*4.2. Cell Lines and Cell Culture*

The study involved the following normal, non-cancerous NIH/3T3 (fibroblasts) and J774E.1 (macrophages) murine cell lines and a panel of canine cancer cell lines: CLBL-1 (B-cell lymphoma), GL-1 (B/T-cell leukemia), CLB70 (B-cell chronic lymphocytic leukemia) and CNK89 (NK-cell lymphoma). The NIH/3T3 and J774E.1 cell lines were bought from the American Type Culture Collection (ATCC, Rockville, MD, USA). CLBL-1 was obtained from Barbara C. Ruetgen from the Institute of Immunology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria [40], GL-1 was obtained from Yasuhito Fujino and Hajime Tsujimoto from the University of Tokyo, Department of Veterinary Internal Medicine [41,42] while CLB70 [43] and CNK89 (Grudzie ´n et al., in press) were established in our laboratory.

The cell lines were maintained in RPMI 1640 (J774E.1, NIH/3T3, CLBL-1 and GL-1) (Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland) or Advanced RPMI (Gibco, Grand Island, NY, USA) (CLB70 and CNK89) culture medium supplemented with 2 mM L-glutamine (Sigma Aldrich, Steinheim, Germany), 100 U/mL penicillin, 100 μg/mL streptomycin (Sigma Aldrich, Steinheim, Germany), and 10–20% heat-inactivated fetal bovine serum—FBS (Gibco, Grand Island, NY, USA).
