Background: Interleukin-7 (IL-7) is a pivotal lymphopoietic cytokine that plays also a critical role in peripheral T cell homeostasis. IL-7 exerts strong antiapoptotic, immunomodulatory and proliferative effects on target cells. In the last years, several studies analyzed the biology of IL-7 in vitro also in order to find a rationale for a possible use of it as a new therapeutic agent. Objectives: Most of the data describing IL-7 biology derive from animal models or from studies performed on human cells in vitro. The aim of our work is to analyze the antiapoptotic, immunomodulatory, and prolipherative effects of IL-7 on human T lymphocytes, in a more physiologic and complex ex vivo lymphoid tissue model obtained from human tonsils, derived from the protocol proposed by Glushakova et al.1 Methods: Human tonsils from 14 routine therapeutic tonsillectomies were processed according to Glushakova's protocol and maintained in culture in an FCS-enriched medium culture, in the absence or in presence of IL-7 at 10 and 20 ng/ml. Single cell suspensions from the cultured tissue blocks were analyzed by flow cytometry for the expression of AnnexinV, Ki67, CD127, CD25, CCR5 and CXCR4. Parallel tissue blocks were prepared for hystological and immunohystochemical studies. Twenty different cytokines and chemokines released in the culture medium in the three experimental conditions were evaluated using a multiplex bead array assay (Luminex). Results: IL-7 at 10 and 20 ng/ml in the medium culture reduced the levels of spontaneous apoptosis of T lymphocytes: the greatest antiapoptotic effect, was seen at day 4 of culture. IL-7 didn't elicit a proliferative response in T lymphocytes during the first four days of culture. IL-7, downregulated IL-7Ra expression by T cells in a dose dependent manner. The expression of T cell activation markers (CD25 and HLA-DR) wasn't significantly affected by IL-7 exposure. IL-7 reduced the spontaneous increase of CCR5 membrane expression seen on T cells maintained in neutral culture conditions. CXCR4 expression wasn't significantly affected by the addition of IL-7. We observed a significant association between the exposure to IL-7 and the release of TNF-α, IL-4, MIP-1β, MIG, and SDF-1β in the culture medium. Conclusion: IL-7 reduces the levels of spontaneous apoptosis and modulates the immunophenotype and the pattern of cytokine and chemokine secretion of T lymphocytes in human lymphoid ex vivo tissue cultures. Our model can therefore represent a useful tool for studying and dissecting the immunomodulatory effects of IL-7 administration or neutralization in a more physiologic and complex human in vitro system. Studies performed on this model could help scientists in finding new rationales for the use of this cytokine or its inhibition as novel therapeutic tools for human disease.
ANTIAPOPTOTIC AND IMMUNOMODULATORY EFFECTS OF INTERLEUKIN 7 IN AN EX VIVO MODEL OF HUMAN LYMPHOID TISSUE
DELLA TORRE E;Lorenzo Dagna;
2010-01-01
Abstract
Background: Interleukin-7 (IL-7) is a pivotal lymphopoietic cytokine that plays also a critical role in peripheral T cell homeostasis. IL-7 exerts strong antiapoptotic, immunomodulatory and proliferative effects on target cells. In the last years, several studies analyzed the biology of IL-7 in vitro also in order to find a rationale for a possible use of it as a new therapeutic agent. Objectives: Most of the data describing IL-7 biology derive from animal models or from studies performed on human cells in vitro. The aim of our work is to analyze the antiapoptotic, immunomodulatory, and prolipherative effects of IL-7 on human T lymphocytes, in a more physiologic and complex ex vivo lymphoid tissue model obtained from human tonsils, derived from the protocol proposed by Glushakova et al.1 Methods: Human tonsils from 14 routine therapeutic tonsillectomies were processed according to Glushakova's protocol and maintained in culture in an FCS-enriched medium culture, in the absence or in presence of IL-7 at 10 and 20 ng/ml. Single cell suspensions from the cultured tissue blocks were analyzed by flow cytometry for the expression of AnnexinV, Ki67, CD127, CD25, CCR5 and CXCR4. Parallel tissue blocks were prepared for hystological and immunohystochemical studies. Twenty different cytokines and chemokines released in the culture medium in the three experimental conditions were evaluated using a multiplex bead array assay (Luminex). Results: IL-7 at 10 and 20 ng/ml in the medium culture reduced the levels of spontaneous apoptosis of T lymphocytes: the greatest antiapoptotic effect, was seen at day 4 of culture. IL-7 didn't elicit a proliferative response in T lymphocytes during the first four days of culture. IL-7, downregulated IL-7Ra expression by T cells in a dose dependent manner. The expression of T cell activation markers (CD25 and HLA-DR) wasn't significantly affected by IL-7 exposure. IL-7 reduced the spontaneous increase of CCR5 membrane expression seen on T cells maintained in neutral culture conditions. CXCR4 expression wasn't significantly affected by the addition of IL-7. We observed a significant association between the exposure to IL-7 and the release of TNF-α, IL-4, MIP-1β, MIG, and SDF-1β in the culture medium. Conclusion: IL-7 reduces the levels of spontaneous apoptosis and modulates the immunophenotype and the pattern of cytokine and chemokine secretion of T lymphocytes in human lymphoid ex vivo tissue cultures. Our model can therefore represent a useful tool for studying and dissecting the immunomodulatory effects of IL-7 administration or neutralization in a more physiologic and complex human in vitro system. Studies performed on this model could help scientists in finding new rationales for the use of this cytokine or its inhibition as novel therapeutic tools for human disease.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
