Limits...
Refractoriness of eryptotic red blood cells to Plasmodium falciparum infection: a putative host defense mechanism limiting parasitaemia.

Totino PR, Daniel-Ribeiro CT, Ferreira-da-Cruz Mde F - PLoS ONE (2011)

Bottom Line: Schizont parasitized RBC concentrated by magnetic separation were cultured with eryptotic RBC obtained by ionomycin treatment and, then, parasite growth was evaluated in Giemsa-stained thin blood smears.While parasites infected and developed normally in control non-eryptotic RBC, cultures performed with eryptotic RBC had a marked decrease in parasitaemia.It was noteworthy a great number of free merozoites in eryptotic RBC cultures, indicating that these cells were not susceptible to invasion.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Malaria Research, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brasil.

ABSTRACT
Recently, we have described that apoptosis-like process of red blood cells (RBC) - eryptosis - in malaria is not restricted to parasitized cells, occurring also in non-parasitized RBC (nRBC). Besides to pathogenic proprieties, apoptosis also participates in the innate defense trough restriction of intracellular pathogens propagation. In the present study, we investigated the capacity of P. falciparum parasites to infect eryptotic RBC. Schizont parasitized RBC concentrated by magnetic separation were cultured with eryptotic RBC obtained by ionomycin treatment and, then, parasite growth was evaluated in Giemsa-stained thin blood smears. While parasites infected and developed normally in control non-eryptotic RBC, cultures performed with eryptotic RBC had a marked decrease in parasitaemia. It was noteworthy a great number of free merozoites in eryptotic RBC cultures, indicating that these cells were not susceptible to invasion. We suggest that although eryptosis could be involved in malaria pathogenesis, it could also acting protectively by controlling parasite propagation.

Show MeSH

Related in: MedlinePlus

Induction of RBC eryptosis.RBC (A, R1) were incubated at 37°C for 4 h at 2% hematocrit in presence (gray) or absence (black line) of ionomycin (1 µM) and, then, induction of eryptosis was verified by forward scatter measurement (B) and annexin V-PE staining (C).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3198779&req=5

pone-0026575-g001: Induction of RBC eryptosis.RBC (A, R1) were incubated at 37°C for 4 h at 2% hematocrit in presence (gray) or absence (black line) of ionomycin (1 µM) and, then, induction of eryptosis was verified by forward scatter measurement (B) and annexin V-PE staining (C).

Mentions: It is actually known that programmed cell death is not a mechanism exclusive of nucleated cells, occurring also in enucleated cells as RBC. A variety of compounds and pathological conditions inductors of eryptosis – process characterized by Ca2+ influx, protease activation, membrane blebbing, cell shrinkage and PS exposure – has been described [14]. In the present study, the capacity of P. falciparum parasites to invade and develop into eryptotic RBC was tested using a population of eryptotic RBC obtained through treatment with ionomycin, which was able to induce eryptosis in nearly all treated RBC population (Figure 1).


Refractoriness of eryptotic red blood cells to Plasmodium falciparum infection: a putative host defense mechanism limiting parasitaemia.

Totino PR, Daniel-Ribeiro CT, Ferreira-da-Cruz Mde F - PLoS ONE (2011)

Induction of RBC eryptosis.RBC (A, R1) were incubated at 37°C for 4 h at 2% hematocrit in presence (gray) or absence (black line) of ionomycin (1 µM) and, then, induction of eryptosis was verified by forward scatter measurement (B) and annexin V-PE staining (C).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198779&req=5

pone-0026575-g001: Induction of RBC eryptosis.RBC (A, R1) were incubated at 37°C for 4 h at 2% hematocrit in presence (gray) or absence (black line) of ionomycin (1 µM) and, then, induction of eryptosis was verified by forward scatter measurement (B) and annexin V-PE staining (C).
Mentions: It is actually known that programmed cell death is not a mechanism exclusive of nucleated cells, occurring also in enucleated cells as RBC. A variety of compounds and pathological conditions inductors of eryptosis – process characterized by Ca2+ influx, protease activation, membrane blebbing, cell shrinkage and PS exposure – has been described [14]. In the present study, the capacity of P. falciparum parasites to invade and develop into eryptotic RBC was tested using a population of eryptotic RBC obtained through treatment with ionomycin, which was able to induce eryptosis in nearly all treated RBC population (Figure 1).

Bottom Line: Schizont parasitized RBC concentrated by magnetic separation were cultured with eryptotic RBC obtained by ionomycin treatment and, then, parasite growth was evaluated in Giemsa-stained thin blood smears.While parasites infected and developed normally in control non-eryptotic RBC, cultures performed with eryptotic RBC had a marked decrease in parasitaemia.It was noteworthy a great number of free merozoites in eryptotic RBC cultures, indicating that these cells were not susceptible to invasion.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Malaria Research, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brasil.

ABSTRACT
Recently, we have described that apoptosis-like process of red blood cells (RBC) - eryptosis - in malaria is not restricted to parasitized cells, occurring also in non-parasitized RBC (nRBC). Besides to pathogenic proprieties, apoptosis also participates in the innate defense trough restriction of intracellular pathogens propagation. In the present study, we investigated the capacity of P. falciparum parasites to infect eryptotic RBC. Schizont parasitized RBC concentrated by magnetic separation were cultured with eryptotic RBC obtained by ionomycin treatment and, then, parasite growth was evaluated in Giemsa-stained thin blood smears. While parasites infected and developed normally in control non-eryptotic RBC, cultures performed with eryptotic RBC had a marked decrease in parasitaemia. It was noteworthy a great number of free merozoites in eryptotic RBC cultures, indicating that these cells were not susceptible to invasion. We suggest that although eryptosis could be involved in malaria pathogenesis, it could also acting protectively by controlling parasite propagation.

Show MeSH
Related in: MedlinePlus