Lectin activity and distribution of chicken lactose lectin I in the extracellular matrix of the chick developing kidney

A lectin activity inhibitable by thiodigalactose, N-acetyllactosamine, lactulose, lactose and by an antibody raised against CLL I (chicken-lactose lectin I) has been investigated in the chick embryo developing kidney. At post-induction stages this activity was found in both mesonephros and metanephros. In immunofluorescence and immunoelectron microscopy, the extracellular distribution of CLL I was similar in the mesonephros and the metanephros. The lectin was never found intracellularly; cultured kidney cells did not express any endogenous lectin but were rich in lectin-receptor sites, which led to the hypothesis that CLL I is not produced in situ but could be adsorbed on renal cells. Potential physiological roles for embryonic lectins are discussed.