Comparative studies on adult donor lymphocytes infected by EB virus in vivo or in vitro: origin of transformed cells arising in co-cultures with foetal lymphocytes.

Co-cultures were set up between equal numbers of mononuclear cells from the blood of EB virus-infected individuals, either acute IM patients or healthy seropositive adult donors, and foetal cord blood mononuclear cells of the opposite sex. The cell lines arising in the co-cultures were of mixed origin, with foetal cells predominating in many cases. In contrast, when mononuclear cells from seronegative adult donors were first infected with EB virus in vitro and then 5 to 12 days later co-cultured with a large excess of foetal cells of the opposite sex, the cell lines which arose were almost exclusively derived from the adult donor despite the fact that a small minority of the virus-infected adult cells released infectious virus capable of transforming the co-cultivated foetal cells. The experiments suggest that EB virus-infected cells present in the blood of IM patients and seropositive donors do not possess the capacity for unlimited in vitro growth shown by seronegative adult donor lymphocytes experimentally infected with the virus.