Sheep were depleted of CD4+ (n = 7), CD8+ (n = 7), or WC1+ γδ (n = 7) T cells by intravenous administration of specific mAbs (GC1a, CC63, and CC15, respectively) over five consecutive days, initiated 2 days prior to infection with BTV (BTV-4 MOR2009/07) (Figure 1). Here, CD4 is linked to infection.