Phenotypic characteristics of human type II alveolar epithelial cells suitable for antigen presentation to T lymphocytesReport as inadecuate

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Respiratory Research

, 12:15

First Online: 01 December 2011Received: 14 September 2010Accepted: 24 January 2011


BackgroundType II alveolar epithelial cells AECII are well known for their role in the innate immune system. More recently, it was proposed that they could play a role in the antigen presentation to T lymphocytes but contradictory results have been published both concerning their surface expressed molecules and the T lymphocyte responses in mixed lymphocyte cultures. The use of either AECII cell line or fresh cells could explain the observed discrepancies. Thus, this study aimed at defining the most relevant model of accessory antigen presenting cells by carefully comparing the two models for their expression of surface molecules necessary for efficient antigen presentation.

MethodsWe have compared by flow cytometry the surface expression of the major markers involved in the immunological synapse on the A549 cell line, the most popular model of type II alveolar epithelial cells, and freshly isolated cells. HLA-DR, CD80, CD86, ICOS-L, CD54, CD58 surface expression were studied in resting conditions as well as after IFN-γ-TNF-α treatment, two inflammatory cytokines, known to modulate some of these markers.

ResultsThe major difference found between the two cells types was the very low surface expression of HLA-DR on the A549 cell line compared to its constitutive expression on freshly isolated AECII. The surface expression of co-stimulatory molecules from the B7 family was very low for the CD86 B7-2 and ICOS-L B7-H2 and absent for CD80 B7-1 on both freshly isolated cells and A549 cell line. Neither IFN-γ nor TNF-α could increase the expression of these classical co-stimulatory molecules. However CD54 ICAM-1 and CD58 LFA-3 adhesion molecules, known to be implicated in B7 independent co-stimulatory signals, were well expressed on the two cell types.

ConclusionsConstitutive expression of MHC class I and II molecules as well as alternative co-stimulatory molecules by freshly isolated AECII render these cells a good model to study antigen presentation.

Electronic supplementary materialThe online version of this article doi:10.1186-1465-9921-12-15 contains supplementary material, which is available to authorized users.

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Author: Véronique Corbière - Violette Dirix - Sarah Norrenberg - Mattéo Cappello - Myriam Remmelink - Françoise Mascart


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