Immunomodulatory potential of four candidate probiotic strains from plant and animal origin using comparative genomic analysis.

Probiotic strains from different origins have shown promise in recent decades for their health benefits, for example in promoting and regulating the immune system. The immunomodulatory potential of four strains from animal and plant origins was evaluated in this paper based on their genomic information. Comparative genomic analysis was performed through genome alignment, average nucleotide identity (ANI) analysis and gene mining for putative immunomodulatory genes. The genomes of the four strains show relative similarities in multiple regions, as observed in the genome alignment. However, ANI analysis showed that LM1 and SK152 are the most similar when considering their nucleotide sequences alone. Gene mining of putative immunomodulatory genes studied from WCFS1 yielded multiple results in the four potential probiotic strains, with SK151 showing the largest number of genes at around 74 hits, followed by PF01 at 41 genes when adjusted for matches with at least 30 % identity. Looking at the immunomodulatory genes in each strain, SK151 and PF01 may have wider activity, covering both immune activation and immune suppression, as compared to LM1 and SK152, which could be more effective in activating immune cells and the pro-inflammatory cascade rather than suppressing it. The similarities and differences between the four species showed that there is no definitive trend based on the origin of isolation alone. Moreover, higher percentage identities between genomes do not directly correlate with higher similarities in potential activity, such as in immunomodulation. The immunomodulatory function of each of the four strains should be observed and verified experimentally in the future, since some the activity of some genes may be strain-specific, which would not be identified through comparative genomics alone.