** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** OUR RESEARCH PROJECT FOCUSES ON A DISEASE IN CATTLE CALLED BOVINE VIRAL DIARRHEA VIRUS (BVDV),WHICH ISA BIG PROBLEM FOR FARMERS BECAUSE IT AFFECTS THE HEALTH AND IMMUNE SYSTEM OF YOUNG COWS, KNOWN AS CALVES. THIS VIRUS COMES IN TWO FORMS: ONE THAT CAUSES PERSISTENT INFECTIONS CALLED NON-CYTOPATHIC (NCP) AND ANOTHER CALLED CYTOPATHIC (CP), WHICH CANNOT CAUSE PERSISTENT INFECTIONS AND IS THEREFORE USED IN VACCINES TO PREVENT THE DISEASE. HOWEVER, BOTH TYPES OF THE VIRUS CAN DAMAGEAN IMPORTANTORGAN IN THE CALVES CALLED THE THYMUS.THE THYMUS IS CRUCIAL BECAUSE IT HELPS DEVELOP SPECIALCELLS CALLED T-CELLS, WHICH AREAKEYPART OF THE IMMUNE SYSTEM THAT FIGHTS OFF INFECTIONS.WHEN THE THYMUS IS DAMAGED, IT DOESN'T WORKPROPERLY, AND ASA RESULT, THE CALVES MAY NOT RESPOND WELL TO INFECTIONS OR EVEN VACCINES. OUR PRELIMINARY STUDIES HAVE SHOWN THAT AFTER BEING INFECTED WITH BVDV, THE THYMUS MIGHT BECOME SMALLER ANDPERMANENTLY DAMAGED, AFFECTING THE CALF'S ABILITY TO FIGHT OTHER DISEASES.THIS DAMAGE IS SEEN IN HOWCERTAINIMMUNE CELLS, CALLED CD8 CELLS, DON'TRESPONDAS WELL AS THEY SHOULD. ANOTHER PROBLEM IS WITH SOMETHING CALLED THE T-CELL RECEPTOR (TCR) DIVERSITY. TCRS ARE ON THE SURFACE OF T-CELLS AND HELP THEM RECOGNIZE AND FIGHT DIFFERENT INFECTIONS. IF THERE ISN'T ENOUGH DIVERSITY IN THESE RECEPTORS, THE CALVES MIGHTNOT BE ABLETO FIGHT OFFINFECTIONSEFFECTIVELY. THE GOAL OF OUR PROJECT ISTO STUDY THESE EFFECTS IN MORE DETAIL TO UNDERSTAND HOW BVDV AFFECTS THE THYMUS AND T-CELL RECEPTORS SO WE CANBETTERPROTECT CALVES FROM THIS VIRUS AND IMPROVE VACCINES.THIS RESEARCH COULD LEAD TO BETTER HEALTH MANAGEMENT IN CATTLE AND ENSURE THAT VACCINES ARE EFFECTIVE, HELPING FARMERS MAINTAIN HEALTHY ANIMALS.