Zealous immune cells age faster
Higher-order organisms are simply trying to survive long enough for their genes to pass on. It would be evolutionary best for the immune systems to protect their host early in life. But this robustness comes at a price.
Normally, the immune response to cancer will decrease over time. This means that there will be less immune activity later on in life. However, strong immune responses can affect how the immune response to chronic cancer threats will be handled. T cells that are overactive will eventually become exhausted.
Researchers transferred tumor-specific CD8T cells to mice aged 0 to 24 years and monitored their expansion and function in response. The results showed that CD8-T cells from young hosts showed different characteristics, including increased expression of inhibitory and regulating transcription factor genes. Young tumor-infiltrating CD8 T cells developed a dysfunctional immune reaction, compared to adults.
Consider how CD8 T cells grow from nave to exhausted. A young microenvironment pushes cells further towards exhaustion, while an adults microenvironment creates a wide range of phenotypes. Ardiana Moustaki, Ph.D., St. JudeDepartment of Immunology. This work highlights how important it is to develop immunotherapies for children. Children’s immune systems are not just smaller copies of the adult. They share some of the same components, but they have different information flows, which creates a distinct equilibrium for each host.
Implications of immunotherapies
Myeloid cells inspect the body and eliminate stressed or transformed cells. These myeloid cell were found to be able to more effectively capture and present tumor antibodies in young hosts. This enabled T cells to be primed more efficiently and then eventually exhausted once they invade the tumors. The scientists analyzed immune cell samples from pediatric solid tumours. They found a relationship between exhausted CD8+T cells and the frequency PD-L1-expressing PD-L1 cells, which block immunotherapies.
Based on clinical trials and other research, it is clear that immunotherapy can prove difficult for pediatric patients in certain cases, especially in the case of solid tumors. Although there are many reasons for this, these findings suggest that children’s immune system may play a significant role. Immunotherapy will not be effective if T cells become dysfunctional from prolonged activity.
Other authors of the study are Shanta Alli and Yiping Fan, Shannon Boi and Anthony Zamora. Gang Wu, Joy Nakitandwe. Scott Newman, Scott Foy. Scott Newman, Scott Foy. Antonina Silkov. Paul Thomas. Alberto Pappo. Michael Dyer. Elizabeth Stewart. Sara Federico. St. Jude.
The National Institutes of Health (R01AI114442, UM1AI109565 and 1R01CA237311), and the National Cancer Institute (1R01AI107625, UM1AI109565 and 1R01AI136514) funded the study. Key for a Cure Foundation (P30CA021765) also funded the study. St. JudeGarwood Fellowship and St. Baldricks Foundation are the national cancer networks and ALSAC, the awareness and fundraising organization for St. Jude.