Immunostimulation effects of proteose-peptone component 3 fragment on human hybridomas and peripheral blood lymphocytes

Biochim Biophys Acta. 2005 Sep 15;1725(2):233-40. doi: 10.1016/j.bbagen.2005.05.008.


Fat-free bovine milk fermented by 12 kinds of lactic acid bacteria and yeast enhanced monoclonal antibody production of human hybridoma HB4C5 cells 2.8-fold in serum-free medium. Immunoglobulin production of human peripheral blood lymphocytes (PBL) was also stimulated in vitro. IgM and IgG production of human PBL was accelerated up to 2.8-fold and 5.4-fold, respectively. Interferon-gamma production of human PBL was also accelerated 6.0-fold by 50 microg/ml of the fermented milk. However, interleukin-4 production of PBL was not affected, and tumor necrosis factor-alpha production was suppressed. The activity was enhanced 2.5-fold by the thermal treatment for 30 min at 65 degrees C and was completely lost by trypsin digestion. The findings suggested that the active substance in the fermented milk was heat stable protein. Gel-filtration and the SDS-PAGE analysis revealed that the molecular weight of the active substance was estimated as 19.0 kDa, which was not detected in fat-free bovine milk before fermentation. N-terminal amino acid sequence of the 19.0 kDa protein was highly homologous to proteose-peptone component 3 (PP3). Since molecular weight of PP3 is 28 kDa, it is suggested that the 19.0 kDa protein is derived from degradation of PP3 during fermentation of fat-free milk. Moreover, PP3 purified from fat-free milk also enhanced IgM production of HB4C5 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / chemistry
  • Adjuvants, Immunologic / pharmacology
  • Animals
  • Caseins / chemistry
  • Caseins / immunology*
  • Caseins / pharmacology*
  • Cattle
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Glycoproteins / chemistry
  • Glycoproteins / immunology*
  • Glycoproteins / pharmacology*
  • Humans
  • Hybridomas / drug effects*
  • Hybridomas / immunology*
  • Immunoglobulin M / immunology*
  • Lymphocytes / drug effects*
  • Lymphocytes / immunology*
  • Milk Proteins / chemistry
  • Milk Proteins / immunology
  • Milk Proteins / pharmacology
  • Peptide Fragments / chemistry
  • Peptide Fragments / immunology*
  • Peptide Fragments / pharmacology*


  • Adjuvants, Immunologic
  • Caseins
  • Glycoproteins
  • Immunoglobulin M
  • Milk Proteins
  • PP3 protein, Bos taurus
  • Peptide Fragments