Sialic Acid Expression in the Mosquito Aedes aegypti and Its Possible Role in Dengue Virus-Vector Interactions

Figure 3

DENV interaction with Ae. aegypti SG. (a) DENV interaction with Ae. aegypti SGs. SGs from Ae. aegypti were incubated with DENV and stained with anti-DENV E antibody and rhodamine-coupled anti-IgG antibody. (b) DENV-SG competence assays using ConA, LCH, and SNA lectins, which were added to SG before incubation with DENV. The interaction with DENV was blocked when DENV was incubated in the presence of lectins that recognized Sia. With LCH and ConA lectins, the magnification = 10x and with SNA lectin = 20x. Scale bar = 10 μm. (c) DENV-SG interaction in the absence or presence of sialidase. SGs were untreated or pretreated with C. perfringens sialidase for 30 min before adding DENV. The DENV-SG interactions in the presence of Sia competitors, fetuin (1 mM) and free Sia (200 nM), are also shown, where the DENV-SG interaction was blocked. (d) DENV-SG interaction in SGs pretreated with trypsin for 5, 15, or 30 min before adding DENV. There was a decrease in the DENV-SG interaction after 15 min, and it was lost completely at 30 min. Scale bar = 10 μm. Blue: nuclei stained with DAPI. Red: DENV stained with an antibody against viral protein E and a secondary antibody coupled to rhodamine. Green: (FITC) SNA lectin interaction.

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