Atre T, Robinson TM, Savransky T, Dutta S, Epstein JE, Bergmann-Leitner ES. Novel sporozoite-based ELISpot assay to assess frequency of parasite-specific B cells after vaccination with irradiated sporozoites.
Malar J 2019;
18:186. [PMID:
31142328 PMCID:
PMC6540377 DOI:
10.1186/s12936-019-2819-6]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 05/18/2019] [Indexed: 11/29/2022] Open
Abstract
Background
Whole parasite vaccination is an efficacious strategy to induce sterile immunity and to prevent malaria transmission. Understanding the mechanism and response of immune cells to vaccines plays a critical role in deciphering correlates of protection against infection and disease. Immunoassays, such as ELISpot, are commonly used to assess the immunogenicity of vaccines towards T cells and B cells. To date, these assays only analyse responses to specific antigens since they are based on recombinant parasite-derived proteins or peptides. There is the need for an agnostic approach that allows the evaluation of all sporozoite-associated antigens.
Methods
ELISpot plates coated with a defined amount of lysed Plasmodium falciparum sporozoites were used to assess the frequency of sporozoite-specific B cells in peripheral blood mononuclear cells from donors immunized with either a recombinant malaria vaccine or irradiated sporozoites.
Results
This report describes the assay conditions for a specific and sensitive sporozoite-based B cell ELISpot assay. The assay development considers the quality of sporozoite preparation as well as the detection threshold of the frequency of antigen-specific B cells. The assay enables the detection of sporozoite-specific IgM and IgG-producing B cells. Moreover, the assay can detect sporozoite-reactive B cells from subjects that were either vaccinated with the radiation attenuated sporozoite vaccine or a recombinant pre-erythrocytic vaccine.
Conclusion
The newly developed sporozoite-based B cell ELISpot enables the monitoring of changes in the frequency of sporozoite-specific B cells. Applying this assay to assess the potency of vaccination regimens or seasonal changes in B cell populations from subjects residing in malaria-endemic areas will provide an opportunity to gain insight into immune mechanisms involved in protection and/or disease.
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