[23] in in vivo study identified DEFB1, BNBD4, BNBD5, LAP and TAP transcripts in different parts of the mammary gland, including the alveoli, as a result of intramammary infection with S. aureus. Although the expressions of BNBD4 and BNBD5 were strongly induced, the expression of DEFB1 was only moderately induced, while the expressions of LAP and TAP were not induced in mammary alveoli by the presence of bacteria. Here, DEFB1 is linked to infection.