RESUMEN
Neonatal and infant immune responses are characterized by a limited capability to generate protective Ab titers and memory B cells as seen in adults. Multiple studies support an immature or even impaired character of umbilical cord blood (UCB) B cells themselves. In this study, we provide a comprehensive molecular and functional comparison of B cell subsets from UCB and adult peripheral blood. Most UCB B cells have a mature, naive B cell phenotype as seen in adults. The UCB Ig repertoire is highly variable but interindividually conserved, as BCR clonotypes are frequently shared between neonates. Furthermore, UCB B cells show a distinct transcriptional program that confers accelerated responsiveness to stimulation and facilitated IgA class switching. Stimulation drives extensive differentiation into Ab-secreting cells, presumably limiting memory B cell formation. Humanized mice suggest that the distinctness of UCB versus adult B cells is already reflected by the developmental program of hematopoietic precursors, arguing for a layered B-1/B-2 lineage system as in mice, albeit our findings suggest only partial comparability to murine B-1 cells. Our study shows that UCB B cells are not immature or impaired but differ from their adult mature counterpart in a conserved BCR repertoire, efficient IgA class switching, and accelerated, likely transient response dynamics.
Asunto(s)
Linfocitos B/inmunología , Sangre Fetal/inmunología , Inmunoglobulinas/inmunología , Animales , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Ratones , Ratones Congénicos , Ratones Endogámicos NOD , Receptores de Antígenos de Linfocitos B/inmunologíaRESUMEN
In this work, we are reporting that "Shock and Kill", a therapeutic approach designed to eliminate latent HIV from cell reservoirs, is extrapolatable to cancer therapy. This is based on the observation that malignant cells express a spectrum of human endogenous retroviral elements (HERVs) which can be transcriptionally boosted by HDAC inhibitors. The endoretroviral gene HERV-V2 codes for an envelope protein, which resembles syncytins. It is significantly overexpressed upon exposure to HDAC inhibitors and can be effectively targeted by simultaneous application of TLR7/8 agonists, triggering intrinsic apoptosis. We demonstrated that this synergistic cytotoxic effect was accompanied by the functional disruption of the TLR7/8-NFκB, Akt/PKB, and Ras-MEK-ERK signalling pathways. CRISPR/Cas9 ablation of TLR7 and HERV-V1/V2 curtailed apoptosis significantly, proving the pivotal role of these elements in driving cell death. The effectiveness of this new approach was confirmed in ovarian tumour xenograft studies, revealing a promising avenue for future cancer therapies.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Retrovirus Endógenos/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Neoplasias Ováricas/tratamiento farmacológico , Receptor Toll-Like 7/agonistas , Activación Viral/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Depsipéptidos/farmacología , Retrovirus Endógenos/genética , Retrovirus Endógenos/metabolismo , Femenino , Humanos , Imiquimod/farmacología , Inmunidad Innata/efectos de los fármacos , Ratones Desnudos , Neoplasias Ováricas/inmunología , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/virología , Pteridinas/farmacología , Transducción de Señal , Receptor Toll-Like 7/genética , Receptor Toll-Like 7/metabolismo , Células Tumorales Cultivadas , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/metabolismo , Vorinostat/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Human memory B cells (MBCs) are generated and diversified in secondary lymphoid tissues throughout the organism. A paired immunoglobulin (Ig)-gene repertoire analysis of peripheral blood (PB) and splenic MBCs from infant, adult, and elderly humans revealed that throughout life, circulating MBCs are comprehensively archived in the spleen. Archive MBC clones are systematically preserved and uncoupled from class-switching. Clonality in the spleen increases steadily, but boosts at midlife, thereby outcompeting small clones. The splenic marginal zone (sMZ) represents a primed MBC compartment, generated from a stochastic exchange within the archive memory pool. This is supported by functional assays, showing that PB and splenic CD21+ MBCs acquire transient CD21high expression upon NOTCH2-stimulation. Our study provides insight that the human MBC system in PB and spleen is composed of three interwoven compartments: the dynamic relationship of circulating, archive, and its subset of primed (sMZ) memory changes with age, thereby contributing to immune aging.