Diverse impact of a probiotic strain, Lacticaseibacillus paracasei Shirota, on peripheral mononuclear phagocytic cells in healthy Japanese office workers: a randomized, double-blind, controlled trial

Tomoaki Naito; Masatoshi Morikawa; Mayuko Yamamoto-Fujimura; Akira Iwata; Ayaka Maki; Noriko Kato-Nagaoka; Kosuke Oana; Junko Kiyoshima-Shibata; Yumi Matsuura; Rumi Kaji; Osamu Watanabe; Kan Shida; Satoshi Matsumoto; Tetsuji Hori

doi:10.12938/bmfh.2022-043

Diverse impact of a probiotic strain, Lacticaseibacillus paracasei Shirota, on peripheral mononuclear phagocytic cells in healthy Japanese office workers: a randomized, double-blind, controlled trial

Biosci Microbiota Food Health. 2023;42(1):65-72. doi: 10.12938/bmfh.2022-043. Epub 2022 Oct 11.

Affiliations

¹ Yakult Central Institute, 5-11 Izumi, Kunitachi, Tokyo 186-8650, Japan.
² Yakult Honsha Co., Ltd, 1-10-30 Kaigan, Minato, Tokyo 105-8660, Japan.

Abstract

Mononuclear phagocytic cells (MPCs) are classified into monocytes (Mos)/macrophages and dendritic cells (DCs) based on their functions. Cells of MPCs lineage act as immune modulators by affecting effector cells, such as NK cells, T cells, and B cells. This study aimed to investigate the effects of Lacticaseibacillus paracasei strain Shirota (LcS) ingestion on peripheral MPCs, particularly on their expression of functional cell-surface molecules enhanced in healthy adults. Thus, twelve healthy office workers consumed a fermented milk drink containing 1.0 × 10¹¹ cfu of LcS (LcS-FM) or a control unfermented milk drink (CM) once a day for 6 weeks. Peripheral blood mononuclear cells (PBMCs) were prepared from blood samples, and immune cells and functional cell-surface molecules were analyzed. We observed remarkable differences in the expression of HLAABC, MICA, CD40, and GPR43 in plasmacytoid DCs (pDCs) between the LcS-FM and CM groups, whereas no difference was found in CD86 or HLADR expression. The LcS-FM group exhibited higher CD40 expression in both conventional DCs (cDCs) and Mos, especially in type 2 conventional DCs (cDC2s) and classical monocytes (cMos); higher percentages of cMos, intermediate monocytes (iMos), and nonclassical monocytes; and higher numbers of cMos and iMos in PBMCs than the CM group. LcS ingestion increased the expression of HLAABC, MICA, CD40, and GPR43 in pDCs and CD40 in cDCs and Mos, particularly cDC2s and cMos. These results suggest that LcS modulates the function of MPCs that may lead to the regulation of immune effector functions in healthy adults.

Keywords: CD40; Lacticaseibacillus paracaseistrain Shirota (LcS); dendritic cell; monocyte.