Pre-clinical evaluation of a whole-parasite vaccine to control human babesiosis

Babesia spp. are tick-transmitted intra-erythrocytic protozoan parasites that infect humans and animals, causing a flu-like illness and hemolytic anemia. There is currently no human vaccine available. People most at risk of severe disease are the elderly, immunosuppressed, and asplenic individuals....

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Bibliographic Details
Published in:	Cell host & microbe 2021-06, Vol.29 (6), p.894-903.e5
Main Authors:	Al-Nazal, Hanan A., Cooper, Emily, Ho, Mei Fong, Eskandari, Sharareh, Majam, Victoria, Giddam, Ashwini Kumar, Hussein, Waleed M., Islam, Md. Tanjir, Skwarczynski, Mariusz, Toth, Istvan, Kumar, Sanjai, Zaid, Ali, Batzloff, Michael, Stanisic, Danielle I., Good, Michael F.
Format:	Article
Language:	eng
Subjects:	B. divergens B. microti Babesia heterologous protection immunity T cells vaccine whole parasite vaccine
Online Access:	Get full text
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Summary:	Babesia spp. are tick-transmitted intra-erythrocytic protozoan parasites that infect humans and animals, causing a flu-like illness and hemolytic anemia. There is currently no human vaccine available. People most at risk of severe disease are the elderly, immunosuppressed, and asplenic individuals. B. microti and B. divergens are the predominant species affecting humans. Here, we present a whole-parasite Babesia vaccine. To establish proof-of-principle, we employed chemically attenuated B. microti parasitized red blood cells from infected mice. To aid clinical translation, we produced liposomes containing killed parasite material. Vaccination significantly reduces peak parasitemia following challenge. B cells and anti-parasite antibodies do not significantly contribute to vaccine efficacy. Protection is abrogated by the removal of CD4+ T cells or macrophages prior to challenge. Importantly, splenectomized mice are protected by vaccination. To further facilitate translation, we prepared a culture-based liposomal vaccine and demonstrate that this performs as a universal vaccine inducing immunity against different human Babesia species. [Display omitted] •Babesia microti is an emerging human pathogen of red cells and is transmitted by ticks•A liposome vaccine containing killed Babesia parasites induces protective immunity in mice•Immunity is mediated by CD4+ T cells and macrophages but is independent of B cells Babesiosis is an emerging parasitic infection of humans. It can cause flu-like illness in healthy people but severe disease and death in immunosuppressed individuals. Al-Nazal and colleagues describe a vaccine candidate, comprised of killed cultured parasites encased in a synthetic lipid membrane, that induces protective immunity against disease-causing Babesia species.
ISSN:	1931-3128 1934-6069