Production and characterization of anti-bifidobacteria monoclonal antibodies and their application in the development of an immuno-culture detection method

Flow cytometry: a versatile technology for specific quantification and viability assessment of micro-organisms in multistrain probiotic products

AIMS

Classical microbiology techniques are the gold standard for probiotic enumeration. However, these techniques are limited by parameters of time, specificity and incapacity to detect viable but nonculturable (VBNC) micro-organisms and nonviable cells. The aim of the study was to evaluate flow cytometry as a novel method for the specific quantification of viable and nonviable probiotics in multistrain products.

METHODS AND RESULTS

Custom polyclonal antibodies were produced against five probiotic strains from different species (Bifidobacterium bifidum R0071, Bifidobacterium longum ssp. infantis R0033, Bifidobacterium longum ssp. longum R0175, Lactobacillus helveticus R0052 and Lactobacillus rhamnosus R0011). Evaluation of specificity confirmed that all antibodies were specific at least at the subspecies level. A flow cytometry method combining specific antibodies and viability assessment with SYTO^® 24 and propidium iodide was applied to quantify these strains in three commercial products. Analyses were conducted on two flow cytometry instruments by two operators and compared with classical microbiology using selective media. Results indicated that flow cytometry provides higher cell counts than classical microbiology (P < 0·05) in 73% of cases highlighting the possible presence of VBNC. Equivalent performances (repeatability and reproducibility) were obtained for both methods.

CONCLUSIONS

This study showed that flow cytometry methods can be applied to probiotic enumeration and viability assessment. Combination with polyclonal antibodies can achieve sufficient specificity to differentiate closely related strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Flow cytometry provides absolute and specific quantification of viable and nonviable probiotic strains in a very short time (<2 h) compared with classical techniques (>48 h), bringing efficient tools for research and development and quality control.

Modulatory Effects of Chrysanyhemi Flos Pharmacopuncture on Nitric-oxide (NO) Production in Murin Macrophagy Cells

Objectives:

Much evidence exists that herbs have effective immunomodulatory activities. Chrysanthemi Flos (CF) is effective in clearing heat, reducing inflammation, dropping blood pressure and treating headache and is used as a pharmaceutical raw material for an immune enhancer. The purpose of this study was to investigate the modulatory effect of Chrysanthemi Flos pharmacopuncture on nitric-oxide (NO) production in activating macrophages.

Methods:

After a murine macrophage cell line, RAW 264.7, was cultured in the presence of lipopolysaccharide (LPS), immune-modulating abilities of CF were evaluated by using NO, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) production and phagocytic activity of macrophages.

Results:

CF enhanced the activities of macrophages by increasing the phagocytic activity and decreasing NO production. Especially, both LPS and CF, 200 ㎍/ml, treatment could significantly reduce the NO production, but did not change the production of IL-6 and TNF-α.

Conclusion:

The results of this study indicate that CF may be of immunomodulatory value, especially for adverse diseases due to increased NO production. It may have potential for use as immunoenhancing pharmacopuncture.

Oral administration of kefiran induces changes in the balance of immune cells in a murine model

The aim of the present study was to evaluate the effect of the oral administration of kefiran on the balance of immune cells in a murine model. Six week old BALB/c mice were treated with kefiran (300 mg/L) for 0, 2 and 7 days. Kefiran treatment increased the number of IgA+ cells in lamina propria after 2 and 7 days. Percentage of B220+/MHCII(high) cells in mesenteric lymph nodes (2 days) and Peyer's patches (7 days) was higher compared to untreated control mice. An increase of macrophages (F4/80+ cells) was observed in lamina propria and peritoneal cavity (2 and 7 days). In contrast, at day 7, macrophage population decreased in Peyer's patches. These results show the ability of kefiran to modify the balance of immune cells in intestinal mucosa. This property could be highly relevant for the comprehension of the probiotic effect attributed to kefir.