Characteristics of splenic CD8+ T cell exhaustion in patients with hepatitis C.

There is increasing interest in the role of T cell exhaustion and it is well known that the natural history of chronic hepatitis C virus infection (HCV) is modulated by CD8(+) T cell immunobiology. There are many pathways that alter the presence of exhaustive T cells and, in particular, they are functionally impaired by inhibitory receptors, such as programmed death-1 (PD-1) and T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3). We obtained spleen, liver and peripheral blood (before and after splenectomy) lymphoid cells from 25 patients with HCV-related cirrhosis undergoing liver transplantation for end-stage disease or splenectomy for portal hypertension. In all samples we performed an extensive phenotypic study of exhaustion markers [PD-1, Tim-3, interferon (IFN)-γ) and their ligands (PD-L1, PD-L2, galectin-9] in CD8(+) T cell subpopulations (both total and HCV-specific) and in antigen-presenting cells (APC; monocytes and dendritic cells). In the spleen, total and HCV-specific CD8(+) T cells demonstrated enhanced markers of exhaustion, predominantly in the effector memory subpopulation. Similarly, splenic APC over-expressed inhibitory receptor ligands when compared to peripheral blood. Finally, when peripheral blood CD8(+) T cells were compared before and after splenectomy, markers of exhaustion were reduced in splenic CD8(+) T cells and APC. Our data in HCV-related cirrhosis suggest that CD8(+) T cells in the spleen manifest a significantly higher exhaustion compared to peripheral blood and may thus contribute to the failure to control HCV. Counteracting this process may contribute to inducing an effective immune response to HCV.

Intercellular localization of leukotoxin (9:10-epoxy-12-octadecenoic acid) in lungs in rats by an immunoelectron microscopy.

In this paper intercellular localization of leukotoxin (9:10-epoxy-12-octadecenoic acid, LTx) in neutrophils and alveolar macrophages of rats exposed to the 100% oxygen was demonstrated by a pre-embedding method of an immunoelectron microscopy. The Sprague-Dawley rats were treated with the 100% oxygen for 72 hrs, and the lungs were stained with anti-LTx IgG (Fab) by an immunocytochemical method and examined by a transmission electron microscope. The positive reactions with anti-LTx IgG (Fab) was shown strongly in the rough-surfaced endoplasmic reticulum (rER) and cell membranes of the neutrophils and alveolar macrophages. This result indicates that LTx is produced in biomembrane-rich organelle of alveolar macrophages as well as neutrophils dependently on the treatment period under hyperoxia conditions, suggesting that LTx is closely related to biological reactions and is an important chemical mediator on pulmonary diseases.