Tella José L, Lemus Jesús A, Carrete Martina, Blanco Guillermo
Department of Conservation Biology, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, Sevilla, Spain.
PLoS One. 2008 Sep 29;3(9):e3295. doi: 10.1371/journal.pone.0003295.
cological immunology requires techniques to reliably measure immunocompetence in wild vertebrates. The PHA-skin test, involving subcutaneous injection of a mitogen (phytohemagglutinin, PHA) and measurement of subsequent swelling as a surrogate of T-cell mediated immunocompetence, has been the test of choice due to its practicality and ease of use in the field. However, mechanisms involved in local immunological and inflammatory processes provoked by PHA are poorly known, and its use and interpretation as an acquired immune response is currently debated.
Here, we present experimental work using a variety of parrot species, to ascertain whether PHA exposure produces larger secondary than primary responses as expected if the test reflects acquired immunocompetence. Moreover, we simultaneously quantified T-lymphocyte subsets (CD4(+), CD5(+) and CD8(+)) and plasma proteins circulating in the bloodstream, potentially involved in the immunological and inflammatory processes, through flow cytometry and electrophoresis.
Our results showed stronger responses after a second PHA injection, independent of species, time elapsed and changes in body mass of birds between first and second injections, thus supporting the adaptive nature of this immune response. Furthermore, the concomitant changes in the plasma concentrations of T-lymphocyte subsets and globulins indicate a causal link between the activation of the T-cell mediated immune system and local tissue swelling.
CONCLUSIONS/SIGNIFICANCE: These findings justify the widespread use of the PHA-skin test as a reliable evaluator of acquired T-cell mediated immunocompetence in diverse biological disciplines. Further experimental research should be aimed at evaluating the relative role of innate immunocompetence in wild conditions, where the access to dietary proteins varies more than in captivity, and to ascertain how PHA responses relate to particular host-parasite interactions.
生态免疫学需要可靠地测量野生脊椎动物免疫能力的技术。PHA皮肤试验，即皮下注射一种有丝分裂原（植物血凝素，PHA）并测量随后的肿胀情况作为T细胞介导免疫能力的替代指标，因其实用性和在野外易于操作而成为首选测试方法。然而，PHA引发的局部免疫和炎症过程所涉及的机制尚不清楚，并且其作为获得性免疫反应的使用和解释目前存在争议。
在此，我们展示了使用多种鹦鹉物种进行的实验工作，以确定如果该测试反映获得性免疫能力，PHA暴露是否会如预期那样产生比初次反应更大的二次反应。此外，我们通过流式细胞术和电泳同时量化了血液中循环的T淋巴细胞亚群（CD4(+)、CD5(+)和CD8(+)）以及血浆蛋白，这些可能参与免疫和炎症过程。
我们的结果表明，第二次注射PHA后反应更强，与物种、时间间隔以及第一次和第二次注射之间鸟类体重的变化无关，从而支持了这种免疫反应的适应性本质。此外，T淋巴细胞亚群和球蛋白血浆浓度的伴随变化表明T细胞介导的免疫系统激活与局部组织肿胀之间存在因果联系。
结论/意义：这些发现证明了PHA皮肤试验作为不同生物学学科中获得性T细胞介导免疫能力的可靠评估方法被广泛使用是合理的。进一步的实验研究应旨在评估先天免疫能力在野生条件下的相对作用，在野生条件下，获取膳食蛋白质的情况比圈养时变化更大，并确定PHA反应与特定宿主 - 寄生虫相互作用之间的关系。
Zotero 插件
