We recently demonstrated a codominant role of C5aR and FcγRIII in the initiation of IgG immune complex-mediated inflammation in mice. In this study, we investigated the relative contribution of FcγRIII in the generation of several cytokines during experimental hypersensitivity pneumonitis/alveolitis in vivo. Induction of immune complex-alveolitis in C57BL/6 mice resulted in strong accumulation of neutrophils into the lung and enhanced chemotactic activity within bronchoalveolar lavage fluid accompanied by an increased production of the proinflammatory cytokines TNF-α and IL-1β as well as the ELR-CXC chemokines macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC). FcγRIII-deficient C57BL/6 mice (FcγRIII−/−) showed a marked reduction of the inflammatory response due to decreased production of TNF-α, IL-1β, and MIP-2. Results obtained in C57BL/6 mice either lacking the TNF-α class I receptor (TNF-αRI−/−) or treated with neutralizing anti-TNF-α mAb demonstrated an essential contribution of TNF-α for mediating IL-1β release, neutrophil influx, and hemorrhage. Surprisingly, MIP-2 and KC chemokine levels remained largely unaffected in TNF-αRI−/− mice or after functional inhibition of TNF-α. These data suggest that in immune complex alveolitis, the activation of FcγRIII may induce divergent downstream effector pathways with TNF-α acting independently of CXC chemokines to trigger the inflammatory response in C57BL/6 mice.

1. The generation of superoxide anions (02-) by intact pig coronary artery rings was measured using a lucigenin-enhanced chemiluminescence technique and a histochemical technique with Nitroblue Tetrazolium (NBT) staining. 2. Isolated arteries with intact endothelium generated 02 at a rate of 9 0 + 0-8 pmol min' (mg dry weight)-1; this rate was diminished by about 24% when the endothelium was removed. The NBT staining of arterial ring preparations showed formazan precipitation mainly in the intima. Arterial rings were pretreated with diethylthiocarbamate in order to inhibit Cu-Zn superoxide dismutase (SOD) activity which increased the 2-generation by 184 + 55% (n = 10; P < 0-01). Stimulation of protein kinase C with phorbol 12-myristate 13-acetate (5 FM) enhanced endothelium-dependent 2-generation by 136 + 20% (n = 19; P< 0-01). Neither stimulation with bradykinin or substance P, nor inhibition with NG-nitro-L-arginine methyl ester of endothelial nitric oxide synthase had a significant effect on 02-generation. In contrast, the inhibition of flavoproteins with diphenyliodonium 4. The results suggest that intact coronary arteries do generate O2-under basal conditions and that the endothelial layer significantly contributes to this phenomenon. This generation of 02-is greatly influenced by intrinsic SOD activity. It is suggested that basal vascular 02-generation is mainly due to membrane-bound NAD(P)H oxidase activity and/or tetrahydrobiopterin-dependent processes.

This study was designed to determine whether or not a number of diverse rhythmic variables in the rat could be synchronized to meal timing. This was tested by restricting the availability of food; once during each 24-hour period an unrestricted quantity of food was made available for a 4-hour period to four different groups at different phases of the light-dark cycle, and the rhythms of the variables studied in the different groups were compared. Liver glycogen and serum glucose did synchronize to or were strongly influenced by feeding schedules; corticosterone and the several enzymes measured seemed to reflect an interaction of both the restricted feeding schedule and the light-dark cycle. The mitotic index in the corneal epithelium in all groups remained remarkably synchronized to the light-dark cycle and was altered only minimally by restricted meal timing. All groups on restricted feeding schedules gained less weight than the group fed ad libitum and maintained on a light-dark cycle. These studies caution against assuming that all body functions react in the same manner to different synchronizers; and they emphasize that one must not generalize about the synchronizing effect of meal-timing or even the light-dark cycle.

In conclusion, a model of cellular adrenocortical transplantation was established. The results show that syngeneic transplantation resulted in physiological corticosterone levels early after transplantation, whereas fully MHC-incompatible grafts were rejected. Recipients of Kb-transgenic grafts showed unimpaired adrenocortical function, but did not tolerize toward Kb-transgenic skin grafts. Possible mechanisms include a local immunomodulatory effect of glucocorticoids secreted by the graft and a low immunogenicity of the relatively small numbers of transplanted cells.