Two human mast cell types were identified by immunohistochemical techniques in skin, lung, and small intestine. One type contains the neutral proteases, tryptase and chymotryptic proteinase, and is termed the TC mast cell. The second type contains only tryptase and is termed the T mast cell. Both types are fixed better by Carnoy's fluid than by formalin. (4,5,(9)(10)(11).The presence of distinct chymotryptic neutral proteases in rat mucosal and connective tissue mast cells is a useful criterion for designation of a rat mast cell to a particular type (12, 13). For example, the finding of rat mucosal mast cell chymotryptic protease in a tumor cell line previously considered to be a rat basophil leukemia tumor (RBL-1) indicated that this tumor may be a rat mucosal mast cell leukemia tumor (14). In dispersed human lung mast cells, the major neutral protease is tryptase (15-17). Tryptase is a specific marker for all mast cells in human lung, small bowel, and skin (17-19), including formalin-fixable and -nonfixable mast cells. A second neutral protease, termed human skin chymotryptic proteinase, has been purified from skin (20) and localized to mast cells in skin and lung (21,22). The present study uses murine monoclonal anti-tryptase and affinity-purified rabbit polyclonal anti-skin chymotryptic proteinase antibodies in a double indirect immunoenzymatic technique to demonstrate two mast cell types in human skin, lung, and small bowel, based on distinct protease compositions. MATERIALS AND METHODSMaterials. Peroxidase-conjugated goat anti-rabbit IgG (Cooper Biomedical, Malvern, PA), alkaline phosphataseconjugated goat anti-mouse IgG (Boehringer Mannheim), peroxidase-conjugated goat anti-mouse IgG (Bio-Rad), 3,3-diaminobenzidine tetrahydrochloride (Electron Microscopy Sciences, Fort Washington, PA), 30% H202 (Fisher), and naphthol AS-MX phosphoric acid and fast blue RR (Sigma) were obtained as indicated. Murine monoclonal IgG2b,K anti-tryptase, termed G5 (anti-T), and a negative control IgG2b,K, termed MPC-11 (17), as well as polyclonal rabbit IgG anti-human skin chymotryptic proteinase, termed C8 (anti-C), and IgG from nonimmunized rabbits (21) were purified as described previously. Fresh surgical or autopsy tissues were fixed in Carnoy's fluid (60% methanol/30% chloroform/10% glacial acetic acid) or in neutral buffered formalin (10% formalin in 0.08 M sodium phosphate, pH 7.4) and 5-,gm-thick sections were prepared. Macroscopically normal appearing areas of skin, lung, and small bowel were used. In addition, mast cells were enzymatically dispersed from human lung and cytocentrifuge preparations were obtained as described (17).Single Indirect Immunohistochemistry. Fixed sections were dewaxed in xylene over three 5-min periods. Endogenous peroxidase was blocked with 0.6% H202 in methanol for 30 min at 22°C. Rehydration was performed with graded ethanol solutions (100%, 95%, 80%, 70%, 50%) and H20, each for a 3-min period. Nonspecific staining was reduced by incubation with 10% heat-inactivated normal goat seru...

The mechanisms whereby human glial cells modulate local immune responses are not fully understood. Interleukin-27 (IL-27), a pleiotropic cytokine, has been shown to dampen the severity of experimental autoimmune encephalomyelitis, but it is still unresolved whether IL-27 plays a role in the human disease multiple sclerosis (MS). IL-27 contribution to local modulation of immune responses in the brain of MS patients was investigated. The expression of IL-27 subunits (EBI3 and p28) and its cognate receptor IL-27R (the gp130 and TCCR chains) was elevated within post-mortem MS brain lesions compared with normal control brains. Moreover, astrocytes (GFAP(+) cells) as well as microglia and macrophages (Iba1(+) cells) were important sources of IL-27. Brain-infiltrating CD4 and CD8 T lymphocytes expressed the IL-27R specific chain (TCCR) implying that these cells could respond to local IL-27 sources. In primary cultures of human astrocytes inflammatory cytokines increased IL-27 production, whereas myeloid cell inflammatory M1 polarization and inflammatory cytokines enhanced IL-27 expression in microglia and macrophages. Astrocytes in postmortem tissues and in vitro expressed IL-27R. Moreover, IL-27 triggered the phosphorylation of the transcription regulator STAT1, but not STAT3 in human astrocytes; indeed IL-27 up-regulated MHC class I expression on astrocytes in a STAT1-dependent manner. These findings demonstrated that IL-27 and its receptor were elevated in MS lesions and that local IL-27 can modulate immune properties of astrocytes and infiltrating immune cells. Thus, therapeutic strategies targeting IL-27 may influence not only peripheral but also local inflammatory responses within the brain of MS patients.

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We undertook studies in the isolated perfused rat lung to determine 1) the effects of endothelial charge neutralization with the polycation protamine sulfate on microvascular permeability, lung water, and anionic ferritin binding to the endothelium and 2) the role of heparan sulfate and hyaluronate, negatively charged cell surface glycosaminoglycans, on permeability. Capillary permeability was determined by tissue 125I-albumin accumulation in isolated perfused rat lungs. In control lungs the 5-min albumin uptake was 0.50 +/- 0.05 cm3.s-1.g dry tissue-1 X 10(-3). It was increased by 132 +/- 7.8% (P less than 0.001) by protamine (0.08 mg/ml) and 65 +/- 12% (P less than 0.01) by heparinase (5 U/ml), whereas hyaluronidase (25 NFU/ml) was without effect. In control lungs total water was 4.83 +/- 0.15 ml g/dry tissue. Protamine increased lung water 12 +/- 2% (P less than 0.05). Heparinase caused a 9 +/- 3% increase (P less than 0.05), and hyaluronidase had no effect. Electron microscopy demonstrated that protamine increased anionic ferritin binding to the surface of endothelial cells. We conclude that protamine sulfate neutralization of negative charge in the pulmonary microcirculation leads to increased microvascular permeability. Heparin sulfate may be responsible for this charge effect.