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United States Department of Agriculture

Agricultural Research Service

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Location: Animal Parasitic Diseases Laboratory

2013 Annual Report

1a. Objectives (from AD-416):
To evaluate vaccine adjuvants using Neospora caninum antigens in the mouse model of neosporosis. Due to the recent restructuring of the research project plan objectives, the original Objectives for this agreement have been updated to reflect the following: 1) Neospora caninum antigens will NOT be used in this research, and 2) nematode parasite antigens will be used for the evaluation of adjuvants produced by the cooperator in the mouse and small ruminant models.

1b. Approach (from AD-416):
Neospora caninum antigens will be formulated with Pfizer adjuvants and used to immunize the mouse model (BALB/C) of neosporosis. Humoral (antibody response) and cell-mediated immunities (T cell and cytokine response) of the immunized mice will be determined in vitro. Due to recent changes in the research project objectives, the original Approach of this Trust Agreement has been updated to reflect the following: 1) Neospora caninum antigens will NOT be used in this research, and 2) nematode parasite antigens will be formulated in adjuvants (5-10 adjuvants favoring Th2 responses) produced by Pfizer, Inc., mice and small ruminants will be immunized and immune responses to nematode antigens will be characterized.

3. Progress Report:
The primary focus of this agreement was to evaluate and compare Pfizer's proprietary vaccine adjuvants in combination with candidate subunit vaccines against livestock parasites. Properly designed adjuvants are indispensable for enhanced immunogenicity and protective efficacy of the subunit vaccines. Thus, this collaboration with a leading industry company in adjuvant development benefited ARS research on subunit vaccine development. A total of 5 Pfizer-formulated adjuvants (coded as QCDCRT, TXO, TCMO, QCDCRTc, and ISCX) were investigated in mice and sheep. Results in mice showed that the effects of the adjuvants TXO and TCMO were far more superior to those of the other adjuvants tested. TXO and TCMO significantly enhanced parasite antigen-specific T cell proliferation and cytokine production in mice. Parasite-specific antibody production was enhanced in both mice and sheep. Overall, TXO favored a type 1 immune response characterized by high interferon-gamma (IFNg) and low interleukin-4 (IL-4) production, whereas TCMO promoted a mixed type 1 and type 2 T cell response. Both TXO and TCMO should be excellent adjuvants for vaccines against intracellular pathogens such as Neospora caninum. However, TCMO could also be used for some pathogens that require balanced type 1 and type 2 responses. This research has mutually benefited the industry and ARS research by clearly identifying effective adjuvants that could be used for developing vaccines against a variety of livestock diseases including parasitic diseases. This research will produce one peer-reviewed publication.

4. Accomplishments

Last Modified: 06/23/2017
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