Response of monocytes to GM-CSF and IL-4 is altered by EBV infection.

(A) Light microscopy images of purified monocytes cultured for 6 days in medium containing 1000 U/mL recombinant GM-CSF. Most of the cells in the control cultures adhered firmly to the plastic, whereas virtually all the EBV-infected cells detached and formed tight, medium-sized clumps. Two of 10 representative cultures initiated with monocytes from 2 donors are shown. (B) Cell recovery of purified monocytes cultured with 1000 U/mL recombinant IL-4. Cells cultured in IL-4 alone died within 5 to 6 days, as expected. The recovery of viable cells at day 4 was 5- to 10-fold lower in EBV-infected cultures than in uninfected controls. Results from 2 experiments performed in parallel are shown. (C) Surface expression of CD14 was compared on control or EBV-infected cells by immunostaining and FACS analysis. Down-regulation of CD14 was delayed in EBV-infected DCs. Results from 1 of 3 experiments are shown.