Heat inactivation of fetal calf serum is not required for in vitro measurement of lymphocyte functions.

This study was undertaken to test whether fetal calf serum (FCS) must be heat inactivated before use in tissue culture. We tested various immune functions of lymphocytes growing in medium containing non-treated and heat-inactivated FCS. The data clearly show that heat inactivation of the serum is not mandatory. In some cases, the addition of untreated FCS resulted in elevated response levels, while maintaining immune function specificity.