Phagocytic cells of the thymic reticulum interact with thymocytes via extracellular matrix ligands and receptors.
We previously showed that, in the context of thymic epithelial cells, thymocyte migration is partially controlled by extracellular matrix (ECM)-mediated interactions. Herein we evaluated whether these interactions could be involved in cell migration related events in the context of non-epithelial cells of the thymic microenvironment, the phagocytic cells of the thymic reticulum (PTR). We first showed, by immunocytochemistry, cytofluorometry, and RT-PCR, that PTR produce ECM components, including fibronectin and laminin, and express the corresponding integrin-type receptors, VLA-4, VLA-5, and VLA-6. Thymocytes adhere onto PTR monolayers, with immature CD4(+)CD8(+) cells being predominant. Importantly, such an adhesion is partially mediated by ECM ligands and receptors, since it was impaired by anti-ECM or anti-ECM receptor antibodies. Conjointly, our data reveal that the ECM-dependence for thymocyte adhesion onto the thymic microenvironment is not restricted to the epithelial cells, being also seen when they encounter non-epithelial phagocytic cells.
Laboratory on Thymus Research, Department of Immunology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
Silvana
S
Ayres-Martins
Joseli
J
Lannes-Vieira
Désio Aurélio
DA
Farias-De-Oliveira
José Marques
JM
Brito
Déa Maria Serra
DM
Villa-Verde
Wilson
W
Savino
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology*; D005260:Female; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D010586:Phagocytes / Q000502:physiology*; D013950:Thymus Gland / Q000502:physiology*
D008024:Ligands