Abstract There is no cell proliferation in very sparcely plated chick embryo cell cultures. Substituting conditioned medium or adding of ethanol‐fixed homologous cells to the cultures accelerates cell colony growth. The mechanism for the mitogenic action of fixed cells is considered to be the contact stimulation of cell proliferation, and addition of extra cells to sparse culture is believed to mimic the cell micro‐environment existing in subconfluent cultures. The role of diverse cell—cell contacts in cultured cell growth regulation is discussed. The procedure used (addition of ethanol‐fixed cells) may improve normal cell cloning techniques.
The growth rate of chick embryo cells in slowly proliferating cultures is activated after substitution of conditioned medium by fresh one with serum. After cell replanting, the stimulation of cell proliferation takes place in both media with the same effectiveness. In serum-less medium replanted cells do not adhere to glass and die. The results suggest that cells reversibly lose their dependence upon serum growth factors and population density, as a result of replanting, but retain anchorage-dependence for growth.
In sparsely seeded (1.10(3) cells/sm2) chick embryo cell cultures no cell proliferation commonly occurs. However, such factors as increasing cell density, a conditioned medium, or addition of ethanol fixed homologous cells to the culture may accelerate the cell growth. The mitogenic action of fixed cells serves as a contact stimulation of cell proliferation (Gasparian, Grigorian, 1989, 1990). Distant and contact cell-to cell interactions, that involve soluble and insoluble cell derived mitogens, are supposed to operate during the log phase of culture growth. The addition of an excess of cells to the previously sparse culture may mimic the cell microenvironment commonly existing in subconfluent cultures. The role of diverse cell-to cell contacts in the cell growth regulation is discussed. The addition of ethanol-fixed cells may improve the cell cloning technique.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
