Abstract

Marine mammal immunology is a relatively new but rapidly growing discipline. Recent applications include attempts at better understanding important fields such as the importance of the immune system in disease, the development of marine mammal vaccines, and the potential adverse health effects of pollutants or stress. Nevertheless, ethical, logistical and economical constraints greatly limit the number and extent of experimental studies. There is a need for a surrogate animal model that will adequately represent the marine mammal immune system to support research in marine mammal fundamental and applied immunology.

Mice homozygous for the severe combined immunodeficiency (SCID) mutation lack functional B and T lymphocytes, and are thus unable to generate a specific immune response. They therefore lack the ability to reject a graft. Taking advantage of this situation, we engrafted SCID mice with cells of cetacean immune system (collected from blood of live animals or immune organs of recently dead animals), and demonstrated the ability of those cells to, beyond not getting rejected, populated the mouse spleen and circulated in blood. In an attempt to verify the functionality of those cetacean cells, we vaccinated mice with canine distemper virus (CDV). The generation of antigen-specific T lymphocytes was demonstrated in several, although not all, mice. We nevertheless failed to demonstrate CDV-specific antibodies in plasma samples from the same mice.

Cetacean-reconstituted SCID mice represent an attractive and practical in vivo model to study the functionality of the marine mammal immune system. We intend to pursue the development of this model for vaccine-related, as well as disease pathophysiology and immunotoxicological applications.

Acknowledgement

We would like to thank the staff at Mystic Aquarium and Sea World for providing samples. This study was partially funded by a grant from the Morris Animal Foundation, and the Oiled Wildlife Research Program.