Location: Animal Disease Research
Project Number: 2090-32000-039-14-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Nov 18, 2016
End Date: Jan 31, 2020
The Animal Disease Research Unit (ADRU, ARS-USDA) in collaboration with the International Livestock Research Institute (ILRI) and other members of an international consortium, are developing a next generation vaccine against Theileria Parva (East Coast Fever, ECF). Characterizing the immune response in premunized livestock can aid development of the vaccine, and thus, there is interest in applying Atreca’s Immune Repertoire Capture™ (IRC™) technology to sequence the natively paired immunoglobulin genes expressed in single B cells from vaccinated livestock. IRC™ technology involves flow cytometry sorting of blasting B cells, bar-coding and PCR amplification of immunoglobulin cDNA from each single cell, next generation sequence analysis of pooled cDNA, and de-convolution of sequence data to link paired heavy and light chains expressed by single B cells.
The experimental plan is to use IRC™ to characterize the humoral immune response to Theileria parva p67 immunization. Sera from cattle in ECF endemic areas contain antibodies that in vitro neutralize parasite infectivity. As mentioned above, an abundant surface coat protein of T. parva sporozoites, called p67, is the primary target of such sera and neutralizing murine mAbs. This protein is highly conserved in sequence. Vaccination trials in cattle with recombinant p67 induced immunity to needle challenge in about 50% of the vaccinated cattle. In field trials the efficacy of this candidate vaccine antigen reduced to about 25%. Whole antigen ELISA and sporozoite neutralizing titers have not revealed any correlates with immunity to ECF, and there were no detectable differences in the IgG1 and IgG2 isotype response between immune and susceptible cattle.