The immunosuppressive mini-domain of human lactoferrin.
It has been found that the disulphide-bridged 231-245 pentadecapeptide loop of the lactoferrin (LF) N-lobe contains a region of immunosuppressive activity. The activity resides within a thymopentin-like sequence (Arg-Lys-Pro-Val-Asp) of the loop. Peptides related to the 575-589 loop of the LF C-lobe differ in their immunomodulatory activity from those related to the 231-245 loop. We ascribe this difference to the replacement of the Asp residue in the 231-245 loop by Thr in the 575-589 loop. Two other fragments of LF which were studied, 27-34 and 309-315, do not manifest any activity in the DTH test (cellular immune response), but, on testing in vivo, stimulate the humoral immune response. The 27-34 fragment is related to the bactericidal and immunostimulative region of LF identified by Bellamy et al. [1]. Our results show that the LF molecule contains, not only the known immunostimulating mini-domain, but also a region endowed with immunosuppressive activity.
Siemion
I Z
IZ
Institute of Chemistry, University of Wroclaw, Poland.
Sloń
J
J
Wieczorek
Z
Z
D000595:Amino Acid Sequence; D000818:Animals; D004220:Disulfides / Q000737:chemistry; D006462:Hemolytic Plaque Technique; D006801:Humans; D006968:Hypersensitivity, Delayed; D007159:Immunologic Tests; D007166:Immunosuppressive Agents / Q000737:chemistry* / Q000494:pharmacology*; D007781:Lactoferrin / Q000737:chemistry* / Q000494:pharmacology*; D051379:Mice; D008808:Mice, Inbred CBA; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D016305:Thymopentin / Q000737:chemistry / Q000494:pharmacology
D004220:Disulfides; D007166:Immunosuppressive Agents; D010446:Peptide Fragments; D007781:Lactoferrin; D016305:Thymopentin