Identification of the Critical Amino Acid Residues of Immunoglobulin E and Immunoglobulin G Epitopes in α-Lactalbumin by Alanine Scanning Analysis.
α-Lactalbumin represents one of the major allergens causing cow milk allergy. Few studies have clearly evaluated immunological relationships between immunoglobulin E (IgE) and immunoglobulin G (IgG)-binding epitopes of α-lactalbumin. IgE- and IgG-binding epitopes were immunolabeled with individual sera from cow milk-allergic patients. Alanine scanning of immunodominant epitopes was used to identify the critical amino acid (aa). Our initial data revealed Val8, Phe9, Arg10, Tyr103, Leu105, and His107were the critical aa for IgE-binding epitope. The critical aa of IgG-binding epitopes were Phe9, Leu15, Pro24, Trp26, and His32. This study will provide necessary information to alter the cDNA to encode a protein capable of activating milk-specific T cells, but with reduced IgE- or IgG-binding capacity.
Beijing Key Laboratory of Food Flavor Chemistry & Beijing Higher Inst. Engineering Research Center of Food Additives and Ingredients, Beijing Technology and Business Univ, Haidian District, Beijing, 100048, P. R. China. congyj@th.btbu.edu.cn.
Cong
C
Yanjun
Beijing Key Laboratory of Food Flavor Chemistry & Beijing Higher Inst. Engineering Research Center of Food Additives and Ingredients, Beijing Technology and Business Univ, Haidian District, Beijing, 100048, P. R. China.
Zhou
Z
Shengyun
Dept. of Dermatology, Beijing Friendship Hospital, Capital Medical Univ, Xichen District, Beijing, 100050, P. R. China.
Li
L
Linfeng
D000409:Alanine / Q000737:chemistry*; D000485:Allergens / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000737:chemistry; D002417:Cattle; D002675:Child, Preschool; D018076:DNA, Complementary / Q000378:metabolism; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D007223:Infant; D007768:Lactalbumin / Q000737:chemistry*; D008892:Milk / Q000276:immunology; D016269:Milk Hypersensitivity / Q000276:immunology*; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D015398:Signal Transduction
D000485:Allergens; D002364:Caseins; D018076:DNA, Complementary; D000939:Epitopes; D007074:Immunoglobulin G; D010455:Peptides; D007073:Immunoglobulin E; D007768:Lactalbumin; D000409:Alanine
cow milk allergy; critical amino acid; epitope; α-lactalbumin