During human
infection, Aspergillus fumigatus secretes a 18-kDa
protein that can be detected as an immunodominant
antigen in the urine of infected patients. Recently, this
protein was shown to be
mitogillin, a ribotoxin that cleaves a single phosphodiester bond of the 29S rRNA of eukaryotic ribosomes. We proved the immunogenic capacity of
mitogillin in a rabbit animal model, indicating its usefulness as an
antigen for serological diagnosis of invasive
aspergillosis. The
mitogillin gene from A. fumigatus was transferred from plasmid pMIT+ to expression vector pQE30 and expressed in Escherichia coli as a fusion
protein. Purified recombinant
mitogillin was recognized by serum
immunoglobulin G (
IgG) of polyclonal rabbit sera that were obtained by immunization with purified native
mitogillin. Consequently, we developed an
enzyme-linked
immunosorbent assay for detection of
IgG,
IgM, and
IgA antibodies to recombinant
mitogillin. In serum samples of patients suffering from aspergilloma (AO; n = 32),
invasive pulmonary aspergillosis (IPA; n = 42), or invasive disseminated
aspergillosis (IDA; n = 40), a good correlation of production of
IgG antibody against
mitogillin and clinical disease was observed (for patients with AO, 100% [32 of 32] were positive; for patients with IPA, 64% [31 of 42] were positive; for patients with IDA, 60% [24 of 40] were positive). In contrast, positive titers for serum
IgG and
IgM antibodies against
mitogillin were found in only 1.3% of the serum samples of healthy volunteers and positive titers for
IgA antibody were found in only 1.0% of the serum samples of healthy volunteers (n = 307; specificity = 95.4%). These results indicate that recombinant
mitogillin expressed in E. coli can be used for improvement of the serodiagnosis of A. fumigatus-associated diseases.