Seminar “Biotransport Mechanisms in Adaptive Immunity (in English)”
22 April at 16:30 MSK
Topic: Biotransport Mechanisms in Adaptive Immunity (in English)
Lymph nodes are immune information collection and transfer junctions, where immune cells are housed in sufficient numbers and varieties to develop effective immune responses. It is therefore the job of the lymphatic system to gather information, including free antigen, antigen presenting cells, cytokines and other immune cells/signals, from the periphery and deliver them to the node for further processing. This requires an exquisitely complex combination of active pumping, cell/antigen transport, and biological signaling between multiple cell types. Once inside the node, the information must be relayed to the correct region, where carefully orchestrated processes in specific nodal compartments result in the production of antigen-reactive cells and/or antibodies. These processes also rely on fluid flow and cytokine transport. Understanding immune system transport processes provides opportunities to modulate immune function.
Employing a combination of in vivo and excised vessel experiments, along with multiscale lumped parameter modeling, we have analyzed the effects of local pressure conditions and vasoactive substances on vessel pumping dynamics. We have also performed a series of experiments and computational simulations of flow patterns through and within lymph nodes. We have included the 3D distribution of blood vessels within lymph nodes due to the presence of significant transmural fluid movement. Agent-based models have been developed to explore the role of lymph node swelling in T cell population dynamics.
Pumping dynamics of afferent vessels, and therefore the delivery of immune information to lymph nodes, are strongly affected by variations in local pressure, including the external pressure and vasoactive effects of vaccinations. Within lymph nodes, lymph flow provides guiding cues for antigen presenting cells to interact with B and T cells. Lymph node swelling facilitates the expansion of specific T cell populations. A better understanding of these transport phenomena could lead to more relevant criteria for designing methods to modulate the immune system effectively for health benefit, including vaccines.
Speaker
Professor James E. Moore Jr., Department of Bioengineering, Imperial College London.