Distinct roles of IL-27 produced by macrophages and dendritic cells in shaping the immune response against Plasmodium parasites

2021 Fiscal Year Research-status Report

• Project/Area Number: 20K16236
• Research Institution: Nagasaki University
• Principal Investigator: バヤルサイハン ガンチメグ 長崎大学, 医歯薬学総合研究科(医学系), 助教 (80841353)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: Interleukin 27 / malaria / macrophage / dendritic cells

Outline of Annual Research Achievements

To determine cell types that produce IL-27, we generated IL-27 reporter IL27p28-Venus mice and monitored its expression. We detected both dendritic cells (DCs) and macrophages express IL-27 during acute phase of the infection with P.chabaudi. DCs are the major antigen-presenting cells for the activation of adaptive immunity, and macrophages are critical effector cells to control parasitemia. Therefore, we speculated that IL-27 produced by these cells have differential roles in the regulation of immune responses during Plasmodium infection. To this end, we generated mice lacking IL-27 in DCs (IL27p28fl/flCD11c-Cre) or in macrophages (IL27p28fl/flLysM-Cre) and compared the response of these mice to the infection with P. chabaudi. Mice lacking IL-27 in DCs showed delay in the clearance of parasitemia than that in control mice (IL27p28fl/fl) during the acute phase of the infection, while those in macrophages exhibited earlier parasitemia peak and earlier clearance. Results suggested that the frequencies of activated CD4+ T cells (CD11ahiCD49dhi) and IFN-γ production in the spleen in response to malaria antigen were higher in mice lacking IL-27 in DCs than those in mice lacking IL-27 in macrophages. We also find malaria antigen specific antibody IgG1 and Ig2b were higher mice lacking IL-27 in DCs than those in mice lacking IL-27 in macrophages. These results suggest that IL-27 produced by DC and macrophages play qualitatively differential roles in the immune responses against Plasmodium infection.

Current Status of Research Progress

4: Progress in research has been delayed.

Reason

I was on maternity leave until September 2021. I am using two different conditional knockout mice, breeding of them takes longer than expected.

Strategy for Future Research Activity

Distinct roles of IL-27 produced by macrophages and dendritic cells in shaping the immune response against Plasmodium parasite
1.Kinetics of IL-27 produced by various immune cells during Pcc infection: Utilizing IL-27 reporter IL27p28-Venus mice, we will analyze kinetics of IL-27 produced by various immune cells in the spleen. According to preliminary data, not only DC and macrophages are the main producers of IL-27, but also NK cells produce similar level of IL-27 during the infection. We will confirm which cells produce IL-27 and compare the amount of IL-27 production by these cells.
2.Analysis of IL-27 production in mice lacking IL-27 in DCs (IL27p28fl/flCD11c-Cre) or in macrophages (IL27p28fl/flLysM-Cre): We will confirm which subsets of DC or macrophages (myeloid cells) lack IL-27 production in these conditional knockout mice during Pcc infection. Possible compensatory production of IL-27 in conditional knockout mice will be measured.
3.Localization of IL-27 producing cells in the spleen during Pcc infection: We will visualize cells by IHC and determine the cell type of l IL-27 producing cells interaction.
4.Germinal center response and secondary challenge response: Preliminary data suggested lower antigen specific response in mice lacking IL-27 in macrophages. We will compare germinal center response between mice lacking IL-27 in DCs (IL27p28fl/flCD11c-Cre) or in macrophages (IL27p28fl/flLysM-Cre) after infection with Pcc. Also we will check expansion of memory cells and antigen specific antibody response by rechallenge infection.

Causes of Carryover

I returned to work from maternity leave on September 2021. Research were not conducted until I return. I have leftover balance from fiscal year 2021. I need to purchase fluorescent antibodies, disposals and need to maintain conditional knockout mice for my experiments. Fluorescent-labeled antibodies will be used for flow cytometry and immunohistochemistry, these are the fundamental assays in my research. Purified mouse cytokines for ELISA will be purchased. Other reagents and chemicals required for immunological assays and cell cultures must be purchased. Disposable laboratory tools and plastic wares will be used often in daily research assays. Travel expenses are estimated for two domestic travels in each year for around 3-4 days accommodation in each trip. The purpose of the trip is attending and presenting my new data in the meeting of Japanese Society of Immunology (JSI) and Japanese Society of Parasitology (JSP). Overseas
travel expense is estimated for 4-5 days accommodation and round trip flights. The purpose of trip is to presenting new data and networking with
international scientists in the annual meeting International Congress of Immunology.