Artículos de revistas
CD4(+) T cells downregulate Bcl-2 in germinal centers
Registro en:
Journal Of Clinical Immunology. Springer/plenum Publishers, v. 25, n. 3, n. 224, n. 229, 2005.
0271-9142
WOS:000230310600006
10.1007/s10875-005-4084-4
Autor
Schenka, AA
Muller, S
Fournie, JJ
Capila, F
Vassallo, J
Delsol, G
Valitutti, S
Brousset, P
Institución
Resumen
Germinal centers (GCs) are the main site of T cell-dependent antibody responses. Upon antigen challenge, GCs comprise mostly B cells undergoing proliferation, somatic hypermutation and antigen-affinity selection. GC B cells down-modulate the expression of Bcl-2 protein and are highly sensitive to apoptosis to eliminate autoreactive or low-affinity cells. Bcl-2 is still expressed in a few GC cells, whose identity remains unclear. To address this issue, we examined by confocal microscopy the expression of Bcl-2 by different GC lymphocyte subsets in hyperplastic tonsils. We found that the vast majority of Bcl-2(+) GC cells are T lymphocytes. Conversely, while in the mantle zone and in the interfollicular areas T cells are almost exclusively Bcl-2+, in the GC, most T lymphocytes are Bcl-2(-). In addition, most of the CD4(+) GC T cells are Bcl-2-, while nearly 100% of the CD8(+) GC T cells are Bcl-2(+). The Bcl-2 downregulation by both B and CD4(+) T GC cells supports the concept that these two subsets may undergo a selection process in this microenvironment. 25 3 224 229