The purpose of this study was to investigate probiotic characteristics and immune enhancing effects of Bifidobacterium (B.) longum KBB1-26 and BIF-4, B. breve KBB5-22 isolated from human intestine for probiotic use in humans and animals. We measured acid, bile and heat tolerance, antimicrobial activity against pathogenic bacteria, Escherichia (E.) coli, Salmonella (S.) Enteritidis, Staphylococcus (S.) aureus, and Listeria (L.) monocytogenes. Immune enhancing effects of B. longum and B. breve were investigated by measuring nitric oxide (NO), nuclear factor (NF–κb), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-12 (IL-12) and tumor necrosis factor- α (TNF- α) in RAW 264.7 cells or RAW BLUE cells. B. longum KBB1-26 was survived at pH 2.0. B. longum KBB1-26 and BIF-4, B. breve KBB5-22 also showed tolerance to 0.3% of oxgall bile salt. B. longum KBB1-26 was able to survive at 70 ℃ and 80 ℃ for 20 min. KBB1-26 showed the antimicrobial inhibition zone to pathogenic bacteria such as E. coli (12 mm), S. Enteritidis (14 mm), S. aureus (14 mm) and L. monocytogenes (41 mm). The production of NO (4.5 ± 0.00μM/mL) and IL-1β (39.7 ± 0.55pg/mL) of KBB1-26 significantly higher than BIF-4 and KBB5-22, respectively. In addition, KBB1-26 and KBB5-22 induce the production of high level of TNF-α and IL-6 in macrophages. Collectively, B. longum KBB1-26 have acid, bile, heat tolerance, antimicrobial activity and immune enhancing effects. These results suggest that KBB1-26 can be used as probiotics for humans and animals.

Aging is a growing concern of age-associated aberrations in immune system or immunosenescence. Probiotics contain not only these general health advantages but also other the regulation of host immune function. Among those probiotics, the immunomodulatory effects of Weissella cibaria JW15 (JW15) strain has already been reported in our previous studies. The objective of this study is to assess improved immunity of JW15 strain in aged mice. In experiment, mice were divided into five groups. Twenty eight–month-old C57BL/6J mice were given a daily dose of 1×109 CFU/ mouse (JW15-H group) and 1×108 CFU/mouse (JW15- L group) of viable JW15. The young mice group (YM) and old mice group (OM) were given PBS. After four weeks of administration, mice were euthanized. Mice blood was collected and analyzed for complete blood cell count (CBC). Then, mice spleen was weighed and analyzed for splenocyte. Finally, we measured the concentration of cytokine secreted by splenocyte and serum. The results showed splenocyte proliferation of JW15-L group by the addition of LPS and concanavalin A was significantly higher than that of OM group. Splenocyte TNF-α production was significantly increased by JW15 intake. In particular, splenocyte TNF-α production of JW15-L group by the addition of LPS (5 μg/mL) was significantly greater than that other group. Splenocyte IL-6 production was also the highest in JW15-L group. Serum IFN-γ production of JW15-L (59.13 ± 16.13 pg/mL) group was significantly higher than that of OM group (39.71 ± 2.51 pg/ mL). When compared to the OM group (32.22 ± 1.92 pg/mL), Serum TNF-α production was significantly increased by JW15-H intake (69.01± 26.51 pg/mL). In conclusion, JW15 enhanced immunomodulative effects. In particular, the effect was significantly excellent in JW15-L group (1 × 108 CFU/mouse). Therefore, Weissella cibaria JW15 would be suitable for consideration as a helpful functional food for companion animals and humans.

Lactic acid bacteria (LAB) are known to promote activation of macrophages, selectively eliminate harmful intestinal bacteria that enter the body, and increase secretion of cytokines, chemokines, and inflammatory mediators that boost the immune system. In the current study, the immune-enhancing effects of five Leuconostoc stains (Leu. kimchii WK18, Leu. citreum DH33, Leu. mesenteroides DH34, SE34, and GY17) isolated from traditional Korean fermented food, Kimchi, were evaluated. Lactobacillus rhamnosus GG (LGG), which is known for its extraordinary immunopotentiating activity, was used as a reference strain. According to the results, several heat-killed Leuconostoc strains induced a higher level of NO, IL-1β, or TNF-α production than the LGG strain. Collectively, results of the current study suggest that Leuconostoc strains could enhance immune response through activation of macrophages, and could be significant references when verifying the possibility for use of Leuconostoc strains as probiotics, starter, dietary supplement, or immune-enhancing medicine.

Recently, as a natural substance has been emphasized interest in research to enhance the immune function. Green lettuce (Lactuca sativa L.) is a popular vegetable used fresh and it contains various phytochemicals and antioxidant compounds, and has been reported to have various physiological activities such as antibacterial, antioxidant, antitumor and anti-mutagenic. However, only a few studies have investigated on the mechanism of action of immune-enhancing activity of lettuce. Therefore, in this study, the immunomodulatory activities and potential mechanism of action of Green lettuce extracts (GLE) were evaluated in the murine macrophage cell line RAW264.7. GLE significantly increased NO levels by RAW264.7 cells, as well as expressions of immunomodulators such as iNOS, COX-2, IL-1β, IL-6, IL-12, TNF-α and MCP-1. Although GLE activated ERK1/2, p38, JNK and NF-κB, GLE-mediated expressions of immunomodulators was dependent on p38, JNK and NF-κB. In addition, TLR4 inhibition blocked GLE-mediated expressions of immunomodulators and activation of p38, JNK and NF-κB. Taken together, these results demonstrated that TLR4-MAPK/NF-κB signalling pathways participated in GLE-induced macrophage activation and GLE could be developed as a potential immunomodulating functional food.

This study investigated the immune-enhancing effects of polysaccharides extracted from Gloiopeltis furcata (red seaweed) with different molecular weights. A crude polysaccharide mixture was hydrolyzed using acid treatment (0.1 N HCl) and three molecular weight fractions were generated and filtered using centrifugation: (≤10 kDa, 10 to 100 kDa, and 100 kDa. Nitric oxide (NO) production in RAW264.7 cells treated with 0.01-0.5 μg/mL polysaccharides ≥100 kDa was 12.28-19.05 μM. Treatment with polysaccharides ≥100 kDa increased cytokine levels, including TNF-α and IL-6 levels, in a dose-dependent manner. Polymerase chain reaction analysis also revealed marked increases in iNOS and COX-2 mRNA expression levels. These findings lead us to conclude that macrophage activation induced by polysaccharides ≥100 kDa was greater than that induced by polysaccharides ≤10 kDa or between 10 and 100 kDa. The polysaccharides ≥100 kDa extracted from Gloiopeltis furcata investigated herein are potentially useful as natural immune-enhancing agents. These findings provided further insights into the potential use of ≥100 kDa as immunopotentiator or new function food.