Immunoblotting of human cancer cell lines pretyped by RT-PCR for CT10/MAGE-C2 mRNA expression with mAb LX-CT10.5 (NP-40 detergent lysates, chemiluminescence detection). Positive reaction of mAb LX-CT10.5 with a protein of an apparent molecular weight of 49 kDa (lane 1) in lysates of CT10/MAGE-C2 mRNA-positive melanoma cell lines SK-MEL-37 (lane 2) and SK-MEL-55 (lane 3); no reactivity was seen with the CT10/MAGE-C2 mRNA-negative melanoma cell line SK-MEL-24 (lane 4); the proteins detected by mAb LX-CT10.5 co-migrate with the 49 kDa E. coli-derived recombinant CT10/MAGE-C2 protein (arrow, lane 5).