Modulation of CD4+and CD8+T-Cell Function by Interleukin 19 and Interleukin 24 During Filarial Infections

Interleukin 19 (IL-19) and interleukin 24 (IL-24) are cytokines that are highly expressed in filarial infections. To study the role of IL-19 and IL-24 in regulating T-cell responses, we examined the frequency of T-helper type 1 (Th1)/Tc1, Th2/Tc2, Th9/Tc9, Th17/Tc17, Th22/Tc22, and Tr1 cells in 26 filariae-infected individuals stimulated with filarial antigen following IL-19 or IL-24 neutralization. IL-19 or IL-24 neutralization resulted in significantly enhanced frequencies of Th1/Tc1 and/or Th17/Tc17 cells and significantly reduced frequencies of Th2/Tc2, Tr1, and/or Th9/Tc9 cells. Thus, we demonstrate that IL-19 and IL-24 are associated with the modulation of T-cell responses in filarial infections

Parasite Antigen-Specific Regulation of Th1, Th2, and Th17 Responses in Strongyloides stercoralis Infection

Chronic helminth infections are known to be associated with modulation of antigen - specific CD4(+) T responses. However, the role of CD4(+) T cell responses in human infection with Strongyloides stercoralis (Ss) is not well-defined. To examine the role of CD4(+) T cells expressing Th1, Th2 and Th17 cytokines in strongyloidiasis, we compared the frequency of these subsets in infected individuals (INF) to frequencies (F(o)) in Ss-uninfected (UN) individuals. INF individuals exhibited a significant decrease in the spontaneous and antigen specific F(o) of both mono - and dual functional Th1 cells compared to UN. Similarly, INF individuals also exhibited significantly decreased F(o) of mono - and dual - functional Th17 cells upon antigen - stimulation compared to UN. In contrast, both the spontaneous and antigen - induced F(o) of mono- and dual - functional Th2 cells was significantly increased in INF compared to UN individuals. This differential T cell response was predominantly antigen - specific since it was abrogated upon control antigen or mitogen stimulation. The regulation of Th1, Th2 and Th17 cells was pre-dominantly dependent on IL-10, while the regulation of Th2 but not Th1 or Th17 cells was also dependent on TGFβ. In addition, treatment of Ss infection significantly increased the antigen - specific F(o) of Th1 and Th17 cells and decreased the F(o) of Th2 cells in INF individuals. Thus, Ss infection is characterized by a parasite - antigen dependent regulation of mono- and dual - functional Th1, Th2 and Th17 cells, a regulation also reversible by anti-helminthic treatment