Absence of CD45-AP expression in ALST-1 cells. Cell lysates or anti-CD45 immunoprecipitates of ALST-1 and YAC-1 cells were immunoblotted with anti-CD45-AP antibody. The CD45-AP band is indicated by arrows. The prominent band, indicated by an asterisk, that is seen in immunoprecipitates of both cell lines represents immunoglobulin light chains.