RESUMO
CpG oligodeoxynucleotides (CpG) and IL-21 are two promising agents for the treatment of B-cell chronic lymphocytic leukemia (B-CLL). Recently, we reported that the combination of CpG and IL-21 (CpG/IL-21) can induce granzyme B (GrB)-dependent apoptosis in B-CLL cells. Here, we demonstrate that treatment of B-CLL cells with CpG and IL-21 results in the development of antigen-presenting cell (APC)-like cells with cytotoxic features. These properties eventually give rise to B-CLL cell apoptosis, independently of their cytogenetic phenotype, whereas normal B-cell survival is not negatively affected by CpG/IL-21. APC- and CTL-typical molecules found to be up-regulated in CpG/IL-21-stimulated B-CLL cells include GrB, perforin, T-bet, monokine-induced by IFN-γ and IFN-γ-inducible protein 10 (IP-10), as well as molecules important for cell adhesion, antigen cross-presentation and costimulation. Also induced are molecules involved in GrB induction, trafficking and processing, whereas the GrB inhibitor Serpin B9 [formerly proteinase inhibitor-9 (PI-9)] is down-modulated by CpG/IL-21. In conclusion, CpG/IL-21-stimulated B-CLL cells acquire features that are reminiscent of killer dendritic cells, and which result in enhanced immunogenicity, cytotoxicity and apoptosis. Our results provide novel insights into the aberrant immune state of B-CLL cells and may establish a basis for the development of an innovative cellular vaccination approach in B-CLL.
Assuntos
Células Apresentadoras de Antígenos/efeitos dos fármacos , Linfócitos B/efeitos dos fármacos , Interleucinas/farmacologia , Leucemia Linfocítica Crônica de Células B/imunologia , Ativação Linfocitária/efeitos dos fármacos , Oligodesoxirribonucleotídeos/farmacologia , Idoso , Idoso de 80 Anos ou mais , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/patologia , Apoptose/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/patologia , Quimiocina CXCL10/genética , Quimiocina CXCL10/imunologia , Citotoxicidade Imunológica/efeitos dos fármacos , Feminino , Regulação Leucêmica da Expressão Gênica , Granzimas/genética , Granzimas/imunologia , Humanos , Imunofenotipagem , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Pessoa de Meia-Idade , Perforina/genética , Perforina/imunologia , Cultura Primária de Células , Proteínas Recombinantes/farmacologia , Transdução de Sinais , Proteínas com Domínio T/genética , Proteínas com Domínio T/imunologiaRESUMO
Recently, we reported that IL-21 induces granzyme B (GzmB) and GzmB-dependent apoptosis in malignant CD5(+) B cells from patients with chronic lymphocytic leukemia. Several autoimmune diseases (AD) are associated with enhanced frequencies of CD5(+) B cells. Since AD are also associated with elevated IL-21 and GzmB levels, we postulated a link between CD5(+) B cells, IL-21 and GzmB. Here, we demonstrate that IL-21 and GzmB serum levels are highly correlated in subjects with systemic lupus erythematosus (SLE) and that freshly isolated CD5(+) SLE B cells constitutively express GzmB. IL-21 directly induced GzmB expression and secretion by CD5(+) B cells from several AD and from cord blood in vitro, and the simultaneous presence of BCR stimulation strongly enhanced this process. Furthermore, IL-21 suppressed both viability and expansion of CD5(+) B cells from SLE individuals. In summary, our study may explain the elevated levels of IL-21 and GzmB in SLE and other AD. Moreover, our data suggest that IL-21 may have disease-modifying characteristics by inducing GzmB in CD5(+) B cells and by suppressing their expansion. Our results provide the rationale for further evaluation of the therapeutic potential of IL-21 in certain AD such as SLE.
Assuntos
Linfócitos B/metabolismo , Granzimas/metabolismo , Interleucinas/biossíntese , Lúpus Eritematoso Sistêmico/imunologia , Receptores de Antígenos de Linfócitos B/metabolismo , Adolescente , Adulto , Idoso , Linfócitos B/imunologia , Linfócitos B/patologia , Antígenos CD5/biossíntese , Proliferação de Células , Sobrevivência Celular/imunologia , Feminino , Granzimas/genética , Humanos , Tolerância Imunológica , Interleucinas/sangue , Interleucinas/genética , Interleucinas/imunologia , Lúpus Eritematoso Sistêmico/sangue , Masculino , Pessoa de Meia-Idade , Receptor Cross-Talk/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Interleucina-21/biossíntese , Receptores de Interleucina-21/genéticaRESUMO
Human B cells are currently not known to produce the proapoptotic protease granzyme B (GrB) in physiological settings. We have discovered that BCR stimulation with either viral Ags or activating Abs in the context of the acute phase cytokine IL-21 can induce the secretion of substantial amounts of GrB by human B cells. Importantly, GrB response to viral Ags was significantly stronger in B cells from subjects recently vaccinated against the corresponding viruses as compared with unvaccinated subjects. GrB-secreting B cells featured a homogeneous CD19(+)CD20(+)CD27(-)CD38(-)IgD(-) phenotype, improved survival, and enhanced expression of costimulatory, Ag-presenting and cell-adhesion molecules. B cell-derived GrB was enzymatically active and its induction required the activation of similar signaling pathways as those in CTLs. Our findings suggest that GrB-secreting B cells support the early antiviral immune response against viruses with endosomal entry pathways, thereby counteracting overwhelming viral replication at the beginning of an infection until virus-specific T cells from draining lymph nodes arrive at the site of infection. Our data may also explain the elevated serum GrB levels found in the early phase of various viral diseases.