Neutrophil lactoferrin content: Variation among mammals

Abstract

Lactoferrin (Lf) in blood and/or marrow neutrophils was semiquantified using indirect immunofluorescence technique in nine mammalian species. Neutrophil iron-binding reactivity (NFeBR), which corresponds primarily to Lf, was also visualized and semiquantified using functional cytochemical (FeNTA-AF) technique at the light microscopic level in these nine and in an additional fifteen mammalian species, and in selected species at the ultrastructural level. Neutrophil immunoreactive Lf was positively correlated with total cellular and granule content of NFeBR among these nine species, and with previously reported concentrations of neutrophil Lf quantified by radioimmunoassay. Relative levels of Lf in neutrophil extracts from rat, hamster, and human were confirmed using SDS-polyacrylamide gel electrophoresis and immunoblotting. Relatively high levels of immunoreactive neutrophil Lf and/or NFeBR were observed in carnivores (ten species) and primates (six species). Among rodents (five species), the levels were variable, and the artiodactyls (four species) studied had low levels. These results demonstrate that neutrophil Lf levels vary widely among mammalian species. In addition, FeNTA-AF technique provides a rapid means of evaluating animals for relative quantities of neutrophil Lf.

Cell-surface lactoferrin as a marker for degranulation of specific granules in bovine neutrophils

“…In addition to flow cytometric applications, FITC-conjugated BL97 also was useful for immunofluorescence microscopy of bovine neutrophils. As would be expected for a granular protein, lactoferrin staining was distributed throughout the neutrophil cytoplasm, a result consistent with that described for bovine neutrophils by Barton et al 45 Using light microscopy, discrete granular structure was not visible at the available resolution. Using this method, PMAtreated cells stained similarly to untreated cells, although there was a wider range of fluorescent intensities (data not shown).…”

“…Lactoferrin can be detected on the surface of human neutrophils, 34,53 and the relative amount of cell-surface lactoferrin increases with PMA stimulation. 53 Similar to human neutrophils, bovine neutrophils contain lactoferrin, although reportedly at lower amounts than in human neutrophils, 45 and lactoferrin has been used as a marker of specific granules in bovine neutrophils. 21 Recently, we documented that bovine neutrophils also have cell-surface lactoferrin and that the relative amount of surfaceassociated lactoferrin increases with PAF stimulation.…”

What Is the Evolutionary Fingerprint in Neutrophil Granulocytes?

“…The lactoferrin, primarily stored in secondary granules, shows considerable variations among mammals. Even though it was detected in all investigated species, the amounts in carnivores and primates were higher than in herbivores [104]. The consequent staining was the least in cows and in size the largest in rabbits.…”

“…The consequent staining was the least in cows and in size the largest in rabbits. Interestingly, milk lactoferrin concentrations correspond to the amounts in neutrophils of the respective species [104]. Located in the matrix of azurophil granules of all investigated species is β-glucuronidase.…”

Diverse Mechanisms of Antimicrobial Activities of Lactoferrins, Lactoferricins, and Other Lactoferrin-Derived Peptides

“…Lower concentrations of lactoferrins are found in other exocrine secretions. Additionally, for neutrophils, the lactoferrin concentrations vary across mammalian species [ 7 ], while in humans, the structure of the neutrophil lactoferrin is identical to that from milk [ 8 ].…”