Biochemical characterization of huPRR2 and PRR2δ. Da-1 (1), Da-1/PRR2 (2), and Da-1/PRR2δ (3) cell lines were lysed and immunoprecipitated with MoAb R2.477 as described in Materials and Methods. Blots were then incubated with a 1/10,000 rabbit immune serum directed against PRR2 (A), PRR2δ (B), or both (C).  and δ isoforms of PRR2 were indicated and the calculated molecular weights were 64 and 72 kD, respectively. The band at 50 kD corresponds to the heavy chain of MoAb R2.477. Molecular weight markers were from Biolabs.