Fig. 4. Immunogold labeling of PCTV showing VAMP7 and either Sar1 or rBet1 to be present on the same membrane as shown by electron microscopy. PCTVs were placed on formvar-coated Nickel grids and exposed to pre-immune rabbit IgG (A), anti-Sar1 and anti-VAMP7 (B) or anti-rBet1 and anti-VAMP7 antibodies (C). Rabbit anti-VAMP7 antibodies were labeled with 15 nm immunogold particles. Rabbit anti-Sar1 and mouse anti-rBet1 antibodies were labeled with 10 nm immunogold particles. Bars, 100 µm (A); 80 µm (B,C).