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Elevated levels of chemokines have been observed in various diseases of the CNS. Little is known, however, about how these chemokines affect parenchymal cells of the CNS. The current studies examine astrocyte chemotaxis to the mouse chemokine macrophage inflammatory protein-1alpha (MIP-1alpha). Murine astrocytes demonstrate directed migration along a chemical gradient in response to 10(-10)-10(-8) M MIP-1alpha. Peak chemotactic responses are noted at 10(-9) M. MIP-1alpha-induced astrocyte migration is specifically inhibitable with pertussis toxin, suggesting a role for Galphai proteins in the signaling process. RT-PCR and in situ hybridization were used to identify expression of the murine CCR1 MIP-1alpha receptor on astrocytes. Astrocytes contain mRNA for CCR1, but messages for CCR4 and the orphan chemokine receptor MIP-1alphaR-like#1 were not detected. The combined results suggest that a functional chemokine receptor is expressed on resident cells of the CNS. We speculate that the interactions of chemokines with astrocytes are involved in inflammatory reactions of the CNS.

ABSTRACT. Sporozoites of Toxoplasma gondii preincubated with lactoferricin showed decreased activity in penetration of mouse embryonal cells. Mice inoculated with 10 5 sporozoites preincubated with lactoferricin showed a higher survival rate than those inoculated with the same number of untreated sporozoites. Likewise, sporozoites of Eimeria stiedai preincubated with lactoferricin also showed decreased activity in penetration of rabbit hepatobiliary cells. Rabbits inoculated with 10 5 sporozoites preincubated with lactoferricin shed fewer oocysts than those inoculated with the same number of untreated sporozoites. These results indicate that lactoferricin is effective to reduce the infectivity of sporozoites of Toxoplasma gondii and Eimeria stiedai. Toxoplasma gondii (T. gondii), an obligatory intracellular parasitic protozoan is an intestinal coccidium of felids. In intermediate hosts, the parasites multiply as tachyzoites which cause host cell rupture and as bradyzoites which form tissue cysts. In feline intestinal epithelium, the parasites develop through a sexual cycle, resulting in oocyst shedding. The oocysts are resistant to environmental stress and undergo sporogony to form sporozoites which have infectivity in the intermediate and definitive hosts.Lactoferricin (Lfcin) generated by pepsin digestion of bovine lactoferrin (Lf) is composed of 25 amino acid residues, and is known as an antimicrobial peptide able to damage microbial membranes directly [1,2]. Previous studies have shown that Lfcin has parasiticidal effects against tachyzoites and bradyzoites/cysts of T. gondii [7]. Peroral administration of Lfcin has been shown to have a protective effect against infection by extra-intestinal stage parasites [4]. Whether Lfcin has such an inhibitory effect against sporozoites, however, has not yet been investigated.In the present study, we examined whether Lfcin is effective to reduce the infectivity of sporozoites of T. gondii. In order to examine whether the actions of Lfcin are specific for T. gondii or whether it has similar inhibitory effects against other coccidian sporozoites, in similar experiments we tested its effect on sporozoites of Eimeria stiedai (E. stiedai) which develops in hepatobiliary cells of rabbits and causes intensive obstructive jaundice due to oocyst shedding.Bovine lactoferricin was prepared from bovine lactoferrin by the method of Bellamy et al. [1]. For experiments, Lfcin was dissolved at a concentration of 2 mg/ml in Dulbecco's modified Eagle's medium containing 1% bovine serum albumin (D-MEM1%BSA) just before use.Rabbit hepatobiliary cells (RHC) were harvested from the liver of rabbits as described by Njenga et al. [5]. Mouse embryonal cells (MEC) were prepared as described elsewhere [6]. Both types of cells were cultured in D-MEM containing 10% fetal bovine serum (D-MEM10%FBS). For experiments, the cells were removed by treatment with 0.025% trypsin in phosphate-buffered saline (PBS). A 0.2 ml portion of the cell suspension, at a cell concentration of 2 × 10 4 cells/ml, was app...

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