Passive Antibody Therapy

 

Passive Immunization

The effect of injecting immunoglobulin was first discovered in the late 1800s. Since then, Passive immunization has become standard practice in many cases.

Preparation of Immunoglobulin

Passive immunizations are prepared from the pooled plasma of thousands of donors, representing a sample of anitbodies that respond to a broad variety of pathogens. A gram of intravenous immunoglobulin (IVIG) may contain 1018 molecules of IG - mostly IgG and may represent up to 107 different antibody specificities.

Patients often receive 200-400 mg per kg, meaning a 70 kg man would receive 14-28 g every 3-4 weeks.

IVIG is treated exhaustively with solvents and detergents to reduce the risk of infectivity and to reduce aggregates that might trigger massive activation of the complement pathway and subsequent anaphylaxis.

Effects of IVIG

One of the most important uses of administered antibody is the recruitment of the complement pathway to destroy pathogens. Opsonization will target pathogens for phagocytosis, and toxins will be neutralized. Antibody-dependent cell-mediated cytotoxicity (ADCC) by NK cells also occurs.

Uses of IVIG

IgG is given to immunocompromized patients both IM and IV.

IgG given to healthy people

RSV IgG given to premature babies

given if risk of tetanus without recent booster

rabies if bitten

anti-venom