Sharon Blumer

Characterization of immunoglobulin classes of human antibodies to cryptococcus neoformans.

Immunoglobulin G (IgG), immunoglobulin M (IgM) and immunoglobulin A (IgA) levels were determined by radial immunodiffusion techniques in sera from 11 patients with cryptococcosis. Most specimens showed increased levels of IgM. Studies with fluorescein-labeled monospecific antihuman IgG and IgM, however, indicated that IgG was the immunoglobulin reactive in the indirect fluorescent antibody (IFA) test. In addition, cross-reacting sera from mycotic infections other than cryptococcosis were also shown to contain IFA antibodies of the IgG class. Sera treated with 2-mercaptoethanol continued to react in both the IFA test and the tube agglutination test. No correlation could be established between IgG and IgM concentrations and serological reactivity in the sera evaluated in this study.

Variation in enzymatic activities among strains of Histoplasma capsulatum and Histoplasma duboisii

The hydrolytic activities of 10 strains of Histoplasma capsulatum and 10 of H. duboisii were studied on gelatin, tyrosine and urea substrates. The data revealed that species specific differences in enzymatic activity for these substrates did not occur. Consequently, these tests cannot be used to separate the 2 species. Definitive identification of H. duboisii cultures still requires that animal inoculation be used to demonstrate the large yeast form characteristic of this species.

Development and evaluation of agglutination and fluorescent antibody procedures for the identification of Cryptococcus neoformans.

Specific agglutinins and fluorescent antibodies were produced against Cryptococcus neoformans by adsorbing C. neoformans antibodies with cells of C. neoformans var. uniguttulatus, Candida albicans, and Candida curvata. Cross reactions and adsorption data revealed that C. neoformans, the saprophytic cryptococci and several species of Candida possessed common antigens. The agglutination test showed excellent sensitivity and was effective for the rapid and accurate identification of C. neoformans. The fluorescent antibody test was less sensitive and of limited value. The value of these findings, both from a diagnostic and taxonomic viewpoint, is discussed.

Effect of chitinase complex on the antigenicity and chemistry of yeast-form cell walls and other fractions of Histoplasma capsulatum and Blastomyces dermatitidis

Cell walls isolated from the yeast forms of 2 strains each of Histoplasma capsulatum and Blastomyces dermatitidis were treated for up to 3 weeks with an enzyme complex containing chitinase and β-1:3-glucanase. The release of glucose, protein, and amino-sugars from the cell walls was monitored. Cell walls of H. capsulatum lost about 25% of their dry weight as glucose, about 19% as amino-sugar (mainly free N-acetyl glucosamine), and about 6% as protein. Cell walls of B. dermatitidis lost only about 1% of their dry weight as glucose, about 22% as amino-sugar (mainly chitobiose), and about 6% as protein. Electron microscopy of intact yeast-form cells showed them to be extensively degraded by the enzyme complex. Complement fixation (CF) tests indicated that the enzyme treatments caused no substantial change in the antigenic specificity or sensitivity of the cell walls. However, concentrated culture filtrates of B. dermatitidis and the soluble fraction of H. capsulatum cell walls after chitinase treatment, show...