Antisera

Antisera are preparations of serum that contain antibodies directed against specific antigens. They are used to confer passive immunity and as reagents in diagnostic immunology and immunotherapy. Traditionally, antisera are derived from the blood of immunized animals such as horses, rabbits, or goats. After immunization with a target antigen, the animal’s serum is collected and processed to concentrate or purify the immunoglobulins. The term antisera generally refers to polyclonal antibody mixtures; monoclonal antibodies, produced from a single B-cell clone, are related therapeutic agents but are not considered antisera.

Production and types

Antisera are produced by immunizing a donor with a particular antigen and harvesting the resulting serum. The antibodies present are polyclonal, recognizing multiple epitopes on the antigen. In some contexts, human antisera may be prepared from donors who have encountered a pathogen or toxin. Monoclonal antibodies, while functionally similar in recognizing a specific antigen, are produced via hybridoma technology and are not antisera, as they are single-clone products rather than complex serum mixtures.

Uses

Therapeutically, antisera include antivenoms and antitoxins that neutralize toxins or venom, providing rapid, short-term protection. In diagnostics, antisera serve as reagents in immunoassays, agglutination tests, precipitation reactions, and immunofluorescence to detect or identify pathogens or antigens.

Safety and regulation

Risks include hypersensitivity reactions, serum sickness, and, with animal-derived products, potential pathogen transmission if not properly screened. Batch-to-batch variability can affect potency and specificity. Modern practice increasingly favors purified immunoglobulins or monoclonal/human recombinant antibodies for improved safety and consistency, with antisera and related biologics subject to stringent regulatory oversight and quality control.