Immunological Impact of Metals in Harbor Seals (Phoca vitulina) of the North Sea

Abstract

Environmental pollutants may affect the immune system of marine mammals in many areas of the industrialized world. This study provides the first evidence for metal-induced hypersensitivity in harbor seals and demonstrates a relationship between this immunopathy and the level of metals in blood. The concentrations of 20 essential and nonessential elements were analyzed in the blood of 13 harbor seals from the North Sea. In addition, their T-lymphocyte response to metals in terms of hypersensitivity was investigated using a lymphocyte transformation test (LTT) according to the MELISA (memory lymphocyte immuno-stimulation assay) modification. The results showed metal hypersensitivities in 7 of 11 seals investigated in MELISA (data from two seals could not be assessed), reflecting a positive or possible positive reaction in 13 of 154 total single tests. Four animals responded to one metal and three animals to multiple metals. The sensitizing metals were molybdenum (Mo), titanium (Ti), nickel (Ni), chromium (Cr), aluminum (Al), lead (Pb), and tin (Sn). Furthermore, the seals with a Ni-, Al-,.and Cr-sensibilization showed the highest concentrations of these metals in blood. In 8 of the 13 positive cases, elevated blood metal concentrations correlated with the hypersensitivity reaction. Summarizing, we demonstrate in this first pilot study the potential immunological impact of metals in seals, a topic rarely investigated previously. Our results show the value of a combined biological and effect-monitoring tool to investigate pollution-induced immunopathies in live animals.

Postmortem Health and Pollution Investigations on Harbor Seals (Phoca vitulina) of the Islands Helgoland and Sylt

“…The non-and PWM-stimulated lymphocyte proliferations were within the range measured for seals in the Wadden Sea (Table S2) [25]. All metalspecific SI values were in the normal range >0.1 and <3 (Table S2).…”

“…The special modification, MELISA (Memory Lymphocyte Immunostimulation Assay), was performed as previously described in the Laboratory Center Bremen, Germany [25][26][27]. The mitogen-and nonstimulated lymphocyte proliferation was tested as well as the metalspecific proliferation after stimulation with the following metals/metal species: Al, Au, Be, Cd, Cr, Cu, ethylmercury (EtHg), mercurychloride (HgCl), methylmercury (MeHg), phenylmercury (PhHg), Mo, Ni, Pb, Sn, and Ti.…”

Essential and Toxic Elements in Blood Samples of Harbor Seals (Phoca vitulina) from the Islands Helgoland (North Sea) and Anholt (Baltic Sea): A Comparison Study with Urbanized Areas

“…Interestingly, Ni concentrations in the sediment of the northeastern Wadden Sea regions of Dithmarschen, North-Frisia, or Sylt-Rømø were higher and showed an increasing trend over the past years compared with southwest regions of the Wadden Sea (Bakker et al 2009). Seals from Rømø showed besides elevated Ni blood levels, Ni-specific hypersensitivity reactions, potentially as a result of a chronic metal influence (Kakuschke et al 2005). Similar immunological reactions were found for the metals Al, Cr, Mo, Pb, Sn, and Ti.…”

“…Blood sampling of harbor seals is considered minimally invasive and allows the analyses of pollutants, biomarkers, and health parameters additionally to in vitro cell experiments from living animals. For the North Sea, several investigations have been performed to measure contaminants (Griesel et al 2006;Das et al 2008;Griesel et al 2008;Kakuschke et al 2009;Weijs et al 2009a, b, c;Kakuschke et al 2010b), assess immune cell functions (De Swart 1995;Ross 1995;Kakuschke et al 2005;Das et al 2008;Dupont et al 2013), or analyse biomarkers Hasselmeier et al 2008;Kakuschke et al 2010a;Grebe et al 2010Grebe et al , 2011Grebe et al , 2012Kakuschke et al 2013) in blood samples of harbor seals. Most of these studies focused on animals closed to urbanized areas along the Wadden Sea coast.…”

Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

“…Accessible samples from free-ranging marine mammals are generally limited to blood, fur/hair, skin biopsies, saliva, and feces (Andrade et al, 2007;Fossi and Marsili, 1997;Griesel et al, 2008;Stavros et al, 2008a). Blood from free-ranging marine mammals has become increasingly used in determining baseline levels of trace elements (Brookens et al, 2007;Bryan et al, 2007;Das et al, 2008;Gray et al, 2008;Griesel et al, 2008;Kakuschke et al, 2005;Nielsen et al, 2000;Stavros et al, 2008a;Woshner et al, 2008). Their concentrations found in blood may be useful in comparing contaminant exposure to humans and other mammals.…”