The ability of marine mammals to cope with environmental challenges is a key determining factor in strandings and successful release of rehabilitated animals. Dive behavior is related to foraging and thus survival. While dive adaptations have been well studied, it is unknown how the immune system responds to diving and whether health status impacts immune function during diving. This study investigated the functional response of ex situ immune cells from stranded phocids to in vitro increased pressure, over the course of rehabilitation. Blood samples were drawn from stranded harbor seals (Phoca vitulina), gray seals (Halichoerus grypus) and harp seals (Phoca groenlandica) at the time of admit to the Mystic Aquarium, Mystic, CT and again after rehabilitation (pre-release). Phagocytosis, lymphocyte proliferation and immune cell activation were measured in vitro, with and without exposure to 2000 psi (simulated dive depth of 1360 m). Plasma epinephrine and norepinephrine, and serum cortisol were measured in vivo. All hormone values decreased between admit and release conditions. Under admit or release conditions, pressure exposures resulted in significant changes in granulocyte and monocyte phagocytosis, granulocyte expression of CD11b and lymphocyte expression of the IL2 receptor (IL2R). Overall, pressure exposures resulted in decreased phagocytosis for admit conditions, but increased phagocytosis in release samples. Expression of leukocyte activation markers, CD11b and IL2R, increased and the response did not differ between admit and release samples. Specific hematological and serum chemistry values also changed significantly between admit and release and were significantly correlated with pressure-induced changes in immune function. Results suggest (1) dive duration affects the response of immune cells, (2) different white blood cell types respond differently to pressure and (3) response varies with animal health. This is the first study describing the relationship between diving, immune function and health status in phocids.

中文翻译：

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健康状况对压力引起的嗜酸性免疫功能变化的影响及其对潜水能力的影响

海洋哺乳动物应对环境挑战的能力是搁浅和成功释放康复动物的关键决定因素。潜水行为与觅食和生存有关。虽然已经对潜水适应进行了深入研究，但尚不清楚免疫系统如何对潜水做出反应，以及健康状况是否会影响潜水期间的免疫功能。本研究调查了在康复过程中，异位免疫细胞对体外压力增加的功能反应。在进入 Mystic Aquarium, Mystic, CT 时和康复后（预释放）再次从搁浅的海豹 (Phoca vitulina)、灰海豹 (Halichoerus grypus) 和竖琴海豹 (Phoca groenlandica) 中抽取血液样本。吞噬作用，在体外测量淋巴细胞增殖和免疫细胞活化，无论是否暴露于 2000 psi（模拟潜水深度为 1360 m）。在体内测量血浆肾上腺素和去甲肾上腺素以及血清皮质醇。所有激素值在承认和释放条件之间下降。在允许或释放条件下，压力暴露导致粒细胞和单核细胞吞噬作用、CD11b 的粒细胞表达和 IL2 受体 (IL2R) 的淋巴细胞表达发生显着变化。总体而言，压力暴露导致承认条件下的吞噬作用降低，但释放样品中的吞噬作用增加。白细胞活化标志物 CD11b 和 IL2R 的表达增加，并且接纳和释放样品之间的反应没有差异。特定的血液学和血清化学值在入院和出院之间也发生了显着变化，并且与压力引起的免疫功能变化显着相关。结果表明（1）潜水持续时间影响免疫细胞的反应，（2）不同的白细胞类型对压力的反应不同，（3）反应因动物健康而异。这是第一项描述潜水、免疫功能和健康状况之间关系的研究。