DETECTION OF TUMOR-SPECIFIC ANTIGENS IN PHILADELPHIA-CHROMOSOME-POSITIVE LEUKEMIAS

In chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (AL L) the Ph1 chromosome (22q-) is the most frequent chromosomal aberrati on encountered. At the molecular level the c-abl gene from chr. 9 is t ranslocated to the bcr gene on chr. 22. As a result, a chimeric bcr-ab l gene is generated, which encodes chimeric proteins. Since these prot eins are only expressed in Ph1 positive cells, they are per definition tumor-specific. In this report we describe the reactivity of polyvale nt antisera raised against synthetic peptides corresponding to the tum or-specific bcr-abl junctions. Native chimeric proteins were specifica lly recognized by these junction-specific antisera. Therefore we concl ude that the bcr-abl junctions are antigenically exposed on the chimer ic proteins. We discuss the relevance of these antisera for CML and AL L diagnosis.