Kelley K W, Greenfield R E, Evermann J F, Parish S M, Perryman L E
Am J Vet Res. 1982 May;43(5):775-9.
Three-week-old Holstein bull calves were used to investigate the effect of a 2-week chronic heat (35 C) or cold (-5 C) exposure on delayed-type hypersensitivity (DTH) reactions to purified protein derivative after sensitization with heat-killed Mycobacterium tuberculosis, contact sensitivity (CS) reactions to 1-fluoro-2,4-dinitrobenzene, and phytohemagglutinin (PHA) skin tests. Heat exposure reduced expression of DTH reactions by 42% and CS reactions by 38% at 24 hours after elicitation of the responses. The PHA-induced skin tests were not affected after 1 week of heat exposure, but this reaction was reduced by 20% after 2 weeks of heat exposure. The immune response of calves exposed to cold air temperatures was more complex. Cold exposure suppressed CS reactions by 39% at the end of both the 1st and 2nd weeks. The PHA response was reduced by 39% after 2 weeks of cold exposure. The DTH response depended on duration of cold exposure. The DTH reaction was increased by 42% after 1 week, but was reduced by 14% after 2 weeks. These data are consistent with the hypothesis that environmental stressors alter host resistance by affecting the immune system. Furthermore, these stress-induced changes in immune events depend on the type of immune response, the nature of the environmental stressor, and the length of time that calves are exposed to the stressor.
三周龄的荷斯坦公牛犊被用于研究为期两周的慢性热暴露（35摄氏度）或冷暴露（零下5摄氏度）对热灭活结核分枝杆菌致敏后对纯化蛋白衍生物的迟发型超敏反应（DTH）、对1-氟-2,4-二硝基苯的接触敏感性（CS）反应以及植物血凝素（PHA）皮肤试验的影响。在引发反应后24小时，热暴露使DTH反应的表达降低了42%，CS反应降低了38%。热暴露1周后，PHA诱导的皮肤试验未受影响，但热暴露2周后该反应降低了20%。暴露于冷空气温度下的犊牛的免疫反应更为复杂。在第1周和第2周结束时，冷暴露使CS反应分别抑制了39%。冷暴露2周后，PHA反应降低了39%。DTH反应取决于冷暴露的持续时间。冷暴露1周后，DTH反应增加了42%，但2周后降低了14%。这些数据与环境应激源通过影响免疫系统改变宿主抵抗力的假设一致。此外，这些应激诱导的免疫事件变化取决于免疫反应的类型、环境应激源的性质以及犊牛暴露于应激源的时间长度。
