Oral infections of mice with 2؉ and Mg 2؉ ion-independent. The binding avidity of Ym1 to GlcN oligosaccharides was enhanced by more than 1000-fold due to the clustering effect. Specific binding of Ym1 to heparin suggests that heparin/heparan sulfate may be its physiological ligand in vivo during inflammation and/or tissue remodeling. Although it shares ϳ30% homology with microbial chitinases, no chitinase activity was found associated with Ym1.

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SummaryBoth viral effect and immune-mediated mechanism are involved in the pathogenesis of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) infection. In this study, we showed that in SARS patient sera there were autoantibodies (autoAbs) that reacted with A549 cells, the type-2 pneumocytes, and that these autoAbs were mainly IgG. The autoAbs were detectable 20 days after fever onset. Tests of non-SARS-pneumonia patients did not show the same autoAb production as in SARS patients.

We employed a genetic approach to study protein glycosylation in the procyclic form of the parasite Trypanosoma brucei. Two different mutant parasites, ConA 1-1 and ConA 4-1, were isolated from mutagenized cultures by selecting cells which resisted killing or agglutination by concanavalin A. Both mutant cells show reduced concanavalin A binding. However, the mutants have different phenotypes, as indicated by the fact that ConA 1-1 binds to wheat germ agglutinin but ConA 4-1 and wild type do not. A blot probed with concanavalin A revealed that many proteins in both mutants lost the ability to bind this lectin, and the blots resembled one of wild type membrane proteins treated with PNGase F. This finding suggested that the mutants had altered asparaginelinked glycosylation. This conclusion was confirmed by studies on a flagellar protein (Fla1) and procyclic acidic repetitive protein (PARP). Structural analysis indicated that the N-glycan of wild type PARP is exclusively Man 5 GlcNAc 2 whereas that in both mutants is predominantly a hybrid type with a terminal N-acetyllactosamine. The occupancy of the PARP glycosylation site in ConA 4-1 was much lower than that in ConA 1-1. These mutants will be useful for studying trypanosome glycosylation mechanisms and function.