Precipitin Inhibition of Candida stellatoidea Antiserum with Oligosaccharides Obtained from the Parent Mannan.

Inhibition of immune precipitation with oligosaccharides obtained from Candida stellatoidea mannan has been used to provide more information about the haptenic groups of this serologically active polysaccharide. The oligosaccharides di-, tri-, tetra-, and a mixture of penta- and hexasaccharides were studied. The inhibitory activity of these materials was tested with two immune sera. With one serum, 0.8 mumole of the mixture of penta- and hexasaccharides inhibited the reaction by 87%, and, with the other serum, 0.4 mumole of the mixture inhibited the reaction by 99%. Monosaccharides were also tested with each antiserum and found to be noninhibitory. It is apparent that the mixture of oligosaccharides containing 5 to 6 mannose units was the most effective inhibitor. Since it is known that these oligosaccharides contain a predominance of alpha 1-2 linkages and lesser numbers of alpha 1-3 linkages, it is likely that these are important in the structural configuration of the antigenic determinants.