title: Anti-beta-glucan antibodies in healthy human subjects.
abstract: Previous data by our group demonstrated the antifungal efficacy of a vaccine consisting of laminarin (beta-(1,3)-glucan), conjugated with diphtheria toxoid, which generated protective anti-laminarin antibodies in mice. In this paper, we sought for the presence, isotype and subclass composition of natural anti-laminarin antibodies in an unselected population of human healthy subjects, in a comparison with antibodies directed against beta-(1,6)-glucan (pustulan) and branched beta-(1,3/1,6)-glucan (Pool 1) and mannan from Candida albicans. Almost all subjects showed detectable levels of anti-beta-glucan antibodies, with IgG largely prevailing on IgM, little, if any, IgA and no IgE. However, the titer of anti-beta-glucan antibodies was overall about 1log lower than that of anti-mannan antibodies of the corresponding isotype. In particular, the level of anti-laminarin IgG was the lowest one, its geometrical mean titer (95% confidence interval, CI) being 1838 (1245-2714) as compared to 8157 (6067-10,931) and 3940 (2911-5332) for pustulan and Pool 1 fungal glucan, respectively. Analysis of IgG subclass composition showed that IgG2 was the prevalent subclass against any antigen, and again the concentration of anti-laminarin IgG2 was the lowest one, its geometrical mean concentration being 0.13 (0.07-0.24)microg/ml as compared to anti-pustulan and anti-Pool 1 glucan and mannan IgG2 levels, which were 0.33 (0.2-0.5), 1.35 (0.9-2.0), and 36.1 (25.2-51.3)microg/ml, respectively. These data show that anti-laminarin antibodies are present at low levels in humans as compared to other anti-beta-glucan and, mostly, anti-mannan antibodies, and suggest that a protective antifungal vaccination in humans should attempt to tip the balance of antifungal antibodies in favour of the anti-laminarin ones.
authors.affiliation: Department of Infectious, Parasitic and Immune-mediated Diseases, Medical Mycology Unit, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Chiani
authors.forename: C
authors.initials: C
authors.lastname: Bromuro
authors.forename: A
authors.initials: A
authors.lastname: Cassone
authors.forename: A
authors.initials: A
authors.lastname: Torosantucci
mesh_terms: D000328:Adult; D000908:Antibodies, Fungal / Q000097:blood / Q000276:immunology*; D000946:Antigens, Fungal / Q000097:blood* / Q000276:immunology; D002176:Candida albicans / Q000276:immunology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007073:Immunoglobulin E / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008351:Mannans / Q000097:blood / Q000276:immunology*; D008875:Middle Aged; D055815:Young Adult; D047071:beta-Glucans / Q000097:blood / Q000276:immunology*
chemical_list: D000908:Antibodies, Fungal; D000946:Antigens, Fungal; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008351:Mannans; D047071:beta-Glucans; D007073:Immunoglobulin E