Thymic nurse cells exclusively bind and internalize CD4+CD8+ thymocytes
1992; Elsevier BV; Volume: 140; Issue: 2 Linguagem: Inglês
10.1016/0008-8749(92)90214-a
ISSN1090-2163
AutoresYang Li, Mark Pezzano, Deborah Philp, Vincent E. Reid, J. Guyden,
Tópico(s)Immunotherapy and Immune Responses
ResumoThymic nurse cells (TNC) contain 20–200 thymocytes within specialized vacuoles in their cytoplasm. The purpose of the uptake of thymocytes by TNCs is unknown. TNCs also have the capacity to present self-antigens, which implies that they may serve a function in the process of thymic education. We have recently reported the development of thymic nurse cell lines that have the ability to bind and internalize T cells. Here, we use one of these TNC lines to identify the thymocyte subpopulation(s) involved in this internalization process. TNCs exposed to freshly isolated thymocytes bind and internalize CD4 and CD8 expressing thymocytes (CD4+CD8+ or double positives) exclusively. More specifically, a subset of the double-positive thymocyte population displayed binding capacity. These double-positive cells express cell surface αβ type T cell antigen receptor (TCR), as well as CDϵ. Binding was not inhibited in the presences of antibodies against CD3, CD4, CD8, Class I antigens, or Class II antigens. These results describe two significant events in T cell development. First, TNCs exclusively bind and internalize a subset of αβ TCR expressing double-positive T cells. Also, binding is facilitated through a mechanism other than TCR recognition of major histocompatibility complex antigens. This suggests that thymocyte internalization may be independent of the process used by TNCs to present self-antigen.
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