Inhibition of proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells by bovine milk caseins and their digests

SUMMARYThe modulating effect of bovine milk casein components and their digests on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced or not induced by mitogens has been studied with a colorimetric assay using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. All the casein components and their digests tested had little mitogenic effect on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells. Intact κ-casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and Peyer's patch cells induced by mitogens such as lipopolysaccharide fromSalmonella typhimurium, concanavalin A, phytohaemagglutinin and pokeweed mitogen. In contrast, intact αsl-casein and β-casein had little effect. κ-Casein had an inhibitory effect after digesti on by pancreatin or trypsin, but not after pepsin or chymotrypsin digestion. Both pancreatin and trypsin digests of αsl-casein and -casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced by mitogens, whereas pepsin and chymotrypsin digests of both caseins were without effect. Moreover, the trypsin digest of each casein component had an inhibitory effect on mouse spleen lymphocyte proliferation in the absence of mitogen. Since trypsin is a major proteinase in pancreatin, the substrate specificity of trypsin seems to be important for the formation of the inhibitory peptides from casein components. These observations suggest that intact κ-casein and some peptides formed from milk casein components by the action of trypsin may suppress the immune responsiveness of neonates.

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Identification of a phosphopeptide in bovine αs1-casein digest as a factor influencing proliferation and immunoglobulin production in lymphocyte cultures

Journal of Dairy Research ◽

10.1017/s0022029998003136 ◽

1998 ◽

Vol 65 (4) ◽

pp. 569-578 ◽

Cited By ~ 52

Author(s):

ISAO HATA ◽

SHIGEKI HIGASHIYAMA ◽

HAJIME OTANI

Keyword(s):

Cell Cultures ◽

Concanavalin A ◽

Inhibitory Effect ◽

Reversed Phase ◽

Mouse Spleen ◽

Peyer’S Patch ◽

Peyer's Patch ◽

Spleen Cells ◽

Rich Region ◽

Immunoglobulin Production

Digestion of bovine αs1-casein with bovine trypsin produced peptide(s) with an inhibitory effect on concanavalin A-induced proliferation of mouse spleen cells. One of these peptides was isolated from the αs1-casein digest following ultrafiltration, hydroxyapatite chromatography and reversed-phase HPLC, and amino acid composition and sequence analyses showed it to be sequence 59–79 from the phosphoserine-rich region of αs1-casein. The isolated peptide significantly inhibited the concanavalin A-induced proliferation of mouse spleen cells and rabbit Peyer's patch cells, whereas it enhanced the lipopolysaccharide- and phytohaemagglutinin-induced proliferation of both cells. The peptide displayed mitogenic activity in the cell cultures without the commercial mitogen, and significantly enhanced immunoglobulin production. Moreover, residues 1–25 from the phosphoserine-rich region of bovine β-casein had a similar effect on the proliferation of mouse spleen cells and rabbit Peyer's patch cells stimulated or not stimulated by the commercial mitogen. These results indicate that caseinophosphopeptides may act as a humoral immunostimulator in cell cultures.

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RESTRICTION OF GENE EXPRESSION IN B LYMPHOCYTES AND THEIR PROGENY

Journal of Experimental Medicine ◽

10.1084/jem.140.2.452 ◽

1974 ◽

Vol 140 (2) ◽

pp. 452-469 ◽

Cited By ~ 26

Author(s):

Patricia P. Jones ◽

Susan W. Craig ◽

John J. Cebra ◽

Leonard A. Herzenberg

Keyword(s):

Lymph Node ◽

B Lymphocytes ◽

Heavy Chain ◽

Plasma Cells ◽

Pokeweed Mitogen ◽

Peyer’S Patch ◽

Peyer's Patch ◽

Experimental Conditions ◽

B Locus

To determine whether or not B lymphocytes are committed to the synthesis of a single immunoglobulin heavy chain isotype during their differentiation into plasma cells, rabbit lymph node and Peyer's patch cells were separated into populations with and without membrane IgM, using a fluorescence-activated cell sorter (FACS). The potential of the µ-bearing (µ+) and non-µ-bearing (µ-) cells to give rise to plasma cells both in vivo after transfer into irradiated recipients and in vitro in the presence of pokeweed mitogen was assessed by immunofluorescence techniques, and the relative proportions of the cytoplasmic Ig-stained cells (CSC) synthesizing each class of heavy chains were determined. Most of the CSC arising in vitro from µ-bearing lymph node and Peyer's patch cells contained IgM; all IgM CSC appeared to be derived from µ+ cells. Peyer's patch lymphocytes, however, did not generate IgM CSC after cell transfer and thus may be functionally different from lymph node µ+ cells. It was found also that nearly all of the many IgA CSC generated by Peyer's patch lymphocytes either in culture or after transfer were derived from µ- cells. Further fractionation of these µ- cells with the FACS after they had been membrane stained with anti-b locus allotype reagents revealed that the precursors of IgA CSC belong to a minor population of cells which do have b locus light chain determinants on their membranes, although they do not have detectable µ-chains. These cells are not found in lymph nodes. Although the majority of Peyer's patch and lymph node cells were found to be precommitted to the synthesis of a single heavy chain isotype, a small proportion of cells may not be similarly restricted. Some of the CSC with membrane IgM were found to contain cytoplasmic IgA or IgG. In addition, µ+ populations did give rise to low numbers of IgA and IgG CSC. The implications of these results, obtained under experimental conditions, on the normal differentiation of B lymphocytes in situ are discussed.

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