RESUMO
Classic major histocompatibility complex class I (MHC-I) presentation relies on shuttling cytosolic peptides into the endoplasmic reticulum (ER) by the transporter associated with antigen processing (TAP). Viruses disable TAP to block MHC-I presentation and evade cytotoxic CD8+ T cells. Priming CD8+ T cells against these viruses is thought to rely solely on cross-presentation by uninfected TAP-functional dendritic cells. We found that protective CD8+ T cells could be mobilized during viral infection even when TAP was absent in all hematopoietic cells. TAP blockade depleted the endosomal recycling compartment of MHC-I molecules and, as such, impaired Toll-like receptor-regulated cross-presentation. Instead, MHC-I molecules accumulated in the ER-Golgi intermediate compartment (ERGIC), sequestered away from Toll-like receptor control, and coopted ER-SNARE Sec22b-mediated vesicular traffic to intersect with internalized antigen and rescue cross-presentation. Thus, when classic MHC-I presentation and endosomal recycling compartment-dependent cross-presentation are impaired in dendritic cells, cell-autonomous noncanonical cross-presentation relying on ERGIC-derived MHC-I counters TAP dysfunction to nevertheless mediate CD8+ T cell priming.
Assuntos
Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Linfócitos T CD8-Positivos/imunologia , Apresentação Cruzada , Células Dendríticas/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Vírus da Influenza A/imunologia , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/virologia , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/virologia , Proliferação de Células , Células Cultivadas , Técnicas de Cocultura , Células Dendríticas/metabolismo , Células Dendríticas/virologia , Modelos Animais de Doenças , Retículo Endoplasmático/imunologia , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/virologia , Feminino , Complexo de Golgi/imunologia , Complexo de Golgi/metabolismo , Complexo de Golgi/virologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Interações Hospedeiro-Patógeno , Humanos , Vírus da Influenza A/patogenicidade , Ativação Linfocitária , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/genéticaRESUMO
Redirecting T cells to specifically kill malignant cells has been validated as an effective anti-cancer strategy in the clinic with the approval of blinatumomab for acute lymphoblastic leukemia. However, the immunosuppressive nature of the tumor microenvironment potentially poses a significant hurdle to T cell therapies. In hematological malignancies, the bone marrow (BM) niche is protective to leukemic stem cells and has minimized the efficacy of several anti-cancer drugs. In this study, we investigated the impact of the BM microenvironment on T cell redirection. Using bispecific antibodies targeting specific tumor antigens (CD123 and BCMA) and CD3, we observed that co-culture of acute myeloid leukemia or multiple myeloma cells with BM stromal cells protected tumor cells from bispecific antibody-T cell-mediated lysis in vitro and in vivo. Impaired CD3 redirection cytotoxicity was correlated with reduced T cell effector responses and cell-cell contact with stromal cells was implicated in reducing T cell activation and conferring protection of cancer cells. Finally, blocking the VLA4 adhesion pathway in combination with CD3 redirection reduced the stromal-mediated inhibition of cytotoxicity and T cell activation. Our results lend support to inhibiting VLA4 interactions along with administering CD3 redirection therapeutics as a novel combinatorial regimen for robust anti-cancer responses.
Assuntos
Antineoplásicos Imunológicos/farmacologia , Medula Óssea/efeitos dos fármacos , Complexo CD3/imunologia , Integrina alfa4beta1/antagonistas & inibidores , Leucemia Mieloide Aguda/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Animais , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Antígeno de Maturação de Linfócitos B/antagonistas & inibidores , Antígeno de Maturação de Linfócitos B/imunologia , Medula Óssea/imunologia , Medula Óssea/patologia , Complexo CD3/antagonistas & inibidores , Linhagem Celular Tumoral , Feminino , Humanos , Integrina alfa4beta1/imunologia , Subunidade alfa de Receptor de Interleucina-3/antagonistas & inibidores , Subunidade alfa de Receptor de Interleucina-3/imunologia , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/patologia , Camundongos , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/patologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/patologia , Microambiente Tumoral/efeitos dos fármacosRESUMO
CD33 is expressed in 90% of patients with acute myeloid leukemia (AML), and its extracellular portion consists of a V domain and a C2 domain. A recent study showed that a single nucleotide polymorphism (SNP), rs12459419 (C > T), results in the reduced expression of V domain-containing CD33 and limited efficacy of V domain-binding anti-CD33 antibodies. We developed JNJ-67571244, a novel human bispecific antibody capable of binding to the C2 domain of CD33 and to CD3, to induce T-cell recruitment and CD33+ tumor cell cytotoxicity independently of their SNP genotype status. JNJ-67571244 specifically binds to CD33-expressing target cells and induces cytotoxicity of CD33+ AML cell lines in vitro along with T-cell activation and cytokine release. JNJ-67571244 also exhibited statistically significant antitumor activity in vivo in established disseminated and subcutaneous mouse models of human AML. Furthermore, this antibody depletes CD33+ blasts in AML patient blood samples with concurrent T-cell activation. JNJ-67571244 also cross-reacts with cynomolgus monkey CD33 and CD3, and dosing of JNJ-67571244 in cynomolgus monkeys resulted in T-cell activation, transient cytokine release, and sustained reduction in CD33+ leukocyte populations. JNJ-67571244 was well tolerated in cynomolgus monkeys up to 30 mg/kg. Lastly, JNJ-67571244 mediated efficient cytotoxicity of cell lines and primary samples regardless of their SNP genotype status, suggesting a potential therapeutic benefit over other V-binding antibodies. JNJ-67571244 is currently in phase 1 clinical trials in patients with relapsed/refractory AML and high-risk myelodysplastic syndrome.
Assuntos
Leucemia Mieloide Aguda , Linfócitos T , Animais , Domínios C2 , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Macaca fascicularis , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/genética , Linfócitos T/metabolismoRESUMO
Adaptation of the endoplasmic reticulum (ER) pathway for MHC class I (MHC-I) presentation in dendritic cells enables cross-presentation of peptides derived from phagocytosed microbes, infected cells, or tumor cells to CD8 T cells. How these peptides intersect with MHC-I molecules remains poorly understood. Here, we show that MHC-I selectively accumulate within phagosomes carrying microbial components, which engage Toll-like receptor (TLR) signaling. Although cross-presentation requires Sec22b-mediated phagosomal recruitment of the peptide loading complex from the ER-Golgi intermediate compartment (ERGIC), this step is independent of TLR signaling and does not deliver MHC-I. Instead, MHC-I are recruited from an endosomal recycling compartment (ERC), which is marked by Rab11a, VAMP3/cellubrevin, and VAMP8/endobrevin and holds large reserves of MHC-I. While Rab11a activity stocks ERC stores with MHC-I, MyD88-dependent TLR signals drive IκB-kinase (IKK)2-mediated phosphorylation of phagosome-associated SNAP23. Phospho-SNAP23 stabilizes SNARE complexes orchestrating ERC-phagosome fusion, enrichment of phagosomes with ERC-derived MHC-I, and subsequent cross-presentation during infection.