PDHX and infection: More detailed kinetic analysis of the expression levels of all PDK isoforms (PDK1-4) and other components of the PDC (PDP1, PDP2, PDHX, PDHA1 and PDHB) showed that several PDK isoforms and catalytic subunits of the PDC were significantly regulated upon infection with Stm, in contrast to infection with Mtb (Figure 3B), suggesting that pyruvate metabolism was modulated in human macrophages during Stm infection.