Result: Introduction of the N146D/S/Y mutations in plasmid M88 and P38.II by SDM did not significantly alter the EC and IC HBsAg production pattern, although a slight reduction in HBsAg secretion was observed for P38.II mutants, as reflected by the decreased HBsAg EC/IC ratio compared to that of wt HBsAg (5-8 versus 17) (Figure 3).

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Result: Mutants N146D/S/Y showed an expected non-glycosylated profile.

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Result: Particularly, mutations removing the N146 glycosylation site (N146D/S/Y) were found in 4.4% (2/45) and 6% (3/50) of OBI genotype B (OBIB) and genotype C (OBIC) sequences, respectively.

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