We have investigated the chemical structure of the antigenic determinant of Candida krusei cell-wall mannan. Acetolysis of the mannan, obtained by extraction with alkali and purified as copper complex, gave five oligosaccharides (from mono- to pentasaccharide) and a minor amount of an octasaccharide. Partial acetolysis of the mannan gave a large amount of mannooctaose. We have examined the inhibition by these oligosaccharides of the precipitin reaction between anti-Candida krusei serum and homologous mannan, and found that the mannooctaose was the most effective inhibitor. Results obtained by proton magnetic resonance spectroscopy, methylation analysis, and other structural studies of Candida krusei mannan, suggest that the octasaccharide possesses six alpha (1-2) linkages and one alpha (1-6) linkage located in the middle of the chain, and that this mannooctaose may be responsible for the specificity of Candida krusei cell-wall mannan.

Antigens, Fungal↗

PubMed1982

Immunological characterization and structural studies of normal fecal antigen-1 related to carcinoembryonic antigen.

Normal fecal antigen-1 (NFA-1), which is a carcinoembryonic antigen (CEA)-related glycoprotein with a mol. wt of 20,000-30,000, was purified from normal adult feces by immuno-adsorption, gel filtration and ion exchange chromatography. Highly purified NFA-1 was partially cross-reactive with CEA but antigenically unrelated to nonspecific cross-reacting antigen (NCA) which was also cross-reactive with CEA. NFA-1 also had a unique determinant not present in CEA or other related antigens including NCA. In a solid-phase RIA system, the reactivity of NFA-1 with a specific anti-CEA antiserum was much stronger than that of NCA. Although digestion with Pronase E did not affect the antigenicity of NFA-1, reduction and alkylation destroyed its antigenic reactivity. The total amount of carbohydrate in NFA-1 was 13.3%, compared to 52.4% in CEA and 21.6% in NCA. The amino acid composition of NFA-1 was similar to that of CEA. The sequence of the first 10 NH2-terminal amino acids in NFA-1 was Ala-Glu-Pro-Pro-Lys-Pro-Phe-Ile-(Thr)-Ser. This was totally different from that of the first NH2-terminal amino acids of CEA isolated from tumor tissue.

Amino Acid Sequence↗

PubMed1982

Antigenic characterization of Cryptococcus neoformans serotypes and its application to serotyping of clinical isolates.

Antigenic analysis of the four serotypes of Cryptococcus neoformans was carried out by slide agglutination with reciprocal adsorption methods. With this procedure the antigenic patterns of the serotypes were established. Serotypes A and D had antigenic factors 1, 2, 3, 7 and 1, 2, 3, 8, respectively. Serotypes B and C were found to have antigenic factors 1, 2, 4, 5 and 1, 4, 6, respectively. Factor sera, prepared according to the antigenic patterns demonstrated by adsorption studies, proved to be useful for rapidly and accurately identifying C. neoformans serotypes. Some patterns similar to those of the C. neoformans serotypes were observed in five other Cryptococcus species and two Candida species. The proton magnetic resonance spectra of polysaccharides from the C. neoformans serotypes correlated well with their antigenic characteristics. Phenol oxidase test reactions and growth at 37 degrees C were useful criteria for determining which yeasts should be chosen for clinical application of factor sera for serotyping of C. neoformans. Sixty-two Japanese isolates of C. neoformans were serotyped. Fifty-eight of these isolates were serotype A, three were serotype A-D, and one was serotype D.

Agglutination Tests↗