FAQ
Q: Which species should I use for polyclonal antibody production?
A: Several factors are considered when determining the best species for polyclonal antibody production. If a protein antigen is homologous to a protein found in the species being immunized, a different species should be considered. For example, chickens frequently generate antibodies to conserved mammalian proteins. The amount of antibody required also determines the appropriate host species. Small amounts of sera containing antibody are obtained from mice, rats and guinea pigs. Larger amounts of sera are obtained from rabbits, the most popular species at SDI for immunization. The largest volumes of sera (or plasma) are obtained from sheep and goats. Also, consider the time required to obtain a fully-matured antibody response. Rabbits, chickens, guinea pigs, rats, and mice typically require 4 immunizations over approximately 70 days to reach optimal immune response. Goats and sheep require more immunizations over 200 days to reach full immune maturity.
Q: What type of antigens can be used for polyclonal antibody production?
A: Nearly any molecule can be injected into animals, but some molecules are much better immunogens than others. Full-length proteins, either expressed recombinantly or purified from natural sources, are the best immunogens. Peptides may be easier and cheaper to produce, but anti-peptide antibodies frequently fail to recognize the full-length protein from which they were derived. Small molecules such as vitamins, antibiotics, drugs, dyes, and metabolites are not immunogenic due to their small size. This class of antigen is known as haptens. Haptens must be conjugated to carrier proteins before they can be recognized by the immune system. Other molecules such as carbohydrates, lipoproteins, and phospholipids are poor immunogens, either generating undesirable IgM responses only or failing to generate any response.
Q: To make large volumes of antisera, should I start additional animals or should I use extended immunization protocols on fewer animals?
A: Consider your timeline and consider the amount of antibody you require in a single lot of antibody product. If large amounts of antibody are required in a short period of time, more animals are started on an immunization protocol. If a single large lot of antibody product is desired, more animals are started on an immunization protocol. A single large lot of antibody minimizes the amount of qualification testing required before use in your laboratory or manufacturing operation. If you are uncertain of the antibody response that will be elicited by your antigen, extended immunization protocols may be preferable. In this approach, several animals might be started on a standard immunization protocol. At the conclusion of the standard protocol, the animals with the best antibody response are continued on extended protocols.