Investigation of Immunostimulatory Effects of Heat-treated Lactiplantibacillus plantarum LM1004 and its Underlying Molecular Mechanisms

Won-Young Bae1,*, Woo-Hyun Jung1, So Lim Shin1, Seulgi Kwon1, Minn Sohn1, Tae-Rahk Kim1
Author Information & Copyright
1Microbiome R&D Center, Lactomason, Seoul 06620, Korea.
*Corresponding Author: Won-Young Bae, Microbiome R&D Center, Lactomason, Seoul 06620, Korea. Phone: +82-2-2677-0073. E-mail:

© Copyright 2022 Korean Society for Food Science of Animal Resources. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Jun 09, 2022 ; Revised: Jul 29, 2022 ; Accepted: Aug 24, 2022

Published Online: Sep 06, 2022


Postbiotics are defined as probiotics inactivated by heat, ultraviolet radiation, sonication, and other physical or chemical stresses. Postbiotics are more stable than probiotics, and these properties are advantageous for food additives and pharmacological agents. This study investigated the immunostimulatory effects of heat-treated Lactiplantibacillus plantarum LM1004 (HT-LM1004). Cellular fatty acid composition of L. plantarum LM1004 isolated form kimchi was analyzed by GC/MSD system. The nitric oxide (NO) content was estimated using Griess reagent. Immunostimulatory cytokines were evaluated using enzyme-linked immunosorbent assay (ELISA). Relative protein expressions were evaluated by western blotting. Phagocytosis was measured using enzyme-labelled Escherichia coli particles. L. plantarum LM1004 showed 7 kinds of cellular fatty acids including palmitic acid (C16:0). The HT-LM1004 induced release of NO and upregulated the inducible nitric oxide synthase in RAW 264.7 macrophage cells. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were also increased compared to control (non-treated macrophages). Furthermore, HT-LM1004 modulated mitogen-activated protein kinase (MAPK) subfamilies including p38 MAPK, ERK1/2, and JNK. Therefore, these immunostimulatory effects were attributed to the production of transcriptional factors, such as nuclear factor kappa B (NF-κB) and the activator protein 1 family (AP-1). However, HT-LM1004 did not showed significant phagocytosis of RAW 264.7 macrophage cells. Overall, HT-LM1004 stimulated MAPK/AP-1 and NF-κB expression, resulting in the release of NO and cytokines. These results will contribute to the development of diverse types of food and pharmacological products for immunostimulatory agents with postbiotics.

Keywords: Lactobacillus plantarum; postbiotics; immunostimulatory effect; nuclear factor kappa B