Fig. 2.

Proteomic analysis of Mage-A4 expression in normal human testicular tissue. A, Silver stained IEF 2D PAGE analysis with MS identification of the Mage-A4 protein (B) 2D Western blot analyses of Mage-A4 expression patterns in normal human testicular tissue lysates using three antibodies (mAb 57B, mAb CPTC-MageA4–1, and rab Ab 1982). Several polypeptides were detected by the three antibodies; the major peptide form corresponding to the MS-identified protein spot is indicated with white arrows and the other potential post-translationally modified forms are indicated with black arrowheads. One additional, lower Mw, polypeptide was observed with rab Ab 1982 and is indicated with a gray arrow (C). Immunohistochemical expression analysis of Mage-A4 in FFPE testicular biopsy specimens with normal spermatogenesis using rab Ab 1982 (left hand panel). Immunoreactivity occurred primarily in spermatogonia, presenting a characteristic “pearl-necklace ” appearance. Pre-incubation control assay with purified recombinant Mage-A4 protein (recMage-A4) blocked immunoreactvity in a tandem section (right hand panel). Scale bar, 100 μm.