A 77-kilodalton protein of Cryptococcus neoformans, a member of the heat shock protein 70 family, is a major antigen detected in the sera of mice with pulmonary cryptococcosis.
Heat shock proteins (HSPs) from several pathogenic microbes have been shown to be target molecules of humoral responses as well as cellular immune responses. However, little is known about target molecules in pulmonary cryptococcosis. Western blotting analysis revealed that experimentally induced pulmonary cryptococcosis in (BALB/c x DBA/2)F1 mice was associated with the appearance of serum antibodies to a 77-kDa protein derived from Cryptococcus neoformans as well as to 18-, 22-, 25-, 36-, and 94-kDa proteins. Since the 77-kDa band also reacted with rabbit polyclonal antibodies against 70-kDa HSP (HSP70) family members, the protein was predicted to be a member of the HSP70 family. We also purified HSP70 directly from a C. neoformans cell extract by Mono Q fast protein liquid chromatography and ATP-agarose affinity column chromatography and showed that it was positive in immunoblot analysis using either serum from C. neoformans-infected mice or rabbit anti-HSP70 antibodies. N-terminal amino acid sequencing of this purified protein confirmed that the 77-kDa protein was a member of the HSP70 protein family. A 66-kDa protein, which coincidentally purified with the HSP70 protein and was identified as a member of the HSP60 family by N-terminal amino acid sequencing, was not reactive with sera from C. neoformans-infected mice. Thus, a protein associated with the HSP70 family and derived from C. neoformans was a major target molecule of the humoral response in murine pulmonary cryptococcosis.
Kakeya
H
H
Second Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Udono
H
H
Ikuno
N
N
Yamamoto
Y
Y
Mitsutake
K
K
Miyazaki
T
T
Tomono
K
K
Koga
H
H
Tashiro
T
T
Nakayama
E
E
Kohno
S
S
D000595:Amino Acid Sequence; D000818:Animals; D000908:Antibodies, Fungal / Q000097:blood / Q000276:immunology*; D015153:Blotting, Western; D018834:Chaperonin 60 / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003453:Cryptococcosis / Q000097:blood / Q000276:immunology* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005656:Fungal Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
D000908:Antibodies, Fungal; D018834:Chaperonin 60; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins