Table 1.

Quantitative internalization assay results for VZV gE and gI

Incubation time (min)agI alonebgI with gEcgE alonedgE with gIe
RadioactivityInternalizationRadioactivityInternalizationRadioactivityInternalizationRadioactivityInternalization
cpmfCorrected cpmg%h% (mean ± SD)icpmCorrected cpm%% (mean ± SD)cpmCorrected cpm%% (mean ± SD)cpmCorrected cpm%% (mean ± SD)
 0 (without trypsin)35,23533,27210010034,93633,65510010034,94233,60710010027,02625,912100100
 0 (with trypsin)1,9630001,2810001,3350001,114000
1516,20614,24342.843.3  ±  0.820,87419,59358.258.4  ±  0.911,68610,35130.830.7  ±  0.515,23614,12254.555.2  ±  0.9
3017,34415,38146.246.3  ±  0.721,65620,37560.560.5  ±  0.511,96110,62631.631.9  ±  115,80614,69256.756.8  ±  0.6
4517,58015,61746.947.3  ±  0.722,01920,73861.661.8  ±  0.912,19710,86232.332.5  ±  0.516,01314,89957.557.3  ±  0.8
6017,64415,68147.147.4  ±  0.621,78620,50560.961.1  ±  0.811,78010,44532.132.2  ±  0.515,85814,74456.956.9  ±  0.9
  • a The cells were incubated for the time indicated at 37°C following incubation with antibody during the endocytosis assay. The cells were either left untreated or were treated with trypsin, which removes all the surface proteins, before (0 min) or after the incubation times indicated at 37°C. The proteins which were left after trypsin treatment represented the internalized protein.

  • b The VZV gI gene was transfected into HeLa cells, and the gI protein was precipitated with anti-gI MAb 6B5.

  • c The VZV gI gene and the VZV gE gene were transfected into HeLa cells, and the gE:gI complex was precipitated with MAb 6B5.

  • d The VZV gE gene was transfected into HeLa cells, and the gE protein was precipitated with anti-gE MAb 3B3.

  • e The VZV gE gene and the VZV gI gene were transfected into HeLa cells, and the gE:gI complex was precipitated with MAb 3B3.

  • f The radioactivity of each protein in counts per minute was determined with an Instantimager.

  • g The radioactivity of each protein was corrected by subtracting the background radioactivity measured in the control sample (incubation time, 0 min; with trypsin).

  • h The percentage of protein internalized was determined by dividing the corrected counts per minute at each time point by the corrected counts per minute of the total protein present on the surface at the beginning of the assay (time, 0 min; without trypsin), and multiplying this value by 100.

  • i These values represent data collected for this experiment and three additional independent experiments conducted in a similar manner, as described in Materials and Methods.