Thymosin α1 application augments immune response and down-regulates tumor weight and organ colonization in BALB/c-mice

The immunomodulatory and antimetastatic/antitumor activity of thymosin α1 (Tα1) was evaluated in BALB/c-mice. Daily subcutaneous application (7 consecutive days, 0.01–10 μg of Tα1/injection per mouse) upregulated the number of thymocytes and peripheral blood cells in tumor bearing mice. To check the influence of Tα1 treatment on growth of experimental metastases, RAW H10 lymphosarcoma cells or L-1 sarcoma cells were intravenously injected into BALB/c-mice to establish liver or lung metastases. Local tumor growth was induced by subcutaneous injection of L-1 sarcoma cells. Tα1 was subcutaneously administered daily for 7 consecutive days starting 24 h after tumor cell challenge. Organ colonization, as well as local tumor growth, were investigated on day 14 after tumor cell inoculation, and demonstrated a statistically significant (P<0.05) reduction of experimental liver and lung metastases and local tumor growth for Tα1 treated mice.