SYNOPSIS. Although large hemoglobin inclusions are observed in intraerythrocytic Babesia microti parasites, they are absent from parasites freed of hamster red cells by immune lysis with antihamster erythsocyte serum. Babesia microti has no cytostome.
This parasite, therefore, does not appear to feed by phagocytosis of large boluses of hemoglobin, as does Plasmodium. To determine whether Babesia can pinocytose protein, free parasites were fed ferritin in an in vitro system.
Ferritin was taken up from the entire cell surface into narrow channels within 15 min at 37 C. Only merozoites, with their pellicular complex, failed to take up the protein. By 60 min, the ferritin was highly concentrated in many channels and vesicles, which formed interconnecting stacks.
The ferritin-containing channels became associated with membrane whorls of the multimembranous structure. Membrane whorls were also observed in the process of extrusion in samples incubated for longer times. These events may represent steps in the digestion and excretion of the pinocytosed protein.
Empty channels formed when Babesia was fed albumin. The diaminobenzidine reaction for hemoprotein was positive for the channels in both free and intraerythrocytic babesias. The staining reaction was completely inhibited by cyanide, but not at all by aminotriazole. These results further suggest that Babesia pinocytoses hemoglobin in vivo.
Plasmodium lophurae parasites freed of red cells by immune lysis are surrounded by 2 membranes and apparently can ingest ferritin only through the cytostome. Extracellular cytostomal feeding involves both membranes, as it does in vivo.
Ferritin was found in food vacuoles, some of which contained hemoglobin ingested before parasite isolation, connected to or near the cytostome. In both Plasmodium and Babesia low temperature inhibited ferritin uptake."
"A merozoite ...is a daughter cell of a protozoan parasite. Merozoites are the result of asexual reproduction"
"Ferritin is a globular protein complex consisting of 24 protein subunits and is the primary intracellular iron-storage protein in both prokaryotes and eukaryotes, keeping iron in a soluble and non-toxic form. Ferritin that is not combined with iron is called apoferritin."
Just throwing out guesses here, but it seems there is one stage of the Babesia lifecycle that has a decreased ability to uptake ferritin. Perhaps between that and the destruction of red blood cells, there could be periods of heightened ferritin levels?
I am not a scientist or doctor, so this is just layman's brainstorming, here.
Posted by Lymeorsomething (Member # 16359) on :
I see that hemolytic anemia can also cause iron spikes and the non-immune form can be caused by none other than Babesiosis...