A possible role of the peptide binding protein (PBP) 72/74 in antigen processing and presentation has been recently suggested in mice. In order to evaluate a possible analogous role of a PBP72/74-related protein in humans, immunoelectron microscope investigations, functional studies, and immunofluorescence analyses were performed on normal human peripheral antigen-presenting cells. We demonstrated that the determinant recognized by antiheat shock protein (HSP) 72/73 monoclonal antibody (MoAb) is constitutively expressed on the cell surface of monocytes as well as of B cells. Moreover, the capability of monocytes to present a recall antigen to T cells was significantly decreased when preincubated with an anti-HSP72/73 MoAb. These data add further strength to a potential role of a protein related to human PBP72/74 homologue in antigen processing and/or presentation. Finally, the capability of anti-HSP72/73 MoAb to impair the ability of fixed monocytes to present a synthetic peptide demonstrates that cell surface- localized PBP72/74-related protein could play a role in antigen presentation.
The aim of this study was to evaluate the presence of inflammatory phenomena and elastic fiber phagocytosis in mid-dermal elastolysis. The pathological and ultrastructural features of 5 Caucasian female patients (ranging from 26 to 40 years) with acquired diffuse asymptomatic areas of skin wrinkling have been reviewed. The clinical features of all cases were characteristic of this condition and only in one patient were erythematous urticaria-like, non pruriginous patches also observed. In 4 cases a history of prolonged sun bathing was present and in 3 cases there was a short history of oral contraception. The pathological study confirmed the typical absence of elastic fibers in the midreticular dermis. In two cases elastic fibers were still detectable in the periadnexal dermis. Hematoxylin and eosin sections showed a mild perivascular infiltrate in two cases, while in three patients histiocytes were scattered among collagen bundles. Multinucleated giant cells containing fragmented elastic fibers were detectable in one patient. Ultrastructural analysis revealed large mononuclear cells with phagocytic aspects toward elastic fibers in all cases.
Electron microscopy examination of liver biopsies from 8 patients with chronic non-A, non-B hepatitis revealed ultrastructural changes similar to those previously described in chimpanzees with experimentally induced acute non-A, non-B hepatitis. These changes consisted of intranuclear clusters of electron-dense, 15-27-nm particles that were detected in five out of the eight patients and of circular cytoplasmic structures that were present in seven cases. Other cytoplasmic abnormalities found in our patients related to the presence of curved membranes apparently developing from apposition of two cisternae of endoplasmic reticulum. In contrast with what has been reported in infected chimpanzees, the nuclear and cytoplasmic changes were not mutually exclusive in our patients, but coexisted in four of them.
Three ligands have been described for the leucocyte integrin LFA-1, namely intercellular adhesion molecule (ICAM)-1, ICAM-2, and ICAM-3. ICAMs show differences in tissue distribution and inducibility. The recently described ICAM-3 is highly expressed on resting lymphocytes, monocytes and neutrophils. Here, we demonstrate that the whole human epidermal Langerhans cell (LC) population expresses this molecule. Immunohistochemical staining of skin sections with an anti-ICAM-3 monoclonal antibody displayed reactivity with dendritic epidermal cells regularly distributed along the epidermis. Highly-sensitive immunoelectron microscopy procedures, performed on freshly suspended epidermal cells both at transmission and scanning electron microscopic levels, enabled demonstration that the whole LC population expresses cell surface ICAM-3. In contrast, keratinocytes and melanocytes were consistently negative. The prominent expression of ICAM-3 by resident LC could imply a crucial part for this molecule in leucocyte-intercellular interactions in the skin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.