Breeding and Maintenance of Immunodeficient Mouse Lines under SPF Conditions—A Call for Individualized Severity Analyses and Approval Procedures
Institute of Immunology, Charité Universitätsmedizin, Campus Berlin Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany
Max Delbrück Centrum Berlin, Campus Berlin Buch, Robert-Rössle-Str. 10, 13125 Berlin, Germany
Faculty of Humanities and Cultural Studies—Catholic Theology, Bergische Universität Wuppertal, Gaußstraße 20, 42119 Wuppertal, Germany
Nuvisan Innovation Campus Berlin GmbH, Muellerstrasse 178, 13353 Berlin, Germany
Animal Behavior and Laboratory Animal Science, Institute for Animal Welfare, Freie Universität Berlin, Königsweg 67, 14163 Berlin, Germany
Author to whom correspondence should be addressed.
These Authors contributed equally to this work.
Academic Editor: Vera Baumans
Received: 27 April 2021 / Revised: 4 June 2021 / Accepted: 10 June 2021 / Published: 15 June 2021
In the EU, the breeding of genetically modified laboratory animals is defined as an animal experiment, if the animals may experience pain, suffering or harm due to the genetic modification. In most cases, modifications of the immune system do not lead to pain, suffering, or harm given the animals are kept under specific pathogen-free housing conditions. Nevertheless, the EU working group on genetically altered animals defined SPF housing conditions as “Refinement”. According to this working group, applied refinement strategies for breeding genetically modified animals do not exclude them from project licensing. Thus, theoretical suffering, pain or harm is assumed without applying methods of actual burden assessment. Furthermore, the definition of SPF as a refinement strategy rather than a standard husbandry procedure leads to incomprehension among the scientific community in the EU. Here, we discuss the ethical basis of animal experiments as well as the current legal situation for immunodeficient animals. Furthermore, we discuss potential pain, suffering, or harm of immunodeficient animals from an immunological perspective. Finally, we briefly outline an animal welfare-oriented approach to severity assessment of immunodeficient mice.