1a.Objectives (from AD-416):
This Trust Fund Cooperative Agreement is to develop new strategies to induce cross protective immunity to avian coccidiosis using multivalent recombinant coccidiosis vaccine and to investigate immune markers associated with protective immunity.
1b.Approach (from AD-416):
ARS identified several potential vaccine antigens of Eimeria that will be used in vaccination trials at ARS. Two recombinant antigens will be mixed in adjuvants which will be provided by the CAVAC and will be used to immunize broiler chickens at ARS. Challenge will be carried out using E. tenella, E. acervulina, and E. Maxima species and clinical parameters (oocysts, body weight, gut lesions) and various host immune responses (antibody response, T-cell proliferation response, cytokines) will be evaluated.
During this reporting period, oocyst purification and sporocyst freezing methods were developed and improvement in infectivity of oocysts were demonstrated by live bird trials. To improve sporocyst production, sporulation of oocysts were carried out immediately after collection of oocysts from Eimeria-infected intestine tissues at room temperature. Optimum freezing method for sporocysts was developed by using a mini-beadbeater cell disrupter, and cell freezing medium which consisted of fetal calf serum supplemented with 10% DMSO. Good viability was obtained after thawing. We will now study the effect of temperature on viability.