Preliminary characterization of jejunocyte and colonocyte cell lines isolated by enzymatic digestion from adult and young cattle.

In the present study we developed an enzymatic approach (through the use of collagenase and dispase) to isolate bovine intestinal epithelial cells. Using this method, freshly isolated jejunocytes could be distinguished from simultaneously isolated colonocytes, as the jejunocytes specifically exhibited the small intestinal peptidase gene transcript, as well as an active alkaline phosphatase. The transformation of both types of cell suspension was performed by retroviral infection, using reproduction-defective viruses bearing the gene coding for the large T antigen of the leukaemia simian virus (SV40). The success of the transfection was demonstrated by (1) a significant increase in cell passage numbers (52-53 vs. 7 passages for non-transfected cells), (2) the detection of both the large T transcript and the large T antigen in transformed cells. Possible contamination and progressive substitution of bovine primocultures by non-bovine lineages available in the laboratory was excluded, as the transformed cells presented a bovine typical karyotype. Most transfected cells kept an epithelial morphology after transformation. They also maintained the expression of FABP and enterocyte specific enzymes (brush-border associated maltase and IAP). However, levels of specific activity of these enzymes were low, suggesting that cell differentiation is not completely achieved under the applied culture conditions.