Kohsaka Takuma, Hiragun Takaaki, Ishii Kaori, Hiragun Makiko, Kamegashira Akiko, Hide Michihiro
Department of Dermatology, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Department of Dermatology, Integrated Health Sciences, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Allergol Int. 2018 Jan;67(1):103-108. doi: 10.1016/j.alit.2017.05.009. Epub 2017 Jun 24.
Atopic dermatitis (AD) is exacerbated by sweating, and the skin of most patients with AD are resided by Malassezia (M.) fungi. Recently, MGL_1304 produced by Malassezia globosa was identified as the major histamine releasing antigen in human sweat.
The full length cDNA of the counterpart of MGL_1304 in Malassezia restricta (Mala r 8), was cloned by degenerate PCR and rapid identification of cDNA ends (RACE). Recombinant MGL_1304, and its counterparts, Mala s 8 (produced by Malassezia sympodialis) and Mala r 8 were prepared, and compared in their allergenicities by dot blot analysis and histamine release tests with sera and basophils of patients with AD.
The identities between MGL_1304 and Mala s 8, MGL_1304 and Mala r 8, and Mala s 8 and Mala r 8 were 68%, 78%, and 76%, respectively, in protein sequences. Dot blot analysis revealed that the level of IgE binding to Mala s 8 was higher than that of MGL_1304. However, histamine release tests revealed that MGL_1304 and Mala r 8 possessed higher activity than Mala s 8. In addition, the crude lysate of M. globosa showed higher histamine release ability than that of M. sympodialis.
Patients with AD showed hypersensitivities against MGL_1304 and its homologs. However, the allergenicities of the homologs are variable and the histamine release activities may be different from the solid-phase binding activities for IgE. Sweat allergy should be carefully evaluated with biological activities of MGL_1304 and its homologs of other Malassezia fungi residing on the skin.
特应性皮炎（AD）会因出汗而加重，大多数AD患者的皮肤都有马拉色菌（M.）真菌寄生。最近，球形马拉色菌产生的MGL_1304被确定为人类汗液中的主要组胺释放抗原。
通过简并PCR和cDNA末端快速鉴定（RACE）克隆了限制马拉色菌中MGL_1304对应物（Mala r 8）的全长cDNA。制备了重组MGL_1304及其对应物Mala s 8（由合轴马拉色菌产生）和Mala r 8，并通过斑点印迹分析以及对AD患者血清和嗜碱性粒细胞进行组胺释放试验来比较它们的致敏性。
MGL_1304与Mala s 8、MGL_1304与Mala r 8以及Mala s 8与Mala r 8的蛋白质序列同一性分别为68%、78%和76%。斑点印迹分析显示，IgE与Mala s 8的结合水平高于MGL_1304。然而，组胺释放试验显示，MGL_1304和Mala r 8的活性高于Mala s 8。此外，球形马拉色菌的粗裂解物显示出比合轴马拉色菌更高的组胺释放能力。
AD患者对MGL_1304及其同源物表现出超敏反应。然而，同源物的致敏性各不相同，组胺释放活性可能与IgE的固相结合活性不同。应结合MGL_1304及其皮肤上其他马拉色菌同源物的生物学活性，仔细评估汗液过敏情况。
