A reactivity that was completely lost upon periodate treatment. Oxidation also affected some IgG mAb-reactive constituents, but it left completely intact other components, inclusive of those corresponding to the 157 and 138 kDal bands, in keeping with the expected resistance of b1,3 glucan to periodate oxidation. By immuno-affinity purification onto a mAb 2G8-Protein ASepharose column, the IgG mAb-reactive material was isolated from culture supernatants yielding a fraction that comprised at least two of the reactive bands observed in total fungal secretion, in particular the component with an apparent molecular weight of 138 kDal. Interestingly, this fraction was also recognized by sera from mice immunized with the Lam-CRM vaccine, suggesting that at least some of the anti-b-glucan antibodies generated by this protective vaccination have the same specificity as the protective IgG mAb. To gain insights into protein constituents associated with the IgG-reactive, secreted b-glucan, the two bands of 138 and 157 kDal, best recognizable in the fungal secretion, were excised from the gels, subjected to controlled proteolysis with trypsin and analyzed by mass spectrometry. Following this approach, the analyses of both bands yielded several peptide mass signals with signal/noise ratio.5. A MASCOT search was carried out against the fungal protein sequences in the NCBInr database and Als3 was clearly identified as a component of both bands. Furthermore, in the 138 kDal band the search also identified the Hyr1 protein. The majority of the signals present in the mass spectra matched with the sequences of the protein identified. Overall, these results, coupled with those illustrated in the previous sections, Butenafine hydrochloride indicated that b-glucan antigenic motifs bound by the two mAbs are expressed in the cell wall and at cell surface, and are secreted into the external milieu. However, significantly more IgG-reactive components are secreted, and these include those associated with Als3 and Hyr1, two GPI-anchored cell wall proteins that exert critical roles in cell wall assembly, growth and fungal virulence. A number of experimental 3,4,5-Trimethoxyphenylacetic acid approaches were used to gain insights into the cell wall ligand recognized by the two mAb. These consistently indicated that the protective IgG mAb had a quite selective specificity for b1,3- linked glucose sequences.