The strategy for identifying the genes encoding secretory proteins for which expression is dependent on the cell types or the cell states. In the present study, our strategy was applied to human T lymphocytes. First, SAGE was performed to reveal genes selectively expressed under specific T lymphocyte conditions such as activated Th1, activated Th2, or activated T lymphocytes. Second, the specific genes were collected by using 3′ RACE. Finally, by using a DNA microarray system, the genes encoding secretory proteins were identified by analyzing RNAs from the free ribosomal and the microsomal fraction after equilibrium density–gradient centrifugation.
