Growth-regulating influence of nonactivated resident macrophages on transformed and tumor cells in the in vitro contact interactions.

Susceptibility to cytostatic activity of nonactivated macrophages (Mph) of Syrian hamster embryo fibroblasts (HEF) transformed in vitro by BAV-3, SV40, RSV-SR, or spontaneously and of their in vivo selected variants was studied in dynamics (5 days of co-incubation). With the use of 3H-TdR incorporation test it was demonstrated that HEF transformed by BAV-3 appeared to be able to overcome the cytostasis at 4-5 day of the co-incubation with Mph, in contrast to deeply suppressed spontaneously transformed cells of STHE strain. HEF transformed by SV40, or RSV-SR appeared to be resistant to growth-inhibiting activity of Mph during almost all the 5-day period. The in vivo selected malignant variants of STHE cells were able to recover from cytostasis after 4-5 days of the co-incubation with nonactivated Mph, in contrast to low-malignant variant and to parental cell strain.