In mice, feeding dried yeast that makes the immune‑boosting peptide thymosin‑alpha‑1 (Tα1) raised the number of CD8 + T‑cells, especially in animals whose immune systems were weakened, showing that oral Tα1 can have a real immunomodulatory effect, though this is an animal study and not yet proven in people.

To investigate the immunological function of a yeast expression system for thymosin alpha1 (Talpha1). A constructed Talpha1 yeast expression system was used to investigate the immunological function of orally administered Talpha1. Dried yeast containing three different concentration of Talpha1 was fed to normal Balb/c mice and other Balb/c mice whose immunities were inhibited in advance by cyclophosphamide. Synthesized Talpha1 peptide was used as positive control and dried yeast with empty plasmid was used as negative control. CD4(+) and CD8(+) levels were detected by flow cytometry assay. TNF-alpha, IFN-gamma, IL-2, IL-6 and IL-10 levels were detected by liquid chip. In normal Balb/c mice or immune inhibition Balb/c mice, CD8(+) levels were significantly increased. Especially in immune inhibition Balb/c mice, CD8(+) levels in synthesized Talpha1 group (18.77%+/-4.72%), small dose group (13.48%+/-6.17%) and large dose group (22.74%+/-1.09%) were significantly higher than that in empty yeast control group (7.49%+/-2.14%). Orally administered Talpha1 has its certain immunomodulatory function.