Efficient gene deletion of Integrin alpha 4 in primary mouse CD4 T cells using CRISPR RNA pair-mediated fragmentation

The functional specialization of CD4 T lymphocytes into various subtypes, including T_H1 and T_FH cells, is crucial for effective immune responses. T_FH cells facilitate B cell differentiation within germinal centers, while T_H1 cells are vital for cell-mediated immunity against intracellular pathogens. Integrin α4, a cell surface adhesion molecule, plays significant roles in cell migration and co-stimulatory signaling. In this study, we investigated the role of Integrin α4 in regulating T_FH and T_H1 cell populations during acute viral infection using CRISPR-Cas9 gene editing. To effectively delete the <i>Itga4</i> in primary mouse CD4 T cells, we selected various combinations of crRNAs and generated ribonucleoprotein complexes with fluorochrome-conjugated tracrRNAs and Cas9 proteins. These crRNA pairs enhanced gene deletion by generating deletions in the gene. By analyzing the effects of <i>Itga4</i> deficiency on T_FH and T_H1 cell differentiation during acute LCMV infection, we found that optimized crRNA pairs significantly increased the T_H1 cell population. Our results highlight the importance of selecting and combining appropriate crRNAs for effective CRISPR-Cas9 gene editing in primary CD4 T cells. Additionally, our study demonstrates the role of Integrin α4 in regulating the differentiation of CD4 T cells, suggesting the potential molecular mechanisms driving T cell subset differentiation through integrin targeting.