In this scenario, the antibodyaccessible b-1,3 glucan could be mostly represented by the glucan bound to the proteins of the outer cell wall, which is likely to undergo even marked variations during growth and morphologic changes, rather than the more invariant b-glucan of the inner cell wall skeleton. In this paper, we show that there is at least as much IgM- as IgG mAb-reactive b-glucan in C. albicans cell wall, as seen by ELISA using C. albicans b-glucan and EM of goldimmunolabelled sections of both yeast and hyphal cells of the fungus. Remarkably, however, the material secreted by growing fungal cells was much more reactive with the IgG than with the IgM mAb or substantially non reactive with the IgM antibody. This suggests that the secreted material is enriched with b1,3 glucan sequences as compared with b-glucan “stably” located in the cell wall. Among the secretory components recognized by the protective IgG mAb, two of them, Als3 and Hyr1, could be among the targets of the protective action of this mAb. Both these proteins belong to a major category of cell wall components, the GPIanchored proteins, which are covalently linked to b-glucan and include structural constituents, enzymes, adhesins and other components playing a crucial role in cell wall organization, stress response and virulence of the fungus. Both Als3 and Hyr1 are known to be actively secreted by C. albicans : their strong binding by the IgG mAb would also suggest that they are secreted with attached b-glucan, in particular b1,3 glucan, moieties. Relatively little is known about the functional properties of Hyr1 protein. It is activated 
during hyphal transition and upon exposure to macrophages or neutrophils and its expression has been shown to be under control of well-established hyphal regulatory pathways of this fungus. Overall, this protein is assumed to play a role in yeast to mycelial conversion of C. albicans. Relevant to the data shown in this study is a very recent report that members of the IFF protein family, to which Hyr1 belongs, play a role in Orbifloxacin fungus adherence. There is much more information on the structure and biological properties of Als3, and this is clearly relevant to the interpretation of the inhibitory and protective potential of our anti-b1,Labetalol hydrochloride 3-glucan IgG mAb. Als3 is encoded by the corresponding gene of the ALS gene family which code for structurally-related, high Mr cell surface and secreted glycoproteins.