Purified plasmodium and vaccine compositions
Inventors
Sim, B. Kim Lee • Li, Minglin • Stafford, Richard E. • Hoffman, Stephen L.
Assignees
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Publication Number
US-9616115-B2
Publication Date
2017-04-11
Expiration Date
Abstract
Disclosed are substantially purified Plasmodium sporozoites and preparations of Plasmodium sporozoites substantially separated from attendant non-sporozoite material, where the preparations of Plasmodium sporozoites have increasing levels of purity. Vaccines and pharmaceutical compositions comprising purified Plasmodium sporozoites are likewise provided. Methods of purifying preparations of Plasmodium sporozoites are also provided.
Core Innovation
The document discloses substantially purified Plasmodium sporozoites, including attenuated or pathogenic sporozoites, separated from attendant non-sporozoite material with increasing purity. The purified sporozoites are provided as sterile or aseptic preparations and in vaccine or pharmaceutical compositions.
The document provides a multi-stage size-exclusion and filtration workflow for purifying live Plasmodium sporozoites. The purification includes use of matrix and track-etched membrane filters to remove salivary gland attendant material to defined low levels, and it assesses purification quantitatively using SGM-ELISA.
The document also describes purifying pathogenic sporozoites for use in drug or vaccine efficacy testing, including volunteer challenge while reducing contamination risk. Potency and safety concepts are addressed, and in vitro potency is discussed using PfLSA-1 expression in human hepatocyte cultures.
Claims Coverage
The document identifies two independent claims covering assessment methods for an antimalarial vaccine and an antimalarial drug. Both claims rely on challenging a human subject with purified, pathogenic Plasmodium-species parasites in a composition that contains less than 85 ng of attendant material per 25,000 sporozoites, followed by evaluating the subject for malaria signs, symptoms, or pathology.
Assessing antimalarial vaccine effectiveness using purified pathogenic Plasmodium-species parasites with low attendant material
A method of assessing the effectiveness of an antimalarial vaccine in a human subject previously treated with the antimalarial vaccine, comprising challenging the subject with one or more doses of a composition comprising purified, pathogenic Plasmodium-species parasites, wherein the composition comprises less than 85 ng of attendant material per 25,000 sporozoites, and evaluating the subject for signs, symptoms, or pathology of malaria.
Assessing antimalarial drug effectiveness using purified pathogenic Plasmodium-species parasites with low attendant material
A method of assessing the effectiveness of an antimalarial drug in a human subject, comprising challenging the subject with one or more doses of a composition comprising purified, pathogenic Plasmodium-species parasites, wherein the composition comprises less than 85 ng of attendant material per 25,000 sporozoites, administering the antimalarial drug to the subject, and evaluating the subject for signs, symptoms, or pathology of malaria.
Across the independent claims, the main inventive concept is the use of purified pathogenic Plasmodium-species parasites with a defined low level of attendant material per 25,000 sporozoites to enable evaluation of vaccine or drug effectiveness in a human subject, with outcomes assessed as malaria signs, symptoms, or pathology.
Stated Advantages
Reduces risks from contamination by using purified sporozoites separated from attendant non-sporozoite material.
Documented Applications
Assessing the effectiveness of an antimalarial vaccine in a human subject previously treated with the antimalarial vaccine using a challenge with purified, pathogenic Plasmodium-species parasites.
Assessing the effectiveness of an antimalarial drug in a human subject by challenging with purified, pathogenic Plasmodium-species parasites, administering the antimalarial drug, and evaluating malaria signs, symptoms, or pathology.
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