What is the difference between cell engagers and bispecific antibodies?5 answersBispecific antibodies and cell engagers are both innovative immunotherapies with distinct mechanisms of action. Bispecific antibodies, as demonstrated in Context_1 and Context_4, are designed to simultaneously bind to two different targets, such as tumor antigens and immune cells, activating effector mechanisms like complement-dependent cytotoxicity or T cell-mediated killing. On the other hand, cell engagers, exemplified in Context_2 and Context_3, specifically recruit immune cells like T cells or NK cells to target tumor cells, inducing cell activation and tumor cell lysis. While bispecific antibodies can activate complement systems and have versatile applications, cell engagers, particularly NK-cell engagers, are highlighted for their safer profile and effectiveness in reducing proinflammatory cytokine production. Overall, the key distinction lies in the direct targeting of immune cells by cell engagers versus the dual binding capacity of bispecific antibodies to engage both immune cells and tumor cells simultaneously.
How does PD-L1 contribute to prognosis in hematological malignancies?5 answersPD-L1 expression plays a crucial role in predicting prognosis in various hematological malignancies. In multiple myeloma (MM), high PD-L1 expression is linked to poor overall survival (OS) and progression-free survival, especially in patients not undergoing autologous stem cell transplantation (ASCT). In acute myeloid leukemia (AML), high levels of the PD-L1 transcription variant v1/v2 are associated with worse OS, particularly in AML subgroups with specific genetic mutations. Additionally, PD-L1 expression in extranodal natural killer/T-cell lymphoma (ENKTL) serves as an independent predictor of poor prognosis, with lower expression levels correlating with a higher risk of relapse and refractoriness. Overall, PD-L1 expression in hematological malignancies like diffuse large B-cell lymphoma (DLBCL) is indicative of poor OS and adverse clinicopathological features, emphasizing its significance as a prognostic biomarker.
Is death receptor signaling involved in the drug efficacy of CD3 bispecific antibodies?5 answersDeath receptor signaling is not directly mentioned in the provided contexts regarding the drug efficacy of CD3 bispecific antibodies. However, the contexts highlight crucial factors influencing the efficacy of CD3 bispecific antibodies. Studies reveal that CD8+ T cells rely on CD4+ T cell-derived signaling factors for sustained killing in vitro. Additionally, resistance mechanisms to CD3-bispecific antibodies involve IFNγ signaling and core fucosylation pathways, impacting the therapeutic response. These findings emphasize the intricate interplay of various signaling pathways and molecular mechanisms in modulating the effectiveness of CD3 bispecific antibodies, shedding light on potential targets for enhancing their clinical potential.
How CD3 cause T cell exhaution through PD-L1 expression and PD-1 checkpoint pathway in cancer?5 answersCD8 positive lymphocytes expressing CD3 can lead to T cell exhaustion through the PD-L1 expression and PD-1 checkpoint pathway in cancer. PD-L1, synthesized in the endoplasmic reticulum, interacts with PD-1 on T cells, delivering coinhibitory signals that suppress T cell function, aiding in immune evasion by tumor cells. PD-L1 expression is found in various human tumor types and correlates with the presence of intratumoral CD8 positive lymphocytes, suggesting that the antitumor immune response may induce tumoral PD-L1 expression. In fibroblastic tumors, the expression of PD-L1 and PD-1 is limited, but TIM3 is widely expressed, with high TIM3 levels correlating with TIL density, indicating a potential role in immunosuppression. Therefore, targeting PD-1/PD-L1 and TIM3 in fibroblastic tumors with high expression levels may benefit patients through combination therapy.
What are the potential drawbacks of using PD-L1 in the treatment of melanoma?5 answersPD-L1 expression in melanoma has been used as a potential biomarker for predicting response to immune checkpoint blockade (ICB) therapy. However, there are potential drawbacks associated with using PD-L1 in the treatment of melanoma. One drawback is that PD-L1 expression is not consistently correlated with clinical outcomes in melanoma patients treated with ICB therapy. Another drawback is the heterogeneity of PD-L1 expression within tumors, which can lead to discordant results and challenges in accurately assessing PD-L1 status. Additionally, the use of different PD-L1 antibodies in immunohistochemistry assays can result in variations in staining properties, further complicating the interpretation of PD-L1 expression. These drawbacks highlight the need for further research and refinement in the use of PD-L1 as a biomarker in melanoma treatment.
Is TCR-T cell therapy generally safe?3 answersTCR-T cell therapy has shown promise as a treatment for cancer patients, but safety concerns remain. While some TCRs possess cross-reactivity to unrelated MHC molecules, TCR chain centricity can be exploited to enhance desired antitumor TCR reactivity and eliminate unwanted TCR cross-reactivity. Personalized TCR-T cell therapy, using TCRs from naturally occurring tumor antigen-specific T cells, has shown therapeutic effects on autologous patient-derived xenograft tumors. TCR-engineered cellular therapy targeting tumor-specific neoantigens has demonstrated significant antitumor effects in preclinical models. Further fine-tuning is necessary to improve functionality and safety for the treatment of solid tumors. The AFNT-111 cell therapy, targeting the KRAS G12V mutation, aims to limit tumor escape and promote increased T cell activity and persistence. While these studies show promising results, careful monitoring for possible harmful toxicities caused by adoptive transfer of T cells redirected by TCRs is still mandatory.