Two New Serum Free and Protein Free Cell Strains, Derived from HEp-2 Cell Line: Cultural Conditions and Proliferation Activity

Two new cell strains – HEp-2-Plovdiv E and HEp-2-Plovdiv F were derived from the HEp-2 cell line. They could be cultivated indefinitely in vitro in DMEM/Ham’s F12 1:1 medium. These are serum-free and protein-free cultures because they grown only in medium that is chemically defined. Serum-free cultures could be distinguished by morphological characteristics, growth dynamics, sensitivity to trypsinization, prolife-ration activity and doubling time. The number of cell population’s doublings of the initial carcinoma cell line and the two serum-free cultures was calculated. The dynamics of cell proliferation was investigated and doubling time for HEp-2 cell line (22.6 h), HEp-2-Plovdiv F strain (25.8 h) and HEp-2-Plovdiv E strain (28.4 h) was calculated. DMSO of 7 % was added in the growth medium for storage in liquid nitrogen. Optimized parameters for cultivation and subcultivation of the cell cultures are suggested. Possible ways of application of the new serum free cell cultures, based on preliminary studies for viral cultivation and detection of serum autoantibodies are discussed.