A vacuolar serine protease (Rho m 2) is a major allergen of Rhodotorula mucilaginosa and belongs to a class of highly conserved pan-fungal allergens.
BACKGROUND
Rhodotorula mucilaginosa is one of the most frequently encountered species of yeasts in our environment. We reported here a major allergen of R. mucilaginosa.


METHODS
A major R. mucilaginosa allergen (Rho m 2) was characterized by two-dimensional (2D) immunoblotting, protein sequencing, cDNA cloning and IgE cross-reactivity with fungal serine proteases.


RESULTS
Fourty-four sera (28%) from 157 bronchial asthmatic patients showed IgE-immunoblot reactivity against R. mucilaginosa extract. Among these 44 sera, 25 (57%) demonstrated IgE binding against a 31-kDa protein of R. mucilaginosa. Protein sequencing results suggest that it is a vacuolar serine protease. The corresponding cDNA clone encoding a mature protein of 312 residues was isolated. It shares 67-68% sequence identity with vacuolar serine protease allergens from three different Penicillium species (Pen ch 18, Pen o 18 and Pen c 18) and designated as Rho m 2 by the Allergen Nomenclature Committee. The native and recombinant Rho m 2 react with IgE antibodies and monoclonal antibody (MoAb) FUM20 against fungal serine proteases. IgE cross-reactivity between nRho m 2 and nPen ch 18 was observed. It was also detectable between rRho m 2 and rPen o 18.


CONCLUSIONS
Our results suggest that R. mucilaginosa may also be a significant causative agent of human respiratory allergic disorders. We identified a vacuolar serine protease as a major allergen of R. mucilaginosa (Rho m 2) and a pan allergen of prevalent airborne fungal species. We detected IgE cross-reactivity among these highly conserved serine protease pan-fungal allergens.
Chou
Hong
H
Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
Tam
Ming F
MF
Lee
Shinn-Shing
SS
Tai
Hsiao-Yun
HY
Chang
Ching-Yun
CY
Chou
Chang-Ter
CT
Shen
Horng-Der
HD
D000485:Allergens / Q000145:classification / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000946:Antigens, Fungal / Q000145:classification / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D017124:Conserved Sequence; D003429:Cross Reactions / Q000276:immunology; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D012248:Rhodotorula / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D012697:Serine Endopeptidases / Q000235:genetics / Q000276:immunology*; D014617:Vacuoles / Q000201:enzymology
D000485:Allergens; D000946:Antigens, Fungal; D018076:DNA, Complementary; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D012697:Serine Endopeptidases