Role of the Innate Immune System in the Development of Hypersensitivity Pneumonitis

Abstract

Hypersensitivity pneumonitis (HP) is an extrinsic allergic alveolitis disease that is constantly affecting the farmers. It is triggered by the continuous exposure of environmental antigens, specifically antigens that grow in hot humid conditions in hay like Saccharopolyspora rectivirgula (SR). While a role of T cells has been established in the development of this diseases, the role of the innate immune system is still largely unknown in the development of lung inflammation leading to HP. To study this disease, we used a mouse model of HP, induced by SR, along with Rag−/− mice which only have an innate immune system and lack an adaptive immune system (and thus have no T cells). We hypothesized that the development of Hypersensitivity pneumonitis requires the presence of T (and B) cells, at the same time, there will be a lower percentage and number of inflammatory cells in the lungs of Rag−/− mice upon exposure to SR. WT and Rag−/− mice were exposed to SR. Lungs, spleen and lymph nodes where collected to analyze their response. We examined the percentage and number of myeloid and Innate Lymphoid Cells (ILC), as well as their ability to produce cytokines. We found that there was no significant difference in the number of Innate Lymphoid cells and myeloid cells between SR‐exposed WT and Rag−/− mice. These results may be due to the low concentration of bacteria used for these experiments. In future experiments, we propose to use a higher concentration of SR to induce inflammation. Support or Funding Information This work was supported in part by grants from the NIH‐AI38570, NIH‐AI20701, and NIH‐AI129422. NIH‐NIGMS #2R25GM096955 (RISE). VIP‐Veterinary Investigation Program.