# Immunological characterization of the P. vivax DBP

> **NIH NIH R01** · UNIVERSITY OF SOUTH FLORIDA · 2020 · $641,106

## Abstract

Project Summary/Abstract
Plasmodium vivax Duffy binding protein ligand domain (DBPII) is a leading vivax vaccine candidate based
upon its relative importance for parasite survival during the disease-causing blood stage. However, DBPII is
naturally weakly immunogenic and induces strain-specific immunity. Our approach to solve the problem
strain immunity is to design a vaccine that focuses antibody responses onto conserved B-cell epitopes in
functional regions within DBPII that are proven targets of protective immunity. In a proof-of-concept study,
we demonstrated that an engineered DBPII immunogen lacking the dominant variant B-cell epitope retained
good immunogenicity and induced more broadly inhibitory antibodies (BIAbs). The results for the DBPII-
engineered vaccine is promising and the next critical step will be to determine the requirements to induce
long-lived antibody and memory B-cell (MBCs) responses targeting conserved neutralizing epitopes. The
overall goal of this program is to design a vaccination strategy to induce the distinct subpopulations of B-
cells that are expanded in people with protective immunity to vivax malaria. Our hypothesis is people able to
produce broadly naturally acquired DBPII BIAbs (elite responders) mount an efficient and long-term DBPII-
specific memory B-cells (MBCs) and this can be replicated by vaccination. We will phenotypically and
functionally characterize B cell sub-sets in immune individuals, to optimize the design of new DBPII vaccine
that can induce MBCs cells with specificity for different DBPII. For that, we will take advantage of Brazilian
cross-sectional and cohort studies, where different profiles of DBPII responders were identified, including
persistent responders with strain-transcending DBPII-BIABs. DBPII is expected to be an important
component of a multi-stage, multi-valent vaccine to protect against vivax malaria. The proposal builds on a
solid and successful collaboration established between the Brazilian and US collaborators, combining
strengths parasitology, immunology, and structural biology to optimize DBPII as an effective vaccine against
vivax malaria.

## Key facts

- **NIH application ID:** 9920658
- **Project number:** 5R01AI064478-13
- **Recipient organization:** UNIVERSITY OF SOUTH FLORIDA
- **Principal Investigator:** John H Adams
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $641,106
- **Award type:** 5
- **Project period:** 2006-08-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9920658

## Citation

> US National Institutes of Health, RePORTER application 9920658, Immunological characterization of the P. vivax DBP (5R01AI064478-13). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9920658. Licensed CC0.

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