Interaction between human lactoferrin and B lymphocytes

Abstract

Our previous studies demonstrated that B lymphocytes incorporated human lactoferrin (LF) and then released it to an extracellular medium. We did competition experiments for better understanding of the interaction between LF and B lymphocytes, using a reverse hemolytic plaque forming assay. Competition between human and bovine LF reduced the number of plaque forming cells (PFC), but human transferrin (TF) showed no inhibitory effect on the PFC counts. These suggested that the receptor on B lymphocytes to human LF did not share with TF but bovine LF. The competition between a synthetic N-terminal nonapeptide of human LF (Gly-Arg-Arg-Arg-Arg-Ser-Val-Gln-Trp) and human LF demonstrated reduced number of PFC dose-dependently. Mild tryptic human LF also reduced the human LFPFC counts, although removal of the C-terminal region did not affect the PFC counts. From these results, we concluded that highly cationic areas of human LF, such as N-terminal, accounted for the interaction with B lymphocytes.