IL-22 dampens the T cell response in experimental malaria

Area of Science:

• Immunology
• Infectious Diseases
• Parasitology

Background:

• Plasmodial infections require strict regulation of pro- and anti-inflammatory immune responses to prevent severe pathology.
• Interleukin-22 (IL-22), a member of the IL-10 cytokine family, is crucial for immune regulation.
• Elevated IL-22 levels are observed in Plasmodium falciparum malaria and Plasmodium berghei ANKA (PbA) infected mice.

Purpose of the Study:

• To investigate the role of IL-22 in the immune response during PbA infection.
• To understand the impact of IL-22 deficiency on malaria pathology and immune cell function.

Main Methods:

• Analysis of plasma IL-22 levels in malaria-infected patients and mice.
• Phenotyping of immune responses in IL-22 deficient (Il22(-/-)) and wild-type (wt) mice infected with PbA.
• In vitro co-culture experiments assessing dendritic cell and T cell interactions.

Main Results:

• IL-22 deficiency in mice led to earlier cerebral malaria onset but lower parasitemia.
• PbA-infected Il22(-/-) mice exhibited increased IFNγ and decreased IL-17 production by T cells.
• Dendritic cells from Il22(-/-) mice showed higher CD86 expression and enhanced induction of antigen-specific IFNγ responses by CD8(+) T cells.

Conclusions:

• IL-22 influences the severity of experimental cerebral malaria.
• IL-22 deficiency alters T cell responses (IFNγ, IL-17) and dendritic cell function during PbA infection.
• A link exists between IL-22 and the adaptive immune system, despite the absence of a known IL-22 receptor on hematopoietic cells.