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Lactoferrin (LTF) is a natural iron-binding protein with a potential for clinical utility in many human immune disorders, including cancer. A fusion of LTF with the Fc domain of IgG2 (FcLTF) was designed with inherent properties of an extended the half-life in circulation. Furthermore, the effects of LTF and FcLTF were assessed for influence on the activity of natural killer (NK) cells isolated from human peripheral blood, on the NK-92 cell line, and on human monocytes. The NK cytotoxic activity induced by LTF and FcLTF was determined against the human leukemia K562 cell line, and also for monocytes, by measuring TNFα and granzyme B production, and in an assay for Jurkat cell viability. Selected gene expression in NK-92 cells and monocytes, induced by LTF and FcLTF, was performed by Real Time PCR. No significant difference was observed in NK-92 cytotoxicity stimulated by LTF and FcLTF. The effects on NK cells isolated from the human peripheral blood were varied, possibly due to the immunoregulatory nature of LTF sensing the immune status of donors. Furthermore, only the FcLTF group strongly stimulated production of TNFα and granzyme B in isolated monocytes. In addition, only supernatants from the monocyte cultures treated with FcLTF decreased the viability of Jurkat cells. The ability of FcLTF to induce TNFα in monocytes was strongly inhibited by anti-CD32 and moderately inhibited by anti-CD14 antibody. Lastly, it was demonstrated that FcLTF, strongly induced expression of PI3K, with subsequent activation of AKT/mTOR signaling pathway. Overall, it was demonstrated that this novel fusion molecule may be a perferred choice for clinical utility than the wild type LTF., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

In this paper, the effect of osteoprotegerin (OPG) on slowing down the resorption process of heterotopically induced bone tissue is described. The induced ossicle is resorbed ex inactivitate. This system mimics osteoporosis in immobilised skeletal bones. Bone induction was achieved in BALB/c mice after the injection of the suspension of 3 x 10(6) HeLa cells into thigh muscle of animals immuno-suppressed by a single dose of hydrocortisone. To slow down the process of resorption we applied OPG and measured quantitatively the effect by weighing the mass of mineral deposited in the induced ossicle after hydrolysis of soft tissues surrounding the induced ossicles. As the effect of application of OPG more than 340-540% of bone mineral is found in the induced ossicles following nine applications of 0.05 mg OPG per mouse, every second day--in comparison to the control animals.