RESUMO
To obtain a better understanding of the biology behind life-threatening fungal infections caused by Candida albicans, we recently conducted an in silico screening for fungal and host protein interaction partners. We report here that the extracellular domain of human CD4 binds to the moonlighting protein enolase 1 (Eno1) of C. albicans as predicted bioinformatically. By using different anti-CD4 monoclonal antibodies, we determined that C. albicans Eno1 (CaEno1) primarily binds to the extracellular domain 3 of CD4. Functionally, we observed that CaEno1 binding to CD4 activated lymphocyte-specific protein tyrosine kinase (LCK), which was also the case for anti-CD4 monoclonal antibodies tested in parallel. CaEno1 binding to naïve human CD4+ T cells skewed cytokine secretion toward a Th2 profile indicative of poor fungal control. Moreover, CaEno1 inhibited human memory CD4+ T-cell recall responses. Therapeutically, CD4+ T cells transduced with a p41/Crf1-specific T-cell receptor developed for adoptive T-cell therapy were not inhibited by CaEno1 in vitro. Together, the interaction of human CD4+ T cells with CaEno1 modulated host CD4+ T-cell responses in favor of the fungus. Thus, CaEno1 mediates not only immune evasion through its interference with complement regulators but also through the direct modulation of CD4+ T-cell responses.
Assuntos
Candida albicans , Linfócitos T , Humanos , Linfócitos T/metabolismo , Linfócitos T CD4-Positivos , Fosfopiruvato Hidratase/metabolismo , Anticorpos Monoclonais/metabolismoRESUMO
BACKGROUND: Hosts are able to restrict viral replication to contain virus spread before adaptive immunity is fully initiated. Many viruses have acquired genes directly counteracting intrinsic restriction mechanisms. This phenomenon has led to a co-evolutionary signature for both the virus and host which often provides a barrier against interspecies transmission events. Through different mechanisms of action, but with similar consequences, spumaviral feline foamy virus (FFV) Bet and lentiviral feline immunodeficiency virus (FIV) Vif counteract feline APOBEC3 (feA3) restriction factors that lead to hypermutation and degradation of retroviral DNA genomes. Here we examine the capacity of vif to substitute for bet function in a chimeric FFV to assess the transferability of anti-feA3 factors to allow viral replication. RESULTS: We show that vif can replace bet to yield replication-competent chimeric foamy viruses. An in vitro selection screen revealed that an engineered Bet-Vif fusion protein yields suboptimal protection against feA3. After multiple passages through feA3-expressing cells, however, variants with optimized replication competence emerged. In these variants, Vif was expressed independently from an N-terminal Bet moiety and was stably maintained. Experimental infection of immunocompetent domestic cats with one of the functional chimeras resulted in seroconversion against the FFV backbone and the heterologous FIV Vif protein, but virus could not be detected unambiguously by PCR. Inoculation with chimeric virus followed by wild-type FFV revealed that repeated administration of FVs allowed superinfections with enhanced antiviral antibody production and detection of low level viral genomes, indicating that chimeric virus did not induce protective immunity against wild-type FFV. CONCLUSIONS: Unrelated viral antagonists of feA3 cellular restriction factors can be exchanged in FFV, resulting in replication competence in vitro that was attenuated in vivo. Bet therefore may have additional functions other than A3 antagonism that are essential for successful in vivo replication. Immune reactivity was mounted against the heterologous Vif protein. We conclude that Vif-expressing FV vaccine vectors may be an attractive tool to prevent or modulate lentivirus infections with the potential option to induce immunity against additional lentivirus antigens.
Assuntos
Produtos do Gene vif/genética , Vírus da Imunodeficiência Felina/genética , Proteínas dos Retroviridae/genética , Spumavirus/genética , Vacinas Virais/genética , Replicação Viral , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Gatos , Linhagem Celular , Citidina Desaminase/genética , Citidina Desaminase/metabolismo , Ordem dos Genes , Produtos do Gene gag/metabolismo , Genoma Viral , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Vírus da Imunodeficiência Felina/imunologia , Recombinação Genética , Infecções por Retroviridae/genética , Infecções por Retroviridae/metabolismo , Infecções por Retroviridae/virologia , Spumavirus/imunologia , Carga Viral , Vacinas Virais/imunologiaRESUMO
The functional fitness of CAR T cells plays a crucial role in determining their clinical efficacy. Several strategies are being explored to increase cellular fitness, but screening these approaches in vivo is expensive and time-consuming, limiting the number of strategies that can be tested at one time. The presence of polyfunctional CAR T cells has emerged as a critical parameter correlating with clinical responses. However, even sophisticated multiplexed secretomic assays often fail to detect differences in cytokine release due to the functional heterogeneity of CAR T cell products. Here, we describe a highly multiplexed single-cell secretomic assay based on the IsoLight platform to rapidly evaluate the impact of new pharmacologic or gene-engineering approaches aiming at improving CAR T cell function. As a key study, we focus on CD19-specific CAR CD8+ T cells modulated by miR-155 overexpression, but the protocol can be applied to characterize other functional immune cell modulation strategies.
Assuntos
Linfócitos T CD8-Positivos , Receptores de Antígenos de Linfócitos T , Resultado do Tratamento , Antígenos CD19 , Imunoterapia Adotiva/métodosRESUMO
High frequencies of stem-like memory T cells in infusion products correlate with superior patient outcomes across multiple T cell therapy trials. Herein, we analyzed a published CRISPR activation screening to identify transcriptional regulators that could be harnessed to augment stem-like behavior in CD8+ T cells. Using IFN-γ production as a proxy for CD8+ T cell terminal differentiation, LMO4 emerged among the top hits inhibiting the development of effectors cells. Consistently, we found that Lmo4 was downregulated upon CD8+ T cell activation but maintained under culture conditions facilitating the formation of stem-like T cells. By employing a synthetic biology approach to ectopically express LMO4 in antitumor CD8+ T cells, we enabled selective expansion and enhanced persistence of transduced cells, while limiting their terminal differentiation and senescence. LMO4 overexpression promoted transcriptional programs regulating stemness, increasing the numbers of stem-like CD8+ memory T cells and enhancing their polyfunctionality and recall capacity. When tested in syngeneic and xenograft tumor models, LMO4 overexpression boosted CD8+ T cell antitumor immunity, resulting in enhanced tumor regression. Rather than directly modulating gene transcription, LMO4 bound to JAK1 and potentiated STAT3 signaling in response to IL-21, inducing the expression of target genes (Tcf7, Socs3, Junb, and Zfp36) crucial for memory responses. CRISPR/Cas9-deletion of Stat3 nullified the enhanced memory signature conferred by LMO4, thereby abrogating the therapeutic benefit of LMO4 overexpression. These results establish LMO4 overexpression as an effective strategy to boost CD8+ T cell stemness, providing a new synthetic biology tool to bolster the efficacy of T cell-based immunotherapies.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Linfócitos T CD8-Positivos , Proteínas com Domínio LIM , Fator de Transcrição STAT3 , Transdução de Sinais , Proteínas com Domínio LIM/genética , Proteínas com Domínio LIM/imunologia , Linfócitos T CD8-Positivos/imunologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Fator de Transcrição STAT3/metabolismo , Camundongos , Animais , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Humanos , Transdução de Sinais/imunologia , Transdução de Sinais/genética , Interleucinas/genética , Interleucinas/imunologia , Diferenciação Celular/genética , Diferenciação Celular/imunologiaAssuntos
Imunoterapia , Nanofios , Linfócitos T , Humanos , Nanofios/química , Imunoterapia/métodos , Linfócitos T/imunologia , Animais , CamundongosRESUMO
Defined host-encoded feline APOBEC3 (feA3) cytidine deaminases efficiently restrict the replication and spread of exogenous retroviruses like Feline Immunodeficiency Virus (FIV) and Feline Foamy Virus (FFV) which developed different feA3 counter-acting strategies. Here we characterize the molecular interaction of FFV proteins with the diverse feA3 proteins. The FFV accessory protein Bet is the virus-encoded defense factor which is shown here to bind all feA3 proteins independent of whether they restrict FFV, a feature shared with FIV Vif that induces degradation of all feA3s including those that do not inactivate FIV. In contrast, only some feA3 proteins bind to FFV Gag, a pattern that in part reflects the restriction pattern detected. Additionally, one-domain feA3 proteins can homo- and hetero-dimerize in vitro, but a trans-dominant phenotype of any of the low-activity feA3 forms on FFV restriction by one of the highly-active feA3Z2 proteins was not detectable.