CCL22 and bacterial infectious disease: Interestingly, Safronova et al. (29) showed that human PBMCs infected with T. gondii secrete large amounts of CCL-2, CCL-22, and IL-8 but not IL-12, remarking the differences between species, as it has also been reported for the response to bacterial infections, challenging the usual view about the role of IL-12 in the human immune response (29, 31).