scholarly journals A portfolio of geographically distinct laboratory-adapted Plasmodium falciparum clones with consistent infection rates in Anopheles mosquitoes

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Marga van de Vegte-Bolmer ◽  
Wouter Graumans ◽  
Rianne Stoter ◽  
Geert-Jan van Gemert ◽  
Robert Sauerwein ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Production Capacity ◽  
Infection Intensity ◽  
Anopheles Coluzzii ◽  
Infection Rates ◽  
Malaria Research ◽  
Anopheles Mosquitoes ◽  
Malaria Interventions ◽  
Geographical Locations

Abstract Background The ability to culture Plasmodium falciparum continuously in vitro has enabled stable access to asexual and sexual parasites for malaria research. The portfolio of isolates has remained limited and research is still largely based on NF54 and its derived clone 3D7. Since 1978, isolates were collected and cryopreserved at Radboudumc from patients presenting at the hospital. Here, procedures are described for culture adaptation of asexual parasites, cloning and production of sexual stage parasites responsible for transmission (gametocytes) and production of oocysts in Anopheles mosquitoes. This study aimed to identify new culture-adapted transmissible P. falciparum isolates, originating from distinct geographical locations. Methods Out of a collection of 121 P. falciparum isolates stored in liquid nitrogen, 21 from different geographical origin were selected for initial testing. Isolates were evaluated for their ability to be asexually cultured in vitro, their gametocyte production capacity, and consistent generation of oocysts. Results Out of 21 isolates tested, twelve were excluded from further analysis due to lack of mature gametocyte production (n = 1) or generation of satisfactory numbers of oocysts in mosquitoes (n = 11). Nine isolates fulfilled selection criteria and were cloned by limiting dilution and retested. After cloning, one isolate was excluded for not showing transmission. The remaining eight isolates transmitted to Anopheles stephensi or Anopheles coluzzii mosquitoes and were categorized into two groups with a reproducible mean oocyst infection intensity above (n = 5) or below five (n = 3). Conclusions These new P. falciparum culture-adapted isolates with reproducible transmission to Anopheles mosquitoes are a valuable addition to the malaria research tool box. They can aid in the development of malaria interventions and will be particularly useful for those studying malaria transmission.

scholarly journals A Portfolio of Geographically Distinct Laboratory-adapted Plasmodium Falciparum Clones With Consistent Infection Rates in Anopheles Mosquitoes

2021 ◽  
Author(s):  
Marga van de Vegte-Bolmer ◽  
Wouter Graumans ◽  
Rianne Stoter ◽  
Geert-Jan van Gemert ◽  
Robert Sauerwein ◽  
...  
Keyword(s):  
Geographical Origin ◽  
Production Capacity ◽  
Infection Intensity ◽  
Infection Rates ◽  
Malaria Research ◽  
Anopheles Mosquitoes ◽  
Mature Gametocyte ◽  
Malaria Interventions ◽  
Geographical Locations

Abstract BackgroundThe ability to culture P. falciparum continuously in vitro has enabled stable access to asexual and sexual parasites for malaria research. The portfolio of isolates has remained limited and research is still largely based on NF54 and its derived clone 3D7. Since 1978, isolates were collected and cryopreserved at Radboudumc from patients presenting at the hospital. Here, procedures are described for culture adaptation of asexual parasites, cloning and production of sexual stage parasites responsible for transmission (gametocytes) and production of oocysts in Anopheles mosquitoes. This study aimed to identify new culture adapted transmissible P. falciparum isolates, originating from distinct geographical locations.ResultsOut of a collection of 121 P. falciparum isolates stored in liquid nitrogen, 21 from different geographical origin were selected for initial testing. Isolates were evaluated for their ability to be asexually cultured in vitro, their gametocyte production capacity, and consistent generation of oocysts. Out of 21 isolates tested, twelve were excluded from further analysis due to lack of mature gametocyte production (n = 1) or generation of satisfactory numbers of oocysts in mosquitoes (n = 11). Nine isolates fulfilled selection criteria and were cloned by limiting dilution and retested. After cloning, one isolate was excluded for not showing transmission. The remaining eight isolates transmitted to A. stephensi or A. coluzzii mosquitoes and were categorized into two groups with a reproducible mean oocyst infection intensity above (n = 5) or below five (n = 3). ConclusionsThese new P. falciparum culture adapted isolates with reproducible transmission to Anopheles mosquitoes are a valuable addition to the malaria research tool box. They can aid in the development of malaria interventions and will be particularly useful for those studying malaria transmission.

scholarly journals Artemisinin-resistant Plasmodium falciparum clinical isolates can infect diverse mosquito vectors of Southeast Asia and Africa

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Brandyce St. Laurent ◽  
Becky Miller ◽  
Timothy A. Burton ◽  
Chanaki Amaratunga ◽  
Sary Men ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Southeast Asia ◽  
Artemisinin Resistance ◽  
Rapid Expansion ◽  
Clinical Isolates ◽  
Anopheles Coluzzii ◽  
Mosquito Vectors ◽  
Anopheles Dirus ◽  
Global Spread

Abstract Artemisinin-resistant Plasmodium falciparum parasites are rapidly spreading in Southeast Asia, yet nothing is known about their transmission. This knowledge gap and the possibility that these parasites will spread to Africa endanger global efforts to eliminate malaria. Here we produce gametocytes from parasite clinical isolates that displayed artemisinin resistance in patients and in vitro, and use them to infect native and non-native mosquito vectors. We show that contemporary artemisinin-resistant isolates from Cambodia develop and produce sporozoites in two Southeast Asian vectors, Anopheles dirus and Anopheles minimus, and the major African vector, Anopheles coluzzii (formerly Anopheles gambiae M). The ability of artemisinin-resistant parasites to infect such highly diverse Anopheles species, combined with their higher gametocyte prevalence in patients, may explain the rapid expansion of these parasites in Cambodia and neighbouring countries, and further compromise efforts to prevent their global spread.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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