Figure 2. HSV-1 gE, HCMV gp68 and HCMV gp34 interfere with host FcγR activation upon opsonization of cells with polyclonal immune IgG.
(A) The HSV vFcγR gE inhibits FcγRIIIA and FcγRIIA activation but fails to inhibit FcγRI. Human MRC-5 fibroblasts were infected with 2 PFU/cell of HSV-1 strain F wt and ΔgE for 24 h. Cells were opsonized with Cytotect at different concentrations for 30 min. After removing of unbound antibodies with D-MEM 10% (vol/vol) FCS, 1×105 BW:FcγR-ζ transfectants per well were added and co-cultivated overnight. BW:FcγR activation was determined by measuring mIL-2 by ELISA. Three independent replicates were measured; means with standard deviations (error bars) are shown for 4 independent experiments. (B) HCMV vFcγR gp68 interferes with FcγRIIIA, FcγRIIA and FcγRI activation. MRC-5 cells were infected with HCMV HB5 wt virus or HB5Δgp68 (2 PFU/cell) for 72 h. Fibroblasts were opsonized with Cytotect at different concentrations for 30 min. After removing of unbound antibodies by washing, 1×105 BW:FcγR-ζ transfectants were added per well. Measurement of mIL-2 in supernatants after 16 h of co-cultivation of reporter cells with targets was performed by ELISA. Values are presented in the graphic as OD 450 nm. Three independent wells were measured; means with standard deviations (error bars) are shown for 4 independent experiments. Significance of results (Student's t-test) are presented in Table S1 as *: p<0.05 **: p<0.01 ***: p<0.001. (C) HCMV vFcγR gp34 interferes with FcγRIIIA, FcγRIIA and FcγRI activation. As in (B) but MRC-5 cells were infected with HCMV HB5ΔIRL, HB5ΔIRLΔgp34 or HB5ΔIRLΔgp68/Δgp34 (2 PFU/cell) for 72 h. (D) gp34 and gp68 interfere with FcγR activation in AD169varL infected cells. As in (B) but MRC-5 cells were infected with AD169varL wt, AD169varLΔgp68, AD169varLΔgp34 or AD169varLΔgp68/Δgp34.