Research

Description of our Research

Leukocyte Traffic and the Immune Response

Leukocyte migration from the blood and lymph into tissues is critical for generation of normal immune responses. Abnormal leukocyte traffic contributes to the pathogenesis of all inflammatory diseases and several other diseases, such as cancer. We study the molecular mechanisms and functional implications of leukocyte migration in the body. We have identified several new adhesion molecules (e.g. vascular adhesion protein-1 (VAP-1), CD73, stabilin-1, plasmalemma vesicle associated protein (Plvap)) on blood and lymphatic vessels and leukocytes, which mediate different steps of leukocyte extravasation from the vessels. We have also studied the therapeutic value of modulating the function of these and other adhesion receptors in inflammation and cancer. We also elucidate the differentiation pathways of monocytes/macrophages by studying the role of the developmental origin and tissue niche for their plasticity and functions. In addition, we are interested in defining the routes by which antigens enter the lymph node parenchyma via the lymphatic vasculature during the triggering of immune responses. As a separate line of research, we have analyzed the value of adhesion molecules and cytokines as biomarkers of disease in population and patient cohorts.

Selected Publications (from 2014 onwards)

1. Maksimow M, Kyhälä L, Nieminen A, Kylänpää L, Aalto K, Elima K, Mentula P, Lehti M, Puolakkainen P, Yegutkin GG, Jalkanen S, Repo H, Salmi M. Early prediction of persistent organ failure by soluble cd73 in patients with acute pancreatitis Crit Care Med 42, 2556-2564, 2014.
2. Rantakari P, Auvinen K, Jäppinen J, Kapraali M, Valtonen J, Karikoski M, Gerke H, , IIftakhar-E-Khuda I, Keuschnigg J, Umemoto E, Tohya K, Miyasaka M, Elima K, Jalkanen S, Salmi M. Plvap controls the entry of antigens to conduits and lymphocyte transmigration to parenchyma in the lymphatic sinus of lymph nodes. Nat Immunol 16:386-96, 2015.
3. Palani S, Elima K , Ekholm E,  Jalkanen S, Salmi M. Monocyte stabilin-1 suppresses the activation of Th1 lymphocytes. J Immunol 196:115-123, 2016.
4. Rantakari P, Jäppinen N, Lokka E, Mokkala E, Gerke H, Peuhu E, Ivaska J, Elima K, Auvinen K, Salmi M.. Fetal liver endothelium regulates the seeding of tissue-resident macrophages. Nature, 538:392-396, 2016.
5. Santalahti K, Havulinna A, Maksimow M, Zeller T, Blankenberg S,Vehtari A, Joensuu H, Jalkanen S, Salomaa V, Salmi M. Plasma levels of HGF and PlGF predict mortality in a general population: a prospective cohort study. J Intern Med, 282(4):340-352, 2017.
6. Jäppinen N, Félix I, Lokka E, Tyystjärvi S, Pynttäri A, Lahtela T, Gerke H, Elima K, Rantakari P, Salmi M. Fetal-derived macrophages dominate in adult mammary glands. Nat Commun. 10:281, 2019. doi: 10.1038/s41467-018-08065-1
7. Kähäri L, Fair-Mäkelä R, Auvinen K, Rantakari P, Jalkanen S, Ivaska J, Salmi M. Transcytosis route mediates rapid delivery of intact antibodies to draining lymph nodes. J Clin Invest. 129:3086-3102, 2019.
8. Jalkanen S, Salmi M. Lymphatic endothelial cells of the lymph node. Nat Rev Immunol. 2020 Feb 24. doi: 10.1038/s41577-020-0281-x. Online ahead of print.