Endocytosis of the TCR/CD3 complex and the class-I major histocompatibility complex in a human T cell line.

We investigated the expression of the T cell receptor (TCR)/CD3 complex on a CD4-positive human T cell lymphoma cell line treated with phorbol myristate acetate (PMA) and/or CA2+ ionophore using fluorescence flow cytometry and fluorescence microscopic analysis. PMA induced a significant decrease in the expression of the CD3 complex on the cell membranes. Fluorescence microscopy confirmed that the down regulation is due to internalization of the antigens. Ca2+ ionophore treatment had no effect on the internalization of the CD3 complex. Double staining revealed that the vesicles containing the internalized CD3 complex and those containing intra-cytoplasmic class I major histocompatibility complex antigen had similar distribution in the PMA-stimulated cells, implying coexistence of these two antigens in a cytoplasmic perinuclear distribution.     

Effects of pertussis toxin and indomethacin on murine lymphocytes in the bronchoalveolar lavage fluids

The total number of lymphocytes in the bronchoalveolar lavage (BAL) fluids significantly increased in mice injected intravenously with pertussis toxin (PT), while the absolute number of alveolar macrophages markedly decreased. This finding probably reflects the lymphocyte accumulation in interstitial spaces as we previously observed in mice injected with PT. In addition, indomethacin, at lower dosage (0.5 mg/kg) prevented peripheral lymphocytosis and lymphocyte accumulation in the alveolar spaces of the lungs of mice injected with PT. These results provide evidence that PT is responsible for lymphocyte accumulation together with a marked decrease of alveolar macrophages in the lungs of treated mice; moreover, indomethacin is effective in preventing bronchoalveolar changes caused by PT.     

Very-low-protein diets lead to reduced food intake and weight loss,linked to inhibition of hypothalamic mTOR signaling,in mice

1. Download : Download high-res image (252KB)
2. Download : Download full-size image