Abstract
Tumor immunotherapy has attracted many attentions in recent years because of
its high specificity. However, the use of immunotherapy is hampered by the lack
of defined target tumor antigens. T351 gene, a novel tumor associated gene
identified by mRNA differential display, encodes a transmembrane protein. We
found that T351 is overexpressed in tumor tissues and tumor cell lines at both
mRNA and protein levels by quantitative reverse transcription-PCR,
immunohistochemistry and flow cytometry analyses, respectively. We also show
that the extracellular portion of T351 protein termed T351pro.philic specifically
activate CTLs to lyse tumor cell targets. In addition, a monoclonal antibody raised
against T351pro.philic (McAb C1-1) induced murine macrophages to kill tumor
cells effectively both in vitro and in vivo. These results suggest that T351 protein
is a novel tumor associated antigen.