Analysis of Invariant Natural Killer T Cells in Human Paracoccidioidomycosis

Abstract

Invariant natural killer T (iNKT) cells are capable of recognizing lipid antigens and secreting Th1/Th2 cytokines. Deficiency in iNKT cell number or function has been partially implicated in susceptibility to some infectious diseases, such as tuberculosis. We evaluated iNKT cells in paracoccidioidomycosis, another chronic granulomatous disease endemic in Latin America. iNKT cells were detected using PBS57-loaded tetramer staining and flow cytometry. Circulating iNKT cell numbers were similar among healthy individuals who had previously been cured of paracoccidioidomycosis (susceptible individuals, n = 7) and healthy Paracoccidioides brasiliensis-infected (n = 5) and non-infected individuals (n = 5). iNKT from all three groups expanded similarly upon alpha-GalCer and a synthetic analog (OCH) stimulation. IFN-gamma was the dominant cytokine produced both by ex vivo and by expanded iNKT cells, followed by IL-4 and IL-10, in the three groups. No deficit in the monocyte expression of CD1d was detected. In conclusion, individuals who had developed paracoccidioidomycosis in the past have no impairment in iNKT number, expansion capacity, and cytokine secretion.