| Affiliation: | 1.Laboratory of Immunopathology, Department of Experimental Therapy, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy,Polish Academy of Sciences,Wroc?aw,Poland;2.Department and Clinic of Haematology, Blood Neoplasms, and Bone Marrow Transplantation,Wroclaw Medical University,Wroc?aw,Poland |
| Abstract: | Previously, we showed that cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) is overexpressed in chronic lymphocytic leukaemia (CLL) and its expression is correlated with the expression of the major regulators of G1 phase progression: cyclins D2 and D3, and cyclin-dependent kinase inhibitory protein 1 (p27 KIP1 ). In the present study, we blocked CTLA-4 on the surface of both CLL cells and normal B lymphocytes to investigate the impact of CTLA-4 on the expression of the mentioned G1 phase regulators. We found that in CLL patients and in healthy individuals, the median proportions of cyclin D2-positive cells as well as cyclin D3+ cells significantly decreased following CTLA-4 blockade. Moreover, CTLA-4 blockade led to an increase in the median frequencies of p27 KIP1 -positive cells, although this increase was marked only in CLL patients. Our study showed that CTLA-4 affects the expression of the key regulators of G1 phase progression in CLL cells as well as in normal B lymphocytes and may contribute to a better understanding of the role of CTLA-4 in the regulation of G1 phase progression. |
