1.In vitro evaluation of cell adhesion and immunomodulatory properties of five Lactobacillus rhamnosus strains isolated from infants
Hlaing Hlaing Thaw ; Namfon Seubwongsa ; Rattiya Thongrung ; Marutpong Panya ; Viraphong Lulitanond
Malaysian Journal of Microbiology 2017;13(4):343-349
Aims: Five Lactobacillus rhamnosus strains (UBU03, UBU06, UBU09, UBU34 and UBU37) with good in vitro probiotic
properties, isolated from breast-fed infants, were evaluated for in vitro adhesion, competitive adhesion and
immunomodulatory properties. Knowledge of such properties is important when considering specific circumstances
when these strains might be used clinically.
Methodology and results: The Caco-2 cell line was used for adhesion assays and for competitive adhesion assays
against Escherichia coli O157:H7. Lactobacillus rhamnosus GG was used as the reference strain for adhesion assays.
The immunomodulatory activities of the five strains were evaluated by determining the levels of the inflammatory
cytokines IL-6, IL-12 and TNF-α, and of the immunoregulatory cytokine IL-10, produced by bacterial-activated THP-1
cells after 6, 12 and 24 h of stimulation. In the cell-adhesion assays, all five strains showed high adhesion properties.
For UBU09, UBU34 and UBU37, adhesive capacity was higher than that of the reference strain. All strains except
UBU03 showed the ability to inhibit adhesion of E. coli O157:H7 to Caco-2 cells. All strains induced IL-6 production but
not IL-12 production. UBU03 and UBU09 could induce only one cytokine IL-6. UBU06 and UBU34 could each induce
two (IL-6/IL-10 and IL-6/TNF-α, respectively). UBU37 could induce three cytokines (IL-6/TNF-α /IL-10).
Conclusion, significance and impact of study: These five probiotic L. rhamnosus strains with high adhesion
properties and with different in vitro cytokine induction profiles should be investigated further in different immunological
conditions to identify appropriate circumstances for their clinical use.