Host-mediated inhibition of rat bladder cancer growth by cyclophosphamide and purine salvage pathway-related enzyme activity of lymphocytes.
In ACI/N rats pretreated with cyclophosphamide (CY) growth of the bladder cancer, BC-47, and adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in lymphocytes were investigated to clarify the possible antitumor effect via the immune system of the chemotherapeutic agent. A single dose of 50 mg/kg of CY with the tumor implantation 3 days later gave rise to tumor regression following temporary progression around day 15 and significant increase of peripheral lymphocytes with higher PNP activity on days 7 to 10 of the tumor implantation. In the thymus such lymphocytes increased 3 days earlier. The antitumor effect was not demonstrated in athymic nude mice. In the light of the results and elimination of suppressor T precursors by CY, it was postulated that T lymphocytes with higher PNP activity act as effector cells in the antitumor immunity whereas suppressor T precursors belong to the cell population with lower PNP activity.
D000243:Adenosine Deaminase / Q000097:blood*; D000818:Animals; D003520:Cyclophosphamide / Q000627:therapeutic use*; D007700:Kinetics; D007958:Leukocyte Count; D008214:Lymphocytes / Q000201:enzymology / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D009700:Nucleoside Deaminases / Q000097:blood*; D010430:Pentosyltransferases / Q000097:blood*; D011683:Purine-Nucleoside Phosphorylase / Q000097:blood*; D051381:Rats; D011912:Rats, Inbred ACI; D013601:T-Lymphocytes / Q000276:immunology; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy / Q000276:immunology*
D003520:Cyclophosphamide; D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase