Background & Aims There is an unclear relationship between T-cell expression of inhibitory receptors and their ability to control viral infections. Studies of human immune cells have been mostly limited to T cells from blood, which is not always the site of infection. We investigated the relationship between T-cell location, expression of inhibitory receptors, maturation, and viral control using blood and liver cells from patients with hepatitis C virus (HCV) and other viral infections. Methods We analyzed 36 liver samples from HCV antibody-positive patients (30 from patients with chronic HCV infection, 5 from patients with sustained virologic responses [SVRs] to treatment, and 1 from a patient with spontaneous clearance), with 19 paired blood samples, and 51 liver samples from HCV-negative patients, with 17 paired blood samples. Intrahepatic and circulating lymphocytes were extracted; T-cell markers and inhibitory receptors were quantified, for total and virus-specific T cells, by flow cytometry. Results Levels of the markers PD-1 and 2B4 (but not CD160, TIM3, or LAG3) were increased on intrahepatic T cells from healthy and diseased liver tissues, compared to T cells from blood. HCV-specific intrahepatic CD8+ T-cells from patients with chronic HCV infection were distinct in that they expressed TIM3 along with PD1 and 2B4. In comparison, HCV-specific CD8+ T cells from patients with SVRs and T cells that recognized cytomegalovirus (CMV) lacked TIM3, but expressed higher levels of LAG3; these cells also had different memory phenotypes and proliferative capacity. Conclusions T cells from liver express different inhibitory receptors than T cells from blood, independent of liver disease. HCV-specific and CMV-specific CD8+ T cells can be differentiated based on their expression of inhibitory receptors; these correlate with their memory phenotype and levels of proliferation and viral control.

The synthetic random copolymer of L-glutamic acid and L-lysine (GL) is weakly or nonimmunogenic in all inbred strains of mice. Theories proposed to account for nonresponsiveness to GL include a deficient T cell repertoire, failure of antigen-presenting cells to present the antigen and/or the presence of suppressor cells. In this study we examine mechanisms for nonresponsiveness to GL. We demonstrate the existence of GL-reactive T cells which can be isolated with a relatively high frequency. These clones, which were derived following immunization of H-2d mice with poly(LGluLLysLTyr), also respond to several GL-containing polypeptides including the terpolymers of GL with phenylalanine, alanine (GLA) or leucine. Although recognition of GLA by heterogeneous T cell populations usually occurs in association with I-A determinants, these clones recognize GLA, as well as the other GL-containing polymers, in association with I-E determinants. Analysis of the antigen and alloreactivity patterns of these clones indicated that they expressed distinct antigen receptors. These studies imply that the T cell repertoire of "nonresponder" H-2d mice includes multiple GL-reactive T cell clones and that the antigen-presenting cells of these mice are effective in processing and presenting GL.

Chicken spleen and bursa cells were examined for the percentage of Fc receptor-bearing cells. Rosette formation was done with chicken 7S antibody-sensitized sheep erythrocytes and was inhibited by heat-aggregated chicken Ig. In the spleen, the percentage was found to increase with age to approximately 26% at 7 to 12 weeks. In contrast, only 3 to 5% of bursa cellss at this age demonstrated Fc receptors. Sleens from bursectomized chickens had 7--10% Fc receptor-bearing cells. In an attempt to determine a possible role of the C3 receptor on migration patterns, the effect of cobra venom factor (CVF) on the localization of transferred lymphoid cells was examined. Pretreatment of recipients with enough CVF to lower mean C3 levels to 11% of controls failed to affect follicular B cell localization in mice at either 24 or 48 h after transfer. Localization of thymus or bursa cells in chickens was similarly unaffected by CVF pretreatment. The possible roles of Fc and C3 receptors on migration of B lymphocytes into follicles and germinal centers were discussed.