[The role of lactotransferrin in the molecular mechanisms of antibacterial defense].

Lactotransferrin is involved in the antibacterial defence of the host by virtue of its reversible iron-binding capacity. On the one hand, it participates in different molecular mechanisms displayed by immunocompetent cells which are known to synthesize or recognize the lactotransferrin. For instance, 1) during inflammation, apolactotransferrin released by the neutrophils captures the iron from serotransferrin which is accumulated by the macrophages, by means of their lactotransferrin membrane receptors; 2) lactotransferrin is an important component in the microbicidal activity of neutrophils by regulating the hydroxyl radical production; 3) lactotransferrin acts as a regulator of myelopoiesis by modulating activity of the colony stimulating factors; 4) lactotransferrin could be involved in the control mechanism of lymphoid cell migration. On the other hand, lactotransferrin participates to the non-specific local secretory immunity by being involved in antibacterial mechanisms together with secretory immunoglobulins sIgA and lysozyme. The different aspects of the participation of the lactotransferrin in the cellular and secretory mechanisms of antibacterial defence of the host show that the lactotransferrin plays a predominant role in the local immunity of any mucosa.