Generation of potent neutralizing human monoclonal antibodies against cytomegalovirus infection from immune B cells

Funaro, Ada; Gribaudo, Giorgio; Luganini, Anna; Ortolan, Erika; Lo Buono, Nicola; Vicenzi, Elisa; Cassetta, Luca; Landolfo, Santo; Buick, Richard; Falciola, Luca; Murphy, Marianne; Garotta, Gianni; Malavasi, Fabio

EBV alone (BASIC) (Figure 1 ). Different experimental settings were compared in pools of cells derived from 5 healthy donors, to minimize donor variability. The results clearly demonstrated that activation of CD22 + B-lymphocytes before EBV exposure leads to improved immortalization, as highlighted by the viability of cells following EBV transformation which is significantly higher than that obtained with both combined and basic conditions (Figure 2A) . The short-term viability of B lymphocytes immortalized following the basic procedure is higher than those of B lymphocytes treated with the combined procedure. This is attributable to the polyclonal activation elicited by EBV itself which is not paralleled by an efficient immortalization. Indeed, it is well documented that exposure of human B-lymphocytes to EBV results in cell death of a proportion of cells and that B-lymphocytes are activated but not immediately immortalized following exposure to EBV [21] [22] [23] .