Use of sera from humans and dolphins with lacaziosis and sera from experimentally infected mice for Western Blot analyses of Lacazia loboi antigens

Abstract

Antibodies in the sera of patients with lacaziosis recognized an approximately 193-kDa antigen and other Lacazia loboi antigens. Paracoccidioides brasiliensis gp43 antigen was detected by all evaluated sera, but they failed to detect a protein with the same molecular mass in L. loboi extracts. This study is the first to examine the humoral response to L. loboi antigens by using multiple host sera.

FIG. 1.

Human parakeloidal (A) and dolphin verrucous (B) lesions from two of the hosts with lacaziosis used in this study. The histopathology of these lesions is shown in panels C (human) (silver stain; magnification, ×100) and D (dolphin) (silver stain; magnification, ×40).

FIG. 2.

Coomassie blue-stained sodium dodecyl sulfate-polyacrylamide gel showing purified Paracoccidioides brasiliensis gp43 (lane 1) and the profile of an Lacazia loboi protein extract (lane 2). The figure shows the ∼193-kDa immunodominant antigen (arrow) as well as other proteins in the L. loboi protein extract. The asterisks indicate common proteins detected by the sera tested in this study. Lane M, molecular mass marker.

FIG. 3.

Western blot analyses of transferred proteins on nylon membranes. The antibodies in the serum from a human with lacaziosis weakly detected Paracoccidioides brasiliensis gp43 (lane 1a). This serum strongly detected an ∼193-kDa immunodominant antigen (arrow) as well as six other weak bands (asterisks) (lane 1b). The IgG in the serum from the experimentally infected mouse weakly detected P. brasiliensis gp43 (lane 2a). The mouse antibodies strongly detected the ∼193-kDa immunodominant antigen (arrow) as well as seven other proteins (asterisks) and an ∼48-kDa protein not detected by the other sera (lane 2b, arrowhead). The antibodies in the dolphin with lacaziosis slightly detected P. brasiliensis gp43 (lane 3a). The antibodies strongly recognized the ∼193-kDa immunodominant antigen (arrow) and only one of the minor antigens previously detected in the L. loboi extract (lane 3b). The antibodies in the serum from the patient with paracoccidioidomycosis strongly detected gp43 (lane 4a). The antibodies of this patient also detected the immunodominant ∼193-kDa antigen (arrow) in the L. loboi extract as well as other antigens (asterisks), including a 43-kDa antigen (arrowhead) (lane 4b). The molecular mass marker (lanes M) appears in each of the panels.