Following infection of CID-9 cells with Ad-DN-STAT5, prolactin stimulation still resulted in phosphorylation of STAT5 at tyrosine residue 694 at 24 and 48 hours; however, due to the deletion of the transactivation domain, prolactin induced PAD3 expression was blunted at 48 hours (Fig 4B). Here, STAT5A is linked to infection.