Reduced Accumulation of Chemokine-Specific CD4 + T Cells in the Lungs of BeO- Exposed HLA-DP2 Transgenic Mice Deficient in CCL3/4 or Treated with Novel HLA- DP2/CCL-CAR-T Cells

Chemokines play an important role in the recruitment and activation of immune cells and in forming inflammatory cellular aggregates. However, how these chemokines and chemokines- specific CD4 + T cells contribute to the pathogenesis of CBD is not well defined. RNA sequencing of CD4 + T cells showed functional heterogeneity among chemokine specific- tissue-resident CCL4 tetramer-positive CD4 + T cells (CD44 + Tet + ). CD44 + Tet + cells display increased IFNγ and IL17 gene expression compared to the CD44 - Tet - (naïve) CD4 + T cells. Over-representation analysis of genes showed pathways involved in inflammation and cholesterol metabolism are significantly increased in CD44 + Tet + cells. Next, we showed that innate immune response in Be 2+ exposed HLA-DP2 Tg WT and CCL3-deficient mice (CCL3 - /- ) was not different, while a significant decrease in total, antigen-specific CD4 + T cells and IFNγ-producing CD4 + T cells was observed in CCL3 -/- mice. We also noticed fewer peribronchovascular aggregates in the lungs of Be 2+ exposed CCL3 -/- mice, suggesting reduced inflammation. In BeO-exposed lungs, enhanced CCL3 expression was observed in macrophages and dendritic cells (DCs). Further, using bone marrow chimeric mice, we established the role of hematopoietic and DCs in controlling Be-induced CCL3 and CCL4 responses in the lungs. Besides the chemokines, we also found that HLA-DP2 Tg mice deficient in TNF-α or treated with HLA-DP-CCL4-CAR-T cells show reduced presence of chemokine-specific CD4 + T cells in the lungs. In conclusion, our findings reveal an important role of DCs and TNF-α in maintaining CCL3/4-specific CD4 + T cell responses in CBD and also provide CAR-T cells as an alternative therapy for regulating CCL3/4-specific CD4 + T cell responses in CBD.