RESUMO
Aberrant immune synapse formation between antigen-presenting and immune effector cells is a central mediator of immune dysfunction and can be observed across several haematologic malignancies. Here, we describe the cell preparation, conjugation and immune synapse quantification of B and T cells obtained from patients with leukaemia and the adaptions required when using cells from murine models of disease.
Assuntos
Células Apresentadoras de Antígenos/imunologia , Linfócitos B/imunologia , Sinapses Imunológicas/imunologia , Leucemia/imunologia , Linfócitos T/imunologia , Animais , Células Apresentadoras de Antígenos/patologia , Linfócitos B/patologia , Linhagem Celular Tumoral , Humanos , Sinapses Imunológicas/patologia , Leucemia/patologia , Camundongos , Linfócitos T/patologiaRESUMO
Mutated mitogen-activated protein kinase (MAPK) pathway components promote tumor survival, proliferation, and immune evasion in solid tumors. MAPK mutations occur in hematologic cancers as well, but their role is less clear and few models are available to study this. We developed an in vivo model of disseminated BRAFV600E B-cell leukemia to determine the effects of this mutation on tumor development and immune evasion. Mice with B-cell-restricted BRAFV600E expression crossed with the Eµ-TCL1 model of chronic lymphocytic leukemia (CLL) developed leukemia significantly earlier (median, 4.9 vs 8.1 months; P < .001) and had significantly shorter lifespan (median, 7.3 vs 12.1 months; P < .001) versus BRAF wild-type counterparts. BRAFV600E expression did not affect B-cell proliferation but reduced spontaneous apoptosis. BRAFV600E-mutant leukemia produced greater T-cell effects, evidenced by exhaustion immunophenotype and CD44+ T-cell percentage, as well as increased expression of PD-L1 on CD11b+ cells. Results were confirmed in syngeneic mice engrafted with BRAFV600E leukemia cells. Furthermore, a BRAFV600E-expressing CLL cell line more strongly inhibited anti-CD3/CD28-induced T-cell proliferation, which was reversed by BRAFV600E inhibition. These results demonstrate the immune-suppressive impact of BRAFV600E in B-cell leukemias and introduce a new model to develop rational combination strategies targeting both tumor cells and tumor-mediated immune evasion.
