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Defining conserved epitopes on polymorphic malaria antigens

Award Number: R01AI153425
ORGANIZATION: NATIONAL INSTITUTE OF ALLERGY & INFECTIOUS DISEASES
OPDIV: NIH
AWARD CLASS: DISCRETIONARY
AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)
PERIOD OF PERFORMANCE START DATE: 02/19/2021
PERIOD OF PERFORMANCE END DATE: 01/31/2026

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Defining conserved epitopes on polymorphic malaria antigens - PROJECT SUMMARY Malaria is still responsible for an estimated 429,000 deaths and 212 million infections per year, the large majority among young children. Individuals living in endemic regions gradually develop an immune response that protects against symptomatic disease. Naturally acquired immunity targets the blood stage of the parasite’s life cycle and is largely dependent on antibody reactivity. Elicitation of a similar immune response by vaccination in young, non-immune children would dramatically reduce malaria morbidity and mortality. Various parasite antigens have been associated with protection against clinical disease. Most of these antigens are expressed in the merozoite stage and are involved in invasion of the red blood cell. However, vaccine trials based on these blood-stage antigens have thus far been unsuccessful. One factor contributing to the failure of blood stage vaccines is the extensive genetic diversity between different parasite strains that has resulted in strain-specific, but not strain- transcending, antibody responses. Studies of naturally acquired immunity suggest that protected individuals harbor antibodies against conserved epitopes. The identification of such conserved epitopes could serve as a blueprint for structure-based design of a malaria blood stage vaccine. We hypothesize that immunity against malaria is dependent on high affinity IgGs with cross-strain reactivity against merozoite antigens and that these antibodies can be used to define conserved epitopes on merozoite vaccine candidates. To test this hypothesis, we will compare the molecular and functional characteristics of antibodies directed against merozoite antigens among immune adults, semi-immune children and non-immune children living in Tororo, Uganda, a region with extremely high malaria transmission intensity, and use the most potent and broadly reactive antibodies for epitope mapping. In Specific Aim 1, we will isolate merozoite antigen-specific memory B cells from these individuals, test the ability of these antibodies to inhibit various malaria parasite strains in vitro, and map the epitopes of cross-strain reactive antibodies to define conserved epitopes on merozoite antigens. In Specific Aim 2, we will deep-sequence the memory B cell receptor repertoire to uncover the impact of life-long malaria exposure on the humoral immune response, analyze the repertoire of anti-merozoite serum antibodies and determine the cross-strain inhibitory activity and epitopes of dominant serum antibody clonotypes. Collectively, the results from these experiments will provide detailed information about the types of antibodies that a blood-stage vaccine should ideally elicit and will enable the design of novel immunogens to elicit strain- transcending antibodies against the malaria blood stage. In addition, it will provide insight into the overlap and differences between the memory B cell and serological compartments, and the selective mechanisms that drive B cell differentiation into plasma cells and memory B cells.


Issue Date FY	Funding FY	Legal Entity Name	Legal Entity Address	Legal Entity City	Legal Entity State	Legal Entity Zip Code	Legal Entity COUNTY	Legal Entity COUNTRY	Assistance Listing	Award Code	Budget Year	Action Date	Action Type	Action Amount

Issue Date FY: 2025 ( Subtotal = $527,357 )
2025	2025	THE UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER AT SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	000	5	1/23/2025	NON-COMPETING CONTINUATION	$527,357
														Subtotal = $527,357

Issue Date FY: 2024 ( Subtotal = $554,417 )
2024	2024	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	000	4	1/12/2024	NON-COMPETING CONTINUATION	$489,300
2024	2024	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	001	4	1/23/2024	SUPPLEMENT FOR EXPANSION	$10,750
2024	2024	THE UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER AT SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	002	4	5/31/2024	NON-COMPETING CONTINUATION	$54,367
														Subtotal = $554,417

Issue Date FY: 2023 ( Subtotal = $609,717 )
2023	2023	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	001	3	2/3/2023	SUPPLEMENT FOR EXPANSION	$66,050
2023	2023	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	000	3	1/11/2023	NON-COMPETING CONTINUATION	$543,667
														Subtotal = $609,717

Issue Date FY: 2022 ( Subtotal = $601,167 )
2022	2022	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	001	2	5/9/2022	SUPPLEMENT FOR EXPANSION	$55,300
2022	2022	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	000	2	1/27/2022	NON-COMPETING CONTINUATION	$545,867
														Subtotal = $601,167

Issue Date FY: 2021 ( Subtotal = $434,155 )
2021	2021	UNIVERSITY OF TEXAS HEALTH SCIENCE CENTER OF SAN ANTONIO	7703 FLOYD CURL DR	SAN ANTONIO	TX	78229	BEXAR	USA	Allergy and Infectious Diseases Research	000	1	2/19/2021	NEW	$434,155
														Subtotal = $434,155

Grand Total All Awards = $2,726,813

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Defining conserved epitopes on polymorphic malaria antigens

Award Number: R01AI153425

ORGANIZATION: NATIONAL INSTITUTE OF ALLERGY & INFECTIOUS DISEASES

OPDIV: NIH

AWARD CLASS: DISCRETIONARY

AWARD ACTIVITY TYPE: SCIENTIFIC/HEALTH RESEARCH (INCLUDES SURVEYS)

PERIOD OF PERFORMANCE START DATE: 02/19/2021

PERIOD OF PERFORMANCE END DATE: 01/31/2026

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