically, are increasingly used.

1. Hof H (2019). Vaccinations. In: Hof H, Schlüter D, Dörries R, eds Duale Reihe Medizinische Mikrobiologie. 7th, completely revised and expanded edition. Stuttgart: Thieme p 738

Antibodies or antisera for passive immunization are available against these diseases:

• Botulism (meat poisoning caused by botulinum bacteria)
• Cytomegalovirus infection (CMV infection)
• Intestinal colic caused by Clostridium difficile (recurrence)
• Diphtheria
• Hepatitis A
• Hepatitis B
• Measles
• RSV infection (genetically engineered)
• Rubella
• Tetanus = lockjaw
• Rabies
• COVID-19 infections