Table 1.

The relative affinity of F/HN and HA Rostock pseudotyped LV for binding of sialylated glycans, using inhibition of hemagglutination

Glycan				Inhibition of hemagglutination (pMol per reactiona)
				Lentiviral pseudotype
Name	Structure	Lectin	Linkage	F/HN	HA Rostock
6ʹ-Sialyl-LacNAc		SNA	$\alpha$2,6	none detected	none detected
LSTc				none detected	none detected
3ʹ-Sialyl-LacNAc		MAI	$\alpha$2,3	4.5 ± 2.1 × 104	4.5 ± 2.1 × 104
LSTd				2.8 ± 1.3 × 103	4.5 ± 2.1 × 104
Asialo		–	none	none detected	none detected

Hemagglutination of red blood cells (RBCs) by pseudotyped LV was determined in the presence of various glycans. The structure of each glycan is shown following the SNFG system: sialic acid (purple diamond), galactose (yellow circle), N-acetylglucosamine (blue square), and N-acetylgalactosamine (yellow square). The glycosidic linkage, and expected lectin binding (Sambucus nigra agglutinin [SNA] or Maackia amurensis [MAI or MAII]), are also shown for each glycan. A range of concentrations was used to determine the relative potency of each glycan to compete with RBC for LV binding. The minimum pMol glycan per reaction to inhibit hemagglutination is indicated. Values indicate mean pMol required to inhibit hemagglutination, calculated from two independent experiments, with different batches of RBCs (Table S2). For each experiment, both pseudotypes were assayed in parallel following HA titration with each RBC batch. Inhibition was determined by observation of RBC pellets matching control reactions in the absence of vector. The maximum pMol of each glycan investigated was dependent on availability and solubility. LSTc and Asialo glycans were investigated to a maximum of 2.5 × 104 pMol. 6ʹ-Sialyl-LacNAc, 3ʹ-Sialyl-LacNAc, and LSTd glycans were investigated to a maximum of 1.6 × 105 pMol.

^aMean ± standard deviation.