Supplementary Material for: Characterization of T Cell Epitopes in Bovine α-Lactalbumin

Background: Recent studies have indicated that peptides containing T cell epitopes may be used for immunotherapy. While for several cow's milk allergens the T cell epitopes have been described, the T cell epitopes in the major allergen α-lactalbumin (α-LAC) are unknown. Therefore, the aim of this study was to determine the T cell epitopes in α-LAC. Methods: Nineteen synthetic peptides spanning α-LAC were obtained. Cow's milk-specific T cell lines (TCLs) of 46 subjects were generated and tested for their specificity for α-LAC. The lines responding to α-LAC were subsequently tested to determine their activation in response to the peptides. Results: More than half of the TCLs generated did not respond to α-LAC or lost their responsiveness during subsequent experiments, which indicates that α-LAC has low immunogenicity. Only 8 TCLs recognized 1 or more peptides. The recognition of the peptides was diverse and no major epitopes could be defined. Conclusion: The immunogenicity of α-LAC is very low compared to other major allergens in cow's milk. Moreover, there seems to be no dominant epitope present in the protein. Therefore, it seems unlikely that peptides of this protein can be used for immunotherapy.

研究背景：近期研究表明，携带T细胞表位（T cell epitopes）的肽类物质可用于免疫治疗。尽管目前已对多种牛奶过敏原的T细胞表位进行了阐释，但主要过敏原α-乳白蛋白（α-lactalbumin, α-LAC）中的T细胞表位仍未明确。因此，本研究旨在确定α-LAC中的T细胞表位。研究方法：获取了19条覆盖α-LAC全序列的合成肽。对46名受试者的牛奶特异性T细胞系（T cell lines, TCLs）进行构建，并检测其对α-LAC的特异性。随后，对可响应α-LAC的细胞系开展检测，以明确其在对应肽类刺激下的活化情况。研究结果：构建的TCLs中超过半数未对α-LAC产生响应，或在后续实验中丧失了响应能力，这表明α-LAC的免疫原性较低。仅8条TCLs可识别1条或多条肽类。对肽类的识别呈现多样性，无法确定主要表位。研究结论：相较于牛奶中的其他主要过敏原，α-LAC的免疫原性极低。此外，该蛋白质中似乎不存在显性表位。因此，利用该蛋白的肽段开展免疫治疗的可能性较低。