As a first #ImmunoSky post, I’m excited to share our latest pre-print, by the fantastic Mitchell Zheng!
https://www.biorxiv.org/content/10.1101/2024.12.10.627643v1.full.pdf
Our group is interested in virus-specific CD4 T cells, which means we often use in vitro stimulations (like the AIM assay) to find our cells of interest. 🧵 1/9
https://www.biorxiv.org/content/10.1101/2024.12.10.627643v1.full.pdf
Our group is interested in virus-specific CD4 T cells, which means we often use in vitro stimulations (like the AIM assay) to find our cells of interest. 🧵 1/9
Comments
Why?
Does that mean that AIM assays might be picking up cases of TCR-independent activation?
In a transwell assay, anti-CD3/CD28 stimulation can drive T cells in an adjacent chamber to express common activation markers (CD25, OX-40, 4-1BB, CD40L).
All of these responding cells had a memory phenotype, and were strongly enriched for CCR6 expression.
These same subsets are also found during standard peptide-based AIM assays.
One difference, however, appeared to be CXCR4. TCR-mediated activation efficiently downregulates CXCR4 expression, while cytokine-mediated activation has much less of an impact.
He was able to show that ag-specific CD4 cells downregulate CXCR4 while upregulating 4-1BB/CD137, giving us a more accurate way to define antigen specificity.