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Antigen Reactivity (antigen + reactivity)
Selected AbstractsMultispecific responses by T cells expanded by endogenous self-peptide/MHC complexesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2007Guifang Cai Abstract The paradox of autoreactivity to self-peptides in physiological as opposed to pathological immune responses is not well understood. Here, we directly examined the human T cell response to endogenous self-peptides in a series of healthy subjects. CFSE-labeled T cells were stimulated with unmanipulated antigen-presenting cells containing endogenous self-antigen, and the resulting CD4+ populations entering into cell cycle (CFSElow) or non-proliferating CD4+ cells (CFSEhigh) were single-cell sorted, cloned and screened against a panel of self-antigens and microbial recall antigens to interrogate their antigen reactivity. The percentage of CD4+ T cells entering cell cycle in response to self-peptide/MHC was calculated to be 0.04%, and entry into cell cycle was dependent upon CD28 costimulation. Clones derived from CFSElow T cells exhibited significantly greater cross-reactivity to multiple antigens than CFSEhigh clones or other CD4+ clones generated after microbial antigen stimulation. Sequencing the TCR, chains indicated that CFSElow clones were indeed clonal. These data demonstrate that T cell clones generated on stimulation by endogenous self-peptides exhibit a high degree of multispecificity, and we speculate that their multispecificity is based upon recognition of shared-backbone MHC determinants. [source] Ultrastructural localization of glycodelin oligosaccharides Le-x and Le-y in human seminal vesicles by immunogold stainingJOURNAL OF ANATOMY, Issue 3 2007M. Piludu Abstract Histo-blood group antigens Le-x and Le-y are oligosaccharidic terminals that characterize many glycoproteins in the human tissues. In seminal plasma, they are expressed as part of the so-called glycodelin S, which is suggested to regulate sperm capacitation/decapacitation. It has recently been demonstrated that the core protein of glycodelin S is secreted by seminal vesicles. Here we show that epithelial cells of human seminal vesicles also release the Le-x and Le-y antigens. The presence of these substances in secretory material was revealed by means of an immunogold staining method in normal surgical samples. The results suggest that glycodelin S is secreted by seminal vesicles in its finished glycosylated form. Moreover, antigen reactivity was also revealed associated with plasma membranes. [source] Modulation of ABH histo-blood group antigen expression in normal and myasthenic human thymus,APMIS, Issue 10 2006VICTORIA S. SARAFIAN The role of ABH histo-blood group antigens (HBGA) in intercellular communication during normal and pathological processes is still uncertain. The present work investigates the expression of ABH HBGA in epithelial cells and lymphocytes in normal thymus, and characterizes the modulation of their immunoreactivity during myasthenic transformation. Immunohistochemistry and immunoelectron microscopy were applied on normal young thymus and on myasthenia gravis-associated thymomas and thymic hyperplasias. The Hassall's corpuscules in the thymus of young individuals were homogeneously stained for HBGA, while in hyperplastic glands only their central part was positive. Stromal epithelial cells permanently expressed HBGA in all tissue samples. In thymomas, mainly the lymphocytes in close proximity to antigen expressing epithelial cells were positive, while in the hyperplastic gland the most intensely stained lymphocytes were those within Hassall's corpuscules. Novel evidence for modulation of ABH antigen reactivity in normal and myasthenic human thymus is presented. It suggests that HBGA might participate in the regulation of the cross-talk in the thymocyte microenvironment throughout the ontogeny, as well as during the myasthenic transformation. [source] Initial pattern of angiogenesis and bone formation following lateral ridge augmentation using rhPDGF and guided bone regeneration: an immunohistochemical study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 1 2010Frank Schwarz Abstract Objectives: To evaluate (i) the effects of rhPDGF-BB on localized ridge augmentation using a natural bone mineral (NBM), and (ii) the influence of a collagen membrane (CM) on factor activity. Materials and methods: Chronic-type alveolar ridge defects (n=4 dogs) were randomly allocated in a split-mouth design as follows: upper jaw: NBM+rhPDGF-BB+CM (test) vs. NBM+rhPDGF-BB (control), and lower jaw: NBM+rhPDGF-BB+CM (test) vs. NBM+CM (control). After 3 weeks, dissected blocks were prepared for immunohistochemical (angiogenesis , TG) and histomorphometrical analysis [e.g. augmented area (AA), mineralized , (MT), non-mineralized tissue (NMT) (mm2)]. Results: Lower jaw: TG and mineralization of AA mainly originated from the defect borders. Test sites revealed a pronounced TG antigen reactivity and higher AA and MT values (mean and median). Upper jaw: control sites revealed a dislocation of AA in caudal direction, but also an improved vascularization in the peripheral wound area. While MT values (median) appeared to be comparable in both groups, AA, NMT, and NBM values (mean and median) tended to be higher at test sites. Conclusions: It was concluded that (i) rhPDGF-BB soak-loaded on NBM might have the potential to support bone formation at chronic-type lateral ridge defects, and (ii) the application of CM did not seem to interfere with the factor activity, but ensured a stabilization of the graft particles. To cited this article: Schwarz F, Ferrari D, Podolsky L, Mihatovic I, Becker J. Initial pattern of angiogenesis and bone formation following lateral ridge augmentation using rhPDGF and guided bone regeneration: an immunohistochemical study in dogs. Clin. Oral Impl. Res. 21, 2010; 90,99. [source] Lateral ridge augmentation using particulated or block bone substitutes biocoated with rhGDF-5 and rhBMP-2: an immunohistochemical study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 7 2008Frank Schwarz Abstract Objectives: The aim of the present study was to immunohistochemically evaluate lateral ridge augmentation using a particulated (BOG) or block (BOB) natural bone mineral biocoated with rhGDF-5 and rhBMP-2 in dogs. Materials and methods: Three standardized box-shaped defects were surgically created at the buccal aspect of the alveolar ridge in each quadrant of eight beagle dogs. After 2 months of healing, the chronic-type defects were randomly allocated in a split-mouth design to either (i) BOG or (ii) BOB biocoated with (a) rhGDF-5 or (b) rhBMP-2, respectively. Uncoated grafts served as controls. After 3 and 8 weeks, dissected blocks were prepared for immunohistochemical [osteocalcin (OC)] and histomorphometrical analysis [e.g. area (mm2) of new bone fill (BF), newly formed mineralized (MT) and non-mineralized tissue (NMT)]. Results: rhBMP-2 biocoated BOG revealed significantly highest BF and MT values at 3 (upper and lower jaws , UJ/LJ , compared with BOG) and 8 weeks (UJ , compared with rhGDF-5). Biocoating of BOB using both rhGDF-5 and rhBMP-2 resulted in significantly increased MT values at 8 weeks (UJ/LJ , compared with BOB). In all groups, NMT adjacent to BOG and BOB scaffolds revealed pronounced signs of an OC antigen reactivity. Conclusions: Within the limits of the present study, it was concluded that both rhGDF-5 and rhBMP-2 have shown efficacy; however, their bone regenerative effect was markedly influenced by the carrier. [source] Immunohistochemical characterization of guided bone regeneration at a dehiscence-type defect using different barrier membranes: an experimental study in dogsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2008Frank Schwarz Abstract Objectives: The aim of the present study was to evaluate immunohistochemically the pattern of guided bone regeneration (GBR) using different types of barrier membranes. Material and methods: Standardized buccal dehiscence defects were surgically created following implant bed preparation in 12 beagle dogs. Defects were randomly assigned to six different GBR procedures: a collagen-coated bone grafting material (BOC) in combination with either a native, three cross-linked, a titanium-reinforced collagen membrane, or expanded polytetrafluorethylene (ePTFE), or BOC alone. After 1, 2, 4, 6, 9, and 12 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin , OC, transglutaminase II , angiogenesis) and histomorphometrical analysis [e.g., bone-to-implant contact (BIC), area of new bone fill (BF)]. Results: In general, angiogenesis, OC antigen reactivity, and new bone formation mainly arose from open bone marrow spaces at the bottom of the defect and invaded the dehiscence areas along the implant surface and BOC. At 4 weeks, membranes supporting an early transmembraneous angiogenesis also exhibited some localized peripheral areas of new bone formation. However, significantly increasing BIC and BF values over time were observed in all groups. Membrane exposure after 10,12 weeks was associated with a loss of the supporting alveolar bone in the ePTFE group. Conclusion: Within the limits of the present study, it was concluded that (i) angiogenesis plays a crucial role in GBR and (ii) all membranes investigated supported bone regeneration on an equivalent level. [source] | ||||||||||