Han S H, Chang Z N, Chi C W, Perng H J, Liu C C, Tsai J J, Tam M F
Institute of Microbiology and Immunology, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China.
J Allergy Clin Immunol. 1993 Oct;92(4):549-58. doi: 10.1016/0091-6749(93)90079-u.
Cyn d I has been found to be the major allergen of Bermuda grass (Cynodon dactylon) pollen, but its exact nature remains to be clarified.
Cyn d I, the major allergen of Bermuda grass (Cynodon dactylon) pollen, was purified by monoclonal antibody (MoAb) affinity chromatography, and its biochemical and immunologic properties were characterized. Anti-Cyn d I MoAb 4-37, which recognizes all of the isoallergens of Cyn d I, was chosen as the immunosorbent.
The purified protein has an amino acid composition similar to that of the group I allergens of other grass pollens. It appears as a single 34 kd band or as a mixture of 34 and 29 kd polypeptides in sodium dodecylsulfate-polyacrylamide gel electrophoresis analysis. The hydrophobicity of these two polypeptides is similar because they have the same retention time on a C18 reverse-phase column when a trifluoroacetic acid/H2O/CH3CN buffer system is used. The N-terminal amino acid sequence of the 34 kd component has a 60% homology with residues of 1-25 of Lol p I, whereas that of the 29 kd component has a 68% homology with residues 31-68 of Lol p I. In addition, this 29 kd polypeptide can be recognized by another anti-Cyn d I MoAb 1-61.
These results suggest that the 29 kd component is derived from Cyn d I. In spite of the similarity in the amino acid composition between Cyn d I and group I allergens of other grass pollens, none of our four anti-Cyn d I MoAbs cross-reacted with 10 other grass pollens tested, including ryegrass pollen. Despite biochemical similarity with other group I allergens, the B-cell epitopes on Cyn d I are different from those on other grass pollens.
