Hi Suipwksiow,

Yes, it's possible that inducing anti-antibody drug Ab by animal model with robust immunity (e.g. BALB/c mice). Thus, there were several studies used immunodeficient animal model such as SCID, nude or NSG mice for investigating the therapeutic efficacy of antibody drug to xenografted malignancies. In addition, it is also possible that inducing anti-idiotypic Ab even you treated antibody drugs to animal with the same species (e.g. treated mouse tumor with mouse anti-tumor antibody).

Hope this help.

Yes, foreign antibodies can and will introduce immunity in an immunocompetent organism - That became apparent with the first clinical trials of monoclonal antibody-based therapeutics (see HAMA response https://www.google.ch/search?client=safari&rls=en&q=HAMA+antibody&ie=UTF-8&oe=UTF-8&gfe_rd=cr&dcr=0&ei=OZXkWYqQKqTC8ge4-7-wBw). By antibody humanisation, researchers are trying to minimize the antigenic potential, but even antibodies derived from a human library can elicit an immune response. Besides keeping the sequence of a therapeutic antibody as close to the human antibody sequences, alternative approaches try to get rid of potential T-cell epitopes in the variable sequences (de-immunization, https://www.google.ch/search?client=safari&rls=en&q=antibody+de-immunization&ie=UTF-8&oe=UTF-8&gfe_rd=cr&dcr=0&ei=VZfkWb_3JKHC8gfV86TgAQ). Induction of tolerance by targeting Treg epitopes is discussed as a further step in reducing the immune responses against protein-based therapeutics (e.g. Article Beyond humanization and de-immunization: Tolerization as a m...

If foreign species (different species of antibody to animal injected) there is a good chance that you will en up with antibodies. Second and third time treatments usually result in type 3 hypersensitivity reaction (immune reaction against foreign antibody). If species of host and origin of antibody is identical, likelihood of adverse effects are minimized. However, this occasionally happens.