The accessibility of short antigenic peptides displayed on the yeast cell surface [19] [20] [21] was confirmed in this study with fluorescence confocal microscopy, as exemplified by the antigenic clones G-29 (93 aa) and G-46 (32 aa), from the screening against the goat antisera (Fig. S6) . As shown in the figure, the antigenic peptides were localized on the outer surface of the membrane, and well accessible to the antibodies in the complex antisera.