Analysis of the Relationship between Radiosensitivity and Cell Age in Proliferating Mouse Spleen Lymphocytes

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.

Download Full-text

Distribution of Glycerophospholipids in the Adult Human Lens

Biomolecules ◽

10.3390/biom8040156 ◽

2018 ◽

Vol 8 (4) ◽

pp. 156 ◽

Cited By ~ 2

Author(s):

Jo Seng ◽

Jessica Nealon ◽

Stephen Blanksby ◽

Todd Mitchell

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometry Imaging ◽

Imaging Mass Spectrometry ◽

Human Lens ◽

Limited Data ◽

Outer Cortex ◽

Adult Human ◽

Cell Age ◽

Human Lenses ◽

The Relationship

In humans, the age of fibre cells differs across the ocular lens, ranging from those formed before birth in the core of the lens to those formed just prior to death in the outer cortex. The distribution of glycerophospholipids in the adult human lens should reflect this range; however, limited data currently exists to confirm this hypothesis. Accordingly, this study aimed to determine the distribution of glycerophospholipids in adult human lens using mass spectrometry imaging. To achieve this, 20-µm thick slices of two human lenses, aged 51 and 67 were analysed by matrix-assisted laser desorption ionisation imaging mass spectrometry. The data clearly indicate that intact glycerophospholipids such as phosphatidylethanolamine, phosphatidylserine, and phosphatidic acid are mainly present in the outer cortex region, corresponding to the youngest fibre cells, while lyso-phosphatidylethanolamine, likely produced by the degradation of phosphatidylethanolamine, is present in the nucleus (older fibre cells). This study adds further evidence to the relationship between fibre cell age and glycerophospholipid composition.

Download Full-text