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To identify activated T cell subset in the asthmatic bronchia, we developed a triple-colour immunohistofluorescence labelling technique on cryo-section to discriminate activated CD4+ CD25+ T cells, (effector T cells) from Foxp3+ regulatory T cells ( Treg). Additional coexpression of activation and proliferation markers was also examined in situ. Bronchial biopsies were taken from 20 aluminium potroom workers (12 smokers) with asthma (>12% reversibility), 15 non-asthmatic potroom workers (7 smokers) and 10 non-smoking, non-exposed controls. Non-smoking asthmatics had significantly higher subepithelial density of both Tregs, effector T cells, activated ( HLA- DR+) CD8+ and activated CD4+ T cells. Moreover, both Tregs, effector T cells and CD8+ T cells proliferated in the non-smoking asthmatics, only. Although smoking asthmatics had no asthma-associated increase in bronchial T cell, both had a significantly increase in effector T cell to Treg ratios. The significantly increased bronchial density of Tregs, effector T cells, proliferative T cells and activated CD8+ T cells in non-smoking asthmatics clearly showed that both the effector T cells and the inhibitory Treg system were activated in asthma. [ABSTRACT FROM AUTHOR]

It has been suggested that epithelial cyclooxygenase-2 (COX-2) promotes oral carcinogenesis and carcinoma malignancy through increased prostaglandin E(2) (PGE(2)) production. Although oral squamous cell carcinomas (OSCC) often express COX-2, they may also produce PGE(2) in a COX-1-dependent manner. We used 6 isolated cell lines to investigate which COX isoforms OSCC may use for PGE(2) production. COX-1 and -2 expression patterns divided the 6 OSCC cell lines into 3 distinct groups: both COX isoforms low, only COX-1 high, or both COX isoforms high. Multicolor immunohistofluorescence staining confirmed the COX-expression profiles in organotypic 3D cultures and the COX-2 dominance in OSCC tumors. Epidermal growth factor (EGF) stimulation induced COX-2 (but not COX-1) expression and increased PGE(2) production, which was attenuated by COX-2 (but not COX-1) specific inhibition or siRNA-mediated COX-2 gene knockdown. Thus, PGE(2) production in OSCC cell lines was COX-2-dependent. [ABSTRACT FROM AUTHOR]

It has been suggested that epithelial cyclooxygenase- 2 (COX-2) promotes oral carcinogenesis and carcinoma malignancy through increased prostaglandin E2 (PGE2) production. Although oral squamous cell carcinomas (OSCC) often express COX-2, they may also produce PGE2 in a COX-1-dependent manner. We used 6 isolated cell lines to investigate which COX isoforms OSCC may use for PGE2 production. COX-1 and -2 expression patterns divided the 6 OSCC cell lines into 3 distinct groups: both COX isoforms low, only COX-1 high, or both COX isoforms high. Multicolor immunohistofluorescence staining confirmed the COX-expression profiles in organotypic 3D cultures and the COX-2 dominance in OSCC tumors. Epidermal growth factor (EGF) stimulation induced COX-2 (but not COX-1) expression and increased PGE2 production, which was attenuated by COX-2 (but not COX-1) specific inhibition or siRNA-mediated COX-2 gene knockdown. Thus, PGE2 production in OSCC cell lines was COX-2- dependent. Abbreviations: COX, cyclooxygenase; EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; NSAID, non-steroidal antiinflammatory drug; OSCC, oral squamous cell carcinoma; PG, prostaglandin; PGE2, prostaglandin E2; and PGES, prostaglandin E2 synthase. [ABSTRACT FROM AUTHOR]

The specialized M cells in the follicle-associated epithelium (FAE) of Peyer's patches (PP) represent an intimate interphase between luminal antigens and gut-associated lymphoid tissue (GALT). M cells form pockets that contain clusters of leucocytes probably involved in the first encounter with antigens from the gut lumen. Three-colour immunofluorescence in situ phenotyping of these leucocytes in humans revealed about equal numbers of B (CD19/20+) and T (CD3+) lymphocytes, the latter mainly CD4 + (median 73%, range 40-90%), but relatively few macrophages (CD68+). Most B cells (90%) were positive for surface IgM (sIgM) and often co-expressed sIgD (median 34%, range 6-60%). Occasional B cells (median 2%) did not express CD45RA (range 0-15%) and 13% virtually lacked HLA-DR (range 0-40%). Some B and T lymphocytes expressed the nuclear proliferation marker Ki-67 (range 1-10%). The M-cell pockets also contained occasional cells with cytoplasmic lgA or IgM. These sites thus contained a heterogeneous B-cell population with features of both follicular mantle (sIgD+ sIgM+) and marginal zone (sIgD- sIgM+) B lymphocytes. Adjacent T lymphocytes were generally of the memory phenotype (CD45RO+). Our findings suggest that the M-cell-associated B lymphocytes represent local extensions of B-cell follicles towards the gut lumen, developed topically to facilitate antigen presentation and diversification of mucosal immune responses. [ABSTRACT FROM AUTHOR]

Follicular dendritic cells (FDC) present in germinal centres trap considerable amounts of C3- containing immune complexes (IC). Activation of the terminal pathway of complement (C) on biological membranes normally generates C5b-9(m), which is the membranolytic form of the terminal complement complex (TCC). By contrast, when C activation takes place in the extracellular fluid phase, S-protein binds to C5b-7 and the non-lytic soluble SC5b-9 is formed. In this study deposits of C3d, C5, C9 TCC neocpitope and S-protein were demonstrated by immunohisto- chemistry on FDC in human tonsils, lymph nodes, spleens, appendices and colonic mucosae. TCC and S-protein were likewise observed on FDC in imprints from tonsils. The identical spatial distribution revealed by paired staining suggested that TCC had been generated in situ. The staining intensity for TCC and S-protein varied in parallel, which suggested that the S-protein may be incorporated in the membrane-bound TCC-perhaps rendering it non-lytic. However, the actual mechanism and function of the observed TCC and associated S-protein deposition needs further elucidation. [ABSTRACT FROM AUTHOR]

Expression of the γ/δ T cell receptor (TCR) on CD3+ intraepithelial lymphocytes (IELs) was studied by two-colour immunofluorescence in duodenal tissue sections from healthy (n = 6) or infection-prone (n=7) subjects with selective IgA deficiency (IgAD), and subjects (n = 4) with combined IgAD and IgG subclass deficiency. TCRγ/δ+ IEL proportions in selective IgAD subjects (median 6.3%, range 1.0-41%.) and in those with combined deficiency (median 4.5%, range 1.2-33%) were well within the range (0.3-38%) for histologically normal controls (n=11), but the healthy IgAD subgroup tended to show raised TCRγ/δ+ IEL proportions (median 13.6%) compared with the other two subgroups. Also the number of TCRγ/δ+ IELs per intestinal length unit was relatively high (median 13.9/mm) in the healthy IgAD subjects, and significantly raised (P<0.03) compared with controls (median .12 'mm). Paired staining revealed that most TCRγ/δ+ IELs in both selective IgAD (98%) and combined deficiency (99%) were CD8-, and a large fraction (median 84% and 63%, respectively) expressed the Vδ1/Jδl-encoded epitope. The total number of CD3+ IELs (mostly CD8+) was similar to controls. IgAD subjects, and especially the healthy subgroup, had significantly increased serum concentrations of soluble CD8 (P<0.0002). neopterin (P<0.005), and β2-microglobulin (P<0.007), which was similar to our previous observations in common variable immunodeficiency, and probably reflected stimulation of cell-mediated immunity. In addition, the increased TCRγ/δ+ IELs might reflect a component of compensatory surface protection in the healthy IgAD subgroup. [ABSTRACT FROM AUTHOR]

It has been assumed that S-protein (vitronectin) associates with terminal C5b-9 complement complexes only when the latter fail to attach to target lipid bilayers, thereby forming inactive fluidphase SC5b-9 complexes. Using monoclonal anti-S-protein antibodies, we show here that a minor portion of C5b-9 complexes associated with both homologous and heterologous cells contain S-protein. This conclusion derives from Western blot analyses, from the sedimentation behaviour of solubilized S-protein, and from the fad that the protein co-immunoprecipitates with C5b-9(m). Association of S-protein with C5b-9(m) takes place primarily al the stage of C9-binding. An average of &les;0.4 moles of S-protein are estimated to be present per mole C5b-9(m). Hence, only a fraction of C5b-9 complexes contain S-protein. The function of cell-bound S-protein is unknown. Haemolytic titrations with purified components failed to demonstrate any protective effect of S-protein on the lysis of sheep or human erythrocytes by C5b-9. S-protein bound to complement-lysed homologous or heterotogous cells is readily detectable by conventional immunocytochemical staining. We conclude that differentiation between tissue-deposited fluid-phase C5b-9 and membrane C5b-9 complexes cannot be made on the basis of immunohistological stainings for S-protein alone. [ABSTRACT FROM AUTHOR]