IL-27 produced during acute malaria infection regulates Plasmodium-specific memory CD4⁺ T cells

Area of Science:

• Immunology
• Infectious Diseases
• T cell biology

Background:

• Malaria infection triggers complex immune responses, with Interleukin-27 (IL-27) playing a key role in regulating T cell effector functions.
• CD4+ T cells are critical for adaptive immunity against malaria, but their differentiation and memory formation are tightly regulated.

Purpose of the Study:

• To investigate the role of IL-27 in shaping CD4+ T cell responses during acute and chronic malaria infection.
• To identify the impact of IL-27 neutralization on the development and maintenance of Plasmodium-specific CD4+ T cells.

Main Methods:

• Utilized Plasmodium chabaudi infection model in mice.
• Administered IL-27 neutralizing antibodies during the acute phase of infection.
• Analyzed CD4+ T cell populations using flow cytometry and single-cell RNA sequencing (scRNA-seq).
• Assessed cellular and humoral immune responses and protection.

Main Results:

• Neutralization of IL-27 during acute malaria led to an expansion and sustained high levels of specific CD4+ T cells.
• IL-27-neutralized mice developed distinct CD4+ T cell subpopulations (CD127+ KLRG1- and CD127- KLRG1+) with unique functional properties.
• scRNA-seq revealed these subsets formed independent clusters expressing Th1-type genes.
• IL-27 neutralization resulted in enhanced cellular and humoral immunity and improved protection against malaria.

Conclusions:

• IL-27, produced during acute malaria, inhibits the development of unique Th1 memory precursor CD4+ T cells.
• Targeting IL-27 may offer a strategy to enhance protective immunity and T cell memory in malaria.
• Findings suggest implications for vaccine development and therapeutic interventions against malaria.