Antibody interactions with the capsule of Cryptococcus neoformans

Citation
M. Feldmesser et al., Antibody interactions with the capsule of Cryptococcus neoformans, INFEC IMMUN, 68(6), 2000, pp. 3642-3650
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Immunology
Journal title
INFECTION AND IMMUNITY
ISSN journal
0019-9567 → ACNP
Volume
68
Issue
6
Year of publication
2000
Pages
3642 - 3650
Database
ISI
SICI code
0019-9567(200006)68:6<3642:AIWTCO>2.0.ZU;2-E
Abstract
Monoclonal antibodies to the encapsulated fungus Cryptococcus neoformans pr oduce different immunofluorescence (IF) patterns after binding to the polys accharide capsule, To explore the relationship between the IF pattern and t he location of antibody binding, two immunoglobulin hi (IgM) monoclonal ant ibodies (MAbs) (12A1 and 13F1) that differ in protective efficacy and IF pa ttern and one protective IgG1 MAb (2H1) were studied by IF and electron mic roscopy (ER I). Fixing C. neoformans cells in lung tissue for EM resulted i n significantly better preservation of the capsule than fixing yeast cells in suspension. The localization of MAbs 12A1 and 13F1 by immunogold EM diff ered depending on whether the MAb was bound to cells in cut tissue sections embedded in plastic or to cells in solution. In cut tissue sections, MAbs 12A1 and 13F1 bound throughout the capsule, whereas in solution both MAbs b ound near the capsule surface. To investigate whether antibody binding to t he C. neoformans capsule affected the binding of other primary or secondary reagents, various combinations of MAbs 12A1. 13F1, and 2H1 were studied by direct and indirect IF. The IF pattern and location of binding for MAbs 12 A1, 13F1, and 2H1 varied depending on the presence of other capsule-binding MAbs and the method of detection. The results show that (i) binding of MAb s to the C. neoformans polysaccharide capsule can modify the binding of sub sequent primary or secondary antibodies; (ii) the IgM MAbs bind primarily t o the outer capsule regions despite the occurrence of their epitopes throug hout the capsule; and (iii) MAb 2H1 staining of newly formed buds is reduce d, suggesting quantitative or qualitative differences in bud capsule.