Gal-1 differently affects Syn-1– and Syn-2–pseudotyped viruses. A) HEK293T cells were infected by Syn-1–pseudotyped viruses (triplicate samples) in the presence of PBS (virus only, white bars), increasing doses of recombinant Gal-1 (gray bars), or 4 μM Gal-1 + lactose (dark gray bars). Mean normalized luciferase activities ± sem was calculated, and the results of 3 independent experiments are expressed as fold-change in infectivity. **P < 0.01 (1-way ANOVA). B) HEK293T cells were infected with Syn-1– or Syn-2–pseudotyped viruses in the presence of PBS (white bars), 4 μM Gal-1 (gray bars), or 4 μM Gal-1 + lactose (dark gray bars). The mean normalized luciferase activity ± sem was calculated. Lac, lactose. Results are representative of 3 independent experiments. Ns, not significant ***P < 0.001 (2-way ANOVA).