GROWTH-INHIBITORY EFFECTS OF BOVINE LACTOFERRIN TO TOXOPLASMA-GONDII PARASITES IN MURINE SOMATIC-CELLS

Lactoferrin (LF) is known to have broad spectrum antimicrobial propert ies. In regards to its defense mechanism against parasitic infection, it has shown phagocytic activity in the destruction of amastigotes, an intracellular parasitic form of Trypanosoma cruzi in macrophages. The effect of bovine lactoferrin on the intracellular growth Toxoplasma g ondii parasites was examined in murine macrophage and embryonal cells. Co-cultures of host cells with the parasites were supplemented with e ither lactoferrin, apo-lactoferrin, holo-lactoferrin or transferrin in the culture media for varying periods. The growth activity of intrace llular parasites in the host cells was determined by the measurement o f selective incorporation of H-3-uracil. Supplement of lactoferrin had no effect on the penetration activity of the parasites, while develop ment of intracellular parasites was inhibited linearly in concentratio n of lactoferrin. Supplement of apo-lactoferrin and holo-lactoferrin, but not transferrin showed similar effects. These suggest that lactofe rrin induces the inhibitory effects on the development of intracellula r parasites. Pretreatment of lactoferrin to the macrophages, however, did not show any inhibitory effects. Whereas, mouse embryonal cells pr eincubated with lactoferrin suppressed the intracellular growth. Thus, the action of lactoferrin to macrophages would be different from that of mouse embryonal cells.