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Human whipworm (Trichuris trichiura) infects approximately 1 in 15 people worldwide, representing the leading infectious cause of colitis and subsequent, inflammatory bowel disease (IBD). Current control measures focused on mass deworming have had limited success due to low drug efficacies. Vaccination would be an ideal, cost-effective strategy to induce protective immunity, leading to control of infection and transmission. Here we report the identification of whey acidic protein, a whipworm secretory protein, as a strong immunogen for inducing protective efficacy in a surrogate mouse T. muris infection model. The recombinant WAP protein (rTm-WAP49), as well as a single, highly conserved repeat within WAP (fragment 8) expressed as an Na-GST-1 fusion protein (rTm-WAP-F8+Na-GST-1), generate a strong T helper type 2 (Th2) immune response when delivered as subcutaneous vaccines formulated with Montanide ISA 720. Oral challenge with T. muris infective eggs following vaccination led to a significant reduction in worm burden of 48% by rTm-WAP49 and 33% by rTm-WAP-F8+Na-GST-1. The cellular immune correlates of protection included significant antigen-specific production of Th2 cytokines IL-4, IL-9, and IL-13 by cells isolated from the vaccine-draining inguinal lymph nodes, parasite-draining mesenteric lymph nodes, and spleen in mice vaccinated with either rTm-WAP49 or rTm-WAP-F8+Na-GST-1. The humoral immune correlates included a high antigen-specific ratio of IgG1 to IgG2a, without eliciting an IgE-mediated allergic response. Immunofluorescent staining of adult T. muris with WAP antisera identified the worm's pathogenic stichosome organ as the site of secretion of native Tm-WAP protein into the colonic mucosa. Given the high sequence conservation for the WAP proteins from T. muris and T. trichiura, the results presented here support the WAP protein to be further evaluated as a potential human whipworm vaccine candidate.

OBJECTIVES/SPECIFIC AIMS: Trichuris trichiura, is a leading cause of chronic colitis worldwide, resulting in growth stunting, anemia, and cognitive deficits, predominately in children. Our long-term goal is to develop a vaccine against T. trichiura. Both T. trichiura and the closely related Trichuris muris release excretory/secretory (ES) macromolecules from the stichosome organ, which facilitates intracellular invasion into the cecum. We exploited the high degree of genetic sequence homology between T. trichiura and T. muris to evaluate T. muris stichosome proteins as vaccine candidates. METHODS/STUDY POPULATION: Through immunological screening of the T. muris stichosome cDNA library and T. muris ES macromolecules generated in culture, we identified, cloned, and expressed several vaccine candidates. In ranking these antigens, we selected the most promising recombinant proteins, WAP and CAP-1, and vaccinated AKR mice to evaluate the immunogenicity and efficacy of our candidate. In addition, we collected 240 serum samples in the T. trichiura endemic region of Honduras to measure the recognition of WAP and CAP-1 in naturally infected human. RESULTS/ANTICIPATED RESULTS: We measured a statistically significant reduction in larval worm burden in WAP and ES vaccinated mice, but not CAP-1, by microscopy and real-time PCR of T. muris DNA. We found a significant relationship between antigen-specific IgG1:IgG2a ratio in the mouse serum and degree of protection. Mouse splenocytes, vaccine-sensitized draining lymph nodes, and mesenteric lymph nodes were antigen-stimulated and their secreted Th1, Th2, and Th17 cytokines were measured by Luminex®. Stimulated mouse lymphoid cells were further analysed for T helper, T cytotoxic, and central/effector memory T cells by Flow Cytometry. Human IgG1, IgG2, and IgE antibody titers against WAP and CAP-1 were measured by ELISA. DISCUSSION/SIGNIFICANCE OF IMPACT: In our study, we describe the T cell dependent mechanism of humoral immunity of 2 promising ES-derived vaccines recombinant proteins, WAP and CAP-1. We evaluated the immune response, indicating a driving a Th2-induced humoral response necessary for protection. We further predict protection and allergenicity of WAP in humans using serum from a cohort in an T. trichiura endemic region.