Your browser version may not work well with NCBI's Web applications. More information here...
1: J Immunol. 2001 Nov 15;167(10):5845-51.
Related Articles, Links
Click here to read
The capsular polysaccharides of Cryptococcus neoformans activate normal CD4(+) T cells in a dominant Th2 pattern.

Almeida GM, Andrade RM, Bento CA.

Programa de Imunobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.

Capsular components of Cryptococcus neoformans induce several deleterious effects on T cells. However, it is unknown how the capsular components act on these lymphocytes. The present study characterized cellular and molecular events involved in immunoregulation of splenic CD4(+) T cells by C. neoformans capsular polysaccharides (CPSs). The results showed that CPSs induce proliferation of normal splenic CD4(+) T cells, but not of normal CD8(+) T or B lymphocytes. Such proliferation depended on physical contact between CPSs and viable splenic adherent cells (SAC) and CD40 ligand-induced intracellular signal transduction. The absence of lymphoproliferation after fixation of SAC with paraformaldehyde has discarded the hypothesis of a superantigen-like activation. The evaluation of a cytokine pattern produced by the responding CD4(+) T lymphocytes revealed that CPSs induce a dominant Th2 pattern, with high levels of IL-4 and IL-10 production and undetectable inflammatory cytokines, such as TNF-alpha and IFN-gamma. Blockade of CD40 ligand by relevant mAb down-regulated the CPS-induced anti-inflammatory cytokine production and abolished the enhancement of fungus growth in cocultures of SAC and CD4(+) T lymphocytes. Our findings suggest that CPSs induce proliferation and differentiation of normal CD4(+) T cells into a Th2 phenotype, which could favor parasite growth and thus important deleterious effects to the host.

Publication Types:
PMID: 11698459 [PubMed - indexed for MEDLINE]