 is Dr. Shilpa Kodadi. And then she is a graduate of the Imperial College in London and is currently doing an observorship here. And she is a post-doctoral research fellow at Harvard Medical School. And she's going to be talking about dry ice. Good morning, everyone. I'm going to be talking about one of my projects that I've been working on at Boston. And that's looking at the chemokine mediated mechanisms of antigen presenting cell trafficking in dry eye disease. So why do we care about dry eye disease? Dry eye disease is a highly prevalent condition affecting estimated 10 million Americans. It's one of the most common causes for patients seeking ophthalmic care and has a significant financial burden to the health care system. So this is a model of the immunopathogenesis of dry eye disease taken from a paper by the Steve Flugfelder and Michael Stern group in which they propose that desiccating stress and increased tear film osmolarity leads to activation of the epithelial stress pathway. And that this results in the production of inflammatory cytokines, which lead to the recruitment of antigen presenting cells to the ocular surface and their subsequent activation and migration to regional lymph nodes. Once they get to the regional lymph nodes, they subsequently activate or prime T cells, which then home to the ocular surface and mediate pathology causing dry eye disease. So we've been looking at the afferent arm of this immune response, looking at APC recruitment to the ocular surface and the dynamics of homing to regional lymph nodes. So the cornea contains several different populations of antigen presenting cells. The CD11C population, which are a population of dendritic cells within the epithelium and the CD11B population, where CD11B is a macrophage marker. And this population exists within the stroma. And we've been studying the second population, the CD11B population, of the stroma. Chemokines are small molecular weight cytokines. And they have chemo-tracing properties. And they have a critical role in regulating the migration and activation of immune cells. And to date, there is limited data on the role of chemokines in dry eye disease. So we hypothesized that desiccating stress would lead to an up-regulation of chemokine receptor expression by antigen presenting cells and an increase in the expression of their respective chemokine ligands on the ocular surface, which will lead to an ingress of APCs and their subsequent homing to lymphoid tissues. So we've been looking at these four chemokine receptors. Now, CCR1, 2, and 5 are expressed by immature antigen presenting cells responsible for mediating trafficking of antigen presenting cells to sites of inflammation. And CCR7 is expressed on mature APCs. And they're responsible for facilitating trafficking to lymph nodes. So the lab has developed a validated model of dry eye disease where we take naive mice and replace them in a controlled environment chamber. And we regulate environmental factors such as humidity, temperature, and airflow. And secondly, we also inject them with an anti-moscarinic drug, scopolamine, to further dry aqueous secretions. And during this time period, we check the clinical fluorescence staining score at regular intervals to confirm the induction and the maintenance of dry eye disease. So the first thing that we did is we looked at the numbers of CD11B cells infiltrating the corneal stroma. And we had two time points. We had an early time point, day four, and a late time point, day 12. And we found a significant increase in the number of CD11B cells at our late time point, day 12, but not at day four. And this increase was apparent in all three regions of the cornea that we looked at, the central, paracentral, and peripheral regions. Secondly, we looked at chemokinoseptor expression on CD11B cells. We found an up-regulation of chemokinoseptors on these cells at day 12. And this was statistically significant, but not at day four. And this was apparent for all four chemokinoseptors that we looked at. We next looked at the expression of chemokinoligins on the ocular surface, including both the congenitalia and the cornea. And we found a statistically significant increase in the expression of CCL4 and CCL5 on the ocular surface. And lastly, we looked, using flow cytometry, we looked at the frequencies of CCL7, CCL7 on mature ancient presenting cells in draining lymph nodes. And as I said earlier, CCL7 mediates, facilitates trafficking to the lymph node. And we can see that we saw a progressive increase in the frequency of this population to day four and even more so at day 12. So in summary, we demonstrated that there are increased frequencies of CD11B APCs within the corneal stroma in dry eye disease. And this is associated with an up-regulation of chemokine receptors by these cells and an elevated expression of chemokine ligands on the ocular surface and increased homing of CCR7 expressing mature APCs to draining lymph nodes. So in conclusion, chemokine mediated mechanisms of cell trafficking have an important role in the initiation of the immune response by influencing both the migration of APCs to the ocular surface and subsequent homing of these cells to drain the lymph nodes where they can initiate an autoimmune T-cell response. I'd like to thank my mentor, Dr. Dana, and other members of the Dana lab that have helped with this work and also acknowledge funding support. Thank you, and I'd be happy to take any questions. So the first, to your first question, we're actually looking at the CD11C cells of the epithelium at the moment. The reason we decided to focus on the CD11B cells of the stroma was that they are the main antidepressant cell population of the cornea and their numbers are much larger comparably to the epithelial antidepressant cell population. So it was logical that that would be our first starting points and in terms of which cells are expressing the chemokine ligands, we think the majority of the chemokine ligands are coming from the epithelial cells or the stromal cells themselves. So non-monome cells. Yeah, no, we're looking at that, so we see. One, one, one. Yeah, we see, we see the same as the conjunctiva. We see similar trends throughout all three.