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Safety and feasibility of apheresis to harvest and concentrate parasites from subjects with induced blood stage Plasmodium vivax infection
Anand ODEDRA
Liverpool School of Tropical Medicine
Corresponding Author
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This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Malaria Journal.
Background In the absence of a method to culture Plasmodium vivax , the only way to source parasites is ex vivo . This hampers many aspects of P. vivax research. We assessed the safety of apheresis, a method for selective removal of specific components of blood as a means of extracting and concentrating P. vivax parasites.
Methods An iterative approach was employed across four non-immune healthy human subjects in separate cohorts. All four subjects were inoculated with ~564 blood stage P. vivax parasites (HMP013- Pv ) and subjected to apheresis 10 to 11 days later. Blood samples collected during apheresis were tested for the presence and concentration of P. vivax parasites by microscopy, flow cytometry, 18S rDNA qPCR for total parasites, and pvs2 5 qRT-PCR for female gametocyte transcripts. Safety was determined by monitoring adverse events. Malaria transmission to mosquitoes was assessed by membrane feeding assays.
Results There were no serious adverse events and no significant safety concerns. Apheresis concentrated asexual parasites by up to 4.9-fold (range: 0.9 - 4.9-fold) and gametocytes by up to 1.45-fold (range: 0.38 - 1.45-fold) compared to pre-apheresis densities. No single haematocrit layer contained >40% of all the recovered P. vivax asexual parasites. Ex vivo concentration of parasites by percoll gradient centrifugation of whole blood achieved greater concentration of gametocytes than apheresis. Mosquito transmission was enhanced by up to 5-fold in a single apheresis sample compared to pre-apheresis.
Conclusion The modest level of parasite concentration suggests that the use of apheresis may not be an ideal method for harvesting P. vivax parasites.
Trial Registration Australia New Zealand Clinical Trials Registry (ANZCTR) Trial ID: ACTRN12617001502325 registered on 19th October 2017. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373812
Keywords
malaria, plasmodium vivax, apheresis, parasite concentration
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Editor invited
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This preprint is under consideration at Malaria Journal. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Safety and feasibility of apheresis to harvest and concentrate parasites from subjects with induced blood stage Plasmodium vivax infection
Anand ODEDRA
Liverpool School of Tropical Medicine
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
Published
On 14 Jan, 2021
No community comments so far
Editorial decision: Accept
On 03 Jan, 2021
Editor assigned
On 02 Jan, 2021
Submission checks complete
On 02 Jan, 2021
Editor invited
On 02 Jan, 2021
Version (no preprint)
Posted 29 Dec, 2020
Editor assigned
On 29 Dec, 2020
Editorial decision: Minor Revision
On 29 Dec, 2020
Submission checks complete
On 29 Dec, 2020
Editor invited
On 29 Dec, 2020
This version was not preprinted
Version (no preprint)
Posted 26 Dec, 2020
Editorial decision: Minor Revision
On 26 Dec, 2020
Editor assigned
On 23 Dec, 2020
Submission checks complete
On 23 Dec, 2020
Editor invited
On 23 Dec, 2020
This version was not preprinted
Version 1
Posted 03 Apr, 2020
No comments provided
Review #1 received
Received 30 Apr, 2020
Reviewer #1 agreed
On 09 Apr, 2020
Reviewers invited
Invitations sent on 08 Apr, 2020
Editor assigned
On 03 Apr, 2020
Editor invited
On 02 Apr, 2020
Submission checks complete
On 01 Apr, 2020
First submitted
On 31 Mar, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Infectious Diseases
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Malaria Journal.
Background In the absence of a method to culture Plasmodium vivax , the only way to source parasites is ex vivo . This hampers many aspects of P. vivax research. We assessed the safety of apheresis, a method for selective removal of specific components of blood as a means of extracting and concentrating P. vivax parasites.
Methods An iterative approach was employed across four non-immune healthy human subjects in separate cohorts. All four subjects were inoculated with ~564 blood stage P. vivax parasites (HMP013- Pv ) and subjected to apheresis 10 to 11 days later. Blood samples collected during apheresis were tested for the presence and concentration of P. vivax parasites by microscopy, flow cytometry, 18S rDNA qPCR for total parasites, and pvs2 5 qRT-PCR for female gametocyte transcripts. Safety was determined by monitoring adverse events. Malaria transmission to mosquitoes was assessed by membrane feeding assays.
Results There were no serious adverse events and no significant safety concerns. Apheresis concentrated asexual parasites by up to 4.9-fold (range: 0.9 - 4.9-fold) and gametocytes by up to 1.45-fold (range: 0.38 - 1.45-fold) compared to pre-apheresis densities. No single haematocrit layer contained >40% of all the recovered P. vivax asexual parasites. Ex vivo concentration of parasites by percoll gradient centrifugation of whole blood achieved greater concentration of gametocytes than apheresis. Mosquito transmission was enhanced by up to 5-fold in a single apheresis sample compared to pre-apheresis.
Conclusion The modest level of parasite concentration suggests that the use of apheresis may not be an ideal method for harvesting P. vivax parasites.
Trial Registration Australia New Zealand Clinical Trials Registry (ANZCTR) Trial ID: ACTRN12617001502325 registered on 19th October 2017. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373812
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6