Comparative Analyses of Thymocyte and Thymic Low‐Density Adherent Cell Functions

Abstract

Thymocytes which have developed in the C3H thymus showed depressed proliferative responses to stimulation with anti‐CD3 antibody as compared with those which have developed in the thymus of other strains of mice (i.e. AKR). The present study was conducted to analyze immunological functions of the thymic stromal cell population (low‐density adherent cells, LDAC) in the C3H mice using allogeneic bone marrow (BM) chimeras established by BM transplantation in the reciprocal combination of AKR and C3H mice as donor or recipient. The thymic LDAC from C3H mice or the [AKR(donor)→C3H(recipient)] chimeras contained a high proportion of Mac‐1+ cells as compared to AKR mice or the [C3H→AKR] chimeras. The proportion of Mac‐1+ cells paralleled the IL‐1‐ and PGE2‐secreting ability of the LDAC cultured either in the presence or absence of LPS and also paralleled the antigen‐presenting cell functions of the LDAC. Furthermore, after anti‐CD3 stimulation the PGE2 inhibited more profoundly proliferative responses of [AKR→C3H] or normal C3H thymocytes than those of the [C3H→AKR] chimera or normal AKR thymocytes. A PGE2 inhibitor, indomethacin, reversed the depressed responses of the thymocytes which had developed in the C3H thymus. These findings suggest that the lower responsiveness of thymocytes from [AKR→C3H] chimeras to anti‐CD3 stimulation may be attributable to large amounts of PGE2 secreted by LDAC and/or to increased sensitivity of thymocytes themselves to PGE2.

Generation of NK1.1+T cell antigen receptor α/β+thymocytes associated with intact thymic structure

“…[HE staining (A, B, G, and H) ϭ ϫ40; immunohistochemical staining (C, D, E, and F) ϭ ϫ400. ] of the thymus (15,16,(25)(26)(27)(28)(29), although it has been shown that macrophages and dendritic cells derived from BM precursors were partially involved in functional maturation of thymocytes (30). The present findings demonstrated once again that the developmental arrest of NK1.1 ϩ TCR-␣͞␤ ϩ thymocytes in aly͞aly mouse is associated with structural abnormalities of the thymus that are peculiar to the aly͞aly mouse.…”

Csk overexpression reduces several monokines and nitric oxide productions but enhances prostaglandin E2 production in response to lipopolysaccharide in the macrophage cell line J774A.1

“…The secreted PGE2 was quantitated using a competitive enzyme immunoassay kit (Cayman). The assays were carried out according to the protocol supplied with the kit as described [24].…”