Peptides related to FKBP 39-45 loop possess immunostimulative potency

151 Taking into account the sequential homology existing between thymopoiet in II, the DNA-binding domain of p53 protein and FKBP (FK-506 binding prote in), a series of fragments of human and bovine FKBP containing a fragment S er(39)-Pro(45) were synthesized. In the humoral in vitro test all the pepti des act as stimulators. Whereas in the in vivo test peptides derived from b ovine FKBP show an immunostimulative and those from human FKBP an immunosup pressive activity. However, after blocking the Asp residue by a Bzl group t he peptide V appears to be an immunostimulator. The data obtained suggest t hat these peptides can influence the immune system by blocking the FKBP rec eptor. (C) 1998 Elsevier Science Inc.