The study shows that synthetic thymic peptides like Thymogen can boost certain immune cell functions in lab tests, especially making neutrophils better at swallowing targets and producing reactive oxygen species, but the effects were seen at a very high concentration (10 mM) and only in isolated blood cells, not in people.

The direct action of synthetic peptide preparations, analogous to thymic hormones, on the functions of phagocytic cells was studied. The preparations Thymogen, Neogen and Thymodepressin in a dose of 10 mM produced a stimulating effect on the ingestive activity of the neutrophil, but not monocytic, population. All three preparations also enhanced the formation of oxygen metabolites registered in the luminol-dependent chemiluminescent analysis. The characteristics of spontaneous chemiluminescence (CL) reflecting the basal level of the synthesis of the active forms of oxygen and CL induced by opsomized zymosan significantly increased also in those cases when the preparations were used in a dose of 10 mM. The level of the synthesis of hydrogen peroxide in individual cells could be appraised by the intensity of the luminescence of dichlorofluorescein diacetate (DCF-DA), evaluated with the use of flow cytometry. All preparations produced a stimulating effect on the formation of hydrogen peroxide in monocytes. The reaction of neutrophils was even more active: Neogen (10 mM) produced the twofold change in the intensity of the luminescence of DCF-DA) in neutrophils, Thymogen and Thynodepressin increased the average intensity of the luminescence of DCF-DA by 80% and 60%, respectively.