Estudo do envolvimento de CC quimiocinas e moléculas de adesão no recrutamento de linfócitos T γδ em reações inflamatórias de origem alérgica. / Study of the envolvement of CC-chemokines and adhesion moleculares conscription of lymphocyte T gama delta into the inflammatory reactions of allergic origin.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

γδ T lymphocytes play an important role during allergic reactions, performing effector and regulatory functions. Chemokines and adhesion molecules are crucial for lymphocyte migration in response to several stimuli. However, the mechanisms by which γδ T lymphocytes migrate into the inflammatory site during allergic reactions have not been described yet. In the present study, the role of chemokines, selectins and integrins on γδ T cell migration after the intrathoracic challenge with ovalbumin into sensitized mice was investigated. Ovalbumin stimulation induced an increase in γδ T lymphocyte numbers in mice pleural cavities within 12 hours, which remained significantly above control levels until 96 hours. Such accumulation was accompanied by an increase in blood counts within 48 hours. The antigenic challenge also induced an increase in the numbers of γδ T lymphocytes expressing CCR2, CCR5 and CCR9 in the pleural cavity from 12 to 72 hours and in blood within 48 hours. It also induced an increase in the expression of these molecules on γδ T cells from thoracic lymph nodes 48 hours after stimulation. The levels of CCL2, CCL3, CCL5 and CCL25 were increased in pleural washes recovered 24 hours after challenge, and were mainly produced by pleural macrophages. The in vivo neutralization of CCL2, but not of CCL3, CCL5 or CCL25, significantly inhibited γδ T lymphocyte migration into the mice pleural cavity 24 hours after challenge. In addition, the pre-treatment with antibodies anti-CCL2, anti-CCL3 and anti-CCL5 was able to inhibit the increase in eosinophil numbers in ovalbumin-challenge mice. The in vitro neutralization of CCL2 inhibited γδ T cell chemotaxis induced by pleural washes recovered from stimulated animals, confirming the direct role of this chemokine on γδ T lymphocytes. Confirming such data, the antigenic challenge failed to induce an increase in γδ T lymphocyte numbers in the pleural cavities, blood and lymph nodes of CCR2 knockout mice. We also observed an increase in the expression of L-selectin on γδ T lymphocytes recovered from thoracic lymph nodes of challenged mice. γδ T cells recovered from blood of stimulated animals showed a higher expression of L-selectin when compared to cells recovered from pleural cavity, suggesting the shedding of this molecule. The antigenic challenge also induced an accumulation of pleural γδ T cells expressing CD49d, α4β7-integrin, CD11a and CD11b within 48 hours. The in vitro blockade of selectins, L-selectin, CD49d and α4β7-integrin (but not of P-selectin, E-selectin or CD11a) was able to inhibit γδ T lymphocyte transmigration towards pleural washes recovered from challenge mice. The in vivo pre-treatment with fucoidan or monoclonal antibodies against L-selectin was able to significantly inhibit the influx of these cells into the allergic site 48 hours after the stimulus. Such results suggest an important function of L-selectin and α4-integrins in γδ T lymphocyte migration during allergic responses, and demonstrate that CCL2 plays a central role on γδ T cell migration into the inflammatory site during ovalbumin-induce allergic pleurisy in mice.

ASSUNTO(S)

linfócitos camundongos imunologia lymphocytes linfócitos t chemokines mice quimiocinas t-lymphocytes quimiocinas cc chemokines, cc

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