CD23 is recognized as tumor-associated antigen (TAA) in B-CLL by CD8(+) autologous T lymphocytes.

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CD23 is recognized as tumor-associated antigen (TAA) in B-CLL by CD8(+)

autologous T lymphocytes.

D Bund, C Mayr, DM Kofler, M Hallek, and CM Wendtner

Exp Hematol, June 1, 2007; 35(6): 920-30.

KKG Gene Therapy, GSF-National Research Center for Environment and Health,

Munich, Germany.

OBJECTIVE: CD23 is constitutively and atypically expressed on malignant B cells

in patients with chronic lymphocytic leukemia (B-CLL). Here, we investigated

whether CD23-derived peptides might function as B-CLL-specific tumor-associated

antigen (TAA). PATIENTS AND METHODS: Using IFN-gamma-ELISPOT assays and

HLA-A2/dimer-peptide staining we identified autologous, CD23-specific

HLA-A0201-restricted T cells after 4 weeks of in vitro culture. RESULTS: We were

able to expand autologous T cells from 8/11 B-CLL patients by using native and

CD40L-activated B-CLL cells as antigen-presenting cells (APCs) in 5 cases

whereas for 3 samples an autologous T cell response could only be evoked by use

of CD40L-stimulated B-CLL cells as APCs. The number of CD8(+) T cells could be

expanded during 4 weeks of in vitro culture with native or CD40L-activated B-CLL

cells. We could demonstrate that the expanded T cells were also able to secrete

IFN-gamma upon recognition of the antigen using IFN-gamma-ELISPOT assays.

Furthermore, these T cells not only recognized HLA-A0201-binding CD23-derived

peptides presented by T2 cells, but also CD23-overexpressing autologous B-CLL

cells in an MHC-I-restricted manner. CONCLUSION: In sum, CD23-derived peptides

were shown to be naturally processed and presented as TAA in primary B-CLL,

enabling the expansion of autologous tumor-specific T cells.

PMID: 17533046