HIF1A and infection: On the other hand, the constitutive activation of HIF-1α in VHL-null mice have in turn increased intracellular killing of GAS and P. aeruginosa. To assess the role of HIF-1α in regulating myeloid cell bactericidal function in vivo, the group then adopted an infection model of GAS and found that mice with HIF-1α genetic deficiency in myeloid cells developed greater necrotic skin lesions.