Phenotypical characterization of changes in thymus and spleen associated with lymphoid depletion in free-ranging harbor porpoises (Phocoena phocoena)

Andreas Beineke, Ursula Siebert, Jeffrey L Stott, Gundi Müller, Wolfgang Baumgärtner

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Harbor porpoises from the North and Baltic Seas exhibit a higher incidence of bacterial infections compared to whales from less polluted arctic waters. Furthermore, thymic atrophy and splenic depletion, associated with elevated concentrations of environmental contaminants, such as polychlorinated biphenyls (PCB) and polybrominated diphenyl ether (PBDE) body burdens, have been found in wildlife harbor porpoises. Thus, there is currently a debate about the potential adverse effect of xenobiotics on the immune system and therefore on the health status of this and other marine mammal species. The aim of the present study was to characterize phenotypical changes in lymphoid organs of harbor porpoises and their possible association with increased disease susceptibility due to an impaired immune response in this marine mammal species. Therefore, 29 by-caught and stranded harbor porpoises were necropsied and the health status was evaluated based upon the severity of main pathological findings. In addition, the distribution of CD2-, CD3ε-, and CD45R-positive cells as well as B lymphocytes, MHC class II-expressing and antigen-presenting cells was determined in the thymus and spleen using immunohistochemistry. Thymic atrophy and splenic depletion were associated with an impaired health status in investigated whales. Phenotypical changes in atrophic thymuses were characterized by a depletion of immature cortical thymocytes and medullary B cells. Furthermore, findings in depleted spleens were consistent with a loss of peripheral T lymphocytes in the periarteriolar lymphoid sheath (PALS). Based upon the results, an altered thymopoiesis and impaired cellular immune function cannot be excluded in whales with evidence of lymphoid depletion.

Original languageEnglish (US)
Pages (from-to)254-265
Number of pages12
JournalVeterinary Immunology and Immunopathology
Issue number3-4
StatePublished - Jun 15 2007


  • Harbor porpoise
  • Immunohistochemistry
  • Leukocyte markers
  • Lymphoid depletion
  • Phenotypical characterization

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Immunology
  • veterinary(all)


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