Anti-human immunoglobulin G antibody production in rabbits: Comparison of intramuscular and subcutaneous methods

Anti-human immunoglobulin G (IgG) antibody is produced against human IgG in various laboratory animals. The present study tried not only to produce anti-human IgG, but also to assess different antigen injection techniques leading to optimal production of anti-human globulin. The antibody was separated from human serum using precipitation method with sodium sulfate. It was then purified through diethylaminoethyl Sepharose CL-6B ion exchange chromatography. The purified IgG was mixed with Freund’s complete adjuvant and injected to two trios of rabbits either intramuscularly or subcutaneously. After the first injection, the animals received weekly injections of antigen with Freund’s incomplete adjuvant. The dose of antigen in each injection was 1.2 ml of purified IgG with a concentration of 115 µg/ml. Venous blood samples were taken from all rabbits and the produced anti-human globulin was evaluated by single radial immunodiffusion (SRID). According to the results of SRID, the diameter of the halo created by the antigen-antibody complex was significantly higher in the plate containing anti-human IgG produced after the intramuscular injections than after subcutaneous injections. The concentrations of anti IgG antibody were 83.40 and 72.28 µg/ml in intramuscular and subcutaneous methods, respectively. Our findings suggested that compared to subcutaneous injections, intramuscular injections of human IgG are significantly more effective in inducing the production of anti-human IgG antibody.