title: Antibodies against the amino-terminal portion of pro-enkephalin inhibit DNA synthesis in human peripheral mononuclear cells.
abstract: Pro-enkephalin (PENK) mRNA and PENK-derived peptides have been reported in lymphocytes, monocytes, and macrophages. Met-enkephalin (ME) and/or synenkephalin (SYN)-containing peptides are produced and released by human peripheral blood lymphocytes (HPBL) activated with phytohemagglutinin (PHA). Furthermore, SYN (PENK 1-70) was cleaved to low-molecular-mass peptides in HPBL. In this work we studied the effect of a mouse monoclonal antibody (mAb) and a rabbit antiserum (pAb) against the C-terminal portion of SYN on DNA synthesis in PHA-activated HPBL. [3H]Thymidine incorporation into HPBL incubated with 0.1 microgram/ml of PHA was tested in the presence of different concentrations of mAb immunoglobulin (Ig) G or different dilutions of pAb. mAb induced a concentration-dependent decrease of [3H]thymidine incorporation into HPBL: 7%, 19%, 28%, and 35% of inhibition was observed with 0.1, 1, 1.5, and 2 micrograms IgG, respectively, reaching values of 65% with 10 micrograms IgG. Similarly, pAb dilutions of 1/500, 1/1000, 1/2000 and 1/4000 inhibited DNA synthesis by 63%, 61%, 43%, and 30%, respectively. The inhibitory effect of mAb and pAb was specific since it was not produced by non-immune mouse IgG or several non-immune rabbit sera and was completely reversed by 1 microM of the synthetic peptide [Tyr63](syn 63-70) synenkephalin. These results suggest that low-molecular-mass SYN-derived peptides released by PHA-activated HPBL may participate in the proliferative response of these cells. This is further evidence that the non-opioid portion of PENK--that is, SYN-derived peptides--may be involved in tissue development.
authors.affiliation: Instituto de Fisiología, Universidad Autónoma de Puebla, Mexico.
authors.forename: M R
authors.initials: MR
authors.lastname: Padrós
authors.forename: F
authors.initials: F
authors.lastname: Saravia
authors.forename: O
authors.initials: O
authors.lastname: Vindrola
mesh_terms: D000595:Amino Acid Sequence; D002455:Cell Division; D004745:Enkephalins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007158:Immunologic Techniques; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000166:cytology*; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D015213:Neuroimmunomodulation; D011498:Protein Precursors / Q000737:chemistry / Q000276:immunology*
chemical_list: D004745:Enkephalins; D011498:Protein Precursors; C029992:proenkephalin; C036693:synenkephalin