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Background: There is little information about the involvement of galectin-9 (Gal-9) in allergic inflammation. Thus, we investigated the role of Gal-9 in asthma model guinea pigs. Methods: Airway resistance (Raw) was measured using a double-flow plethysmograph system. Gal-9 expression in the lung was assessed by Western blot and immunohistochemistry. Eosinophil chemotactic activity was evaluated in a chamber containing a polyvinylpyrolidone-free membrane. Cell apoptosis was analyzed on a flowcytometry with propidium iodide. Results: In cloning guinea pig Gal-9 we identified three isoforms that differ only in the length of their linker peptides, just as with human Gal-9. Guinea pig Gal-9 was found to be a chemoattractant for eosinophils and to promote induction of apoptosis in sensitized but not non-sensitized T lymphocytes. In allergic airway hypersensitivity model, a low level of Gal-9 expression was observed in the nonsensitized/nonchallenged group, but upregulation was detected at 7 h after challenge and sustained up to 24 h. Such upregulation correlated with elevation of eosinophil peroxidase activity but not with increased Raw. Conclusions: The present results provide evidence that Gal-9 is not involved in airway hypersensitivity, but is partly involved in prolonged eosinophil accumulation in the lung.

Background: Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for blood monocytes in vitro. Recent studies in MCP-1-transgenic mice revealed that the local production of MCP-1 caused monocyte infiltration. However, the kinetics of monocyte infiltration after the production of MCP-1 or the amount of MCP-1 necessary for monocyte recruitment are not known. Methods: We purified recombinant rat MCP-1 expressed in COS-7 cells, and injected it into rat skin. The infiltrating cells were examined by immunohistochemistry and ultrastructural peroxidase cytochemistry. Results: Rat recombinant MCP-1 had a molecular mass of approximately 30 kD and exhibited the peak monocyte chemotactic activity at 10–9 M. One microgram of MCP-1 caused intra- and extravascular accumulation of mononuclear cells 3 h after injection. The cells were ED1+, indicating they were blood monocytes. The infiltration of mononuclear cells peaked at 12–24 h, and most of them were TRPM-3+ and ED3+, characteristic to exudate macrophages. None of the cells expressed ED2 or Ki-M2R antigens, markers for resident macrophages, until 3 days after injection. There was no uptake of [3H]thymidine by the infiltrating cells. Ultrastructural peroxidase cytochemistry confirmed that the infiltrating cells were monocytes and exudate macrophages. The number of OX8+ lymphocytes also peaked at 12 h, consisting of approximately 9% of the total infiltrating cells. Conclusion: These results indicate that MCP-1 attracts blood monocytes as early as 3 h and the infiltrating monocytes differentiate into exudate macrophages in loco. However, this effect was transient and the infiltration of monocytes did not result in tissue damage.

Background: CXC chemokines, IL–8 and GRO, play a role in the recruitment of neutrophils in the human. The functional orthologues in the rat and mouse are CINC/KC and MIP–2. The lack of IL–8 made these animals less useful to study the role of IL–8 and GRO. Methods: Guinea pig (gp) cDNA libraries were screened for GRO and IL–1β. A gp genomic library was screened with a gpGRO cDNA probe. Expression of gpIL–8, gpGRO, gpTNFα, and gpIL–1β was investigated by Northern analysis and/or by in situ hybridization. Results: Two gpGRO cDNAs, a 3.0–kb gpGRO genomic DNA, and a gpIL–1β cDNA were cloned. gpGRO and gpIL–8 mRNA were detected in different tissues including lungs 1 h after intraperitoneal injection of lipopolysaccharide (LPS) into guinea pigs. gpGRO, gpIL–8, gpTNFα, and gpIL–1β expression peaked at 3 h in the lungs. Both gpGRO and gpIL–8 mRNA were detected in the cells in alveolar spaces and bronchial epithelial cells. However, gpGRO mRNA, but not gpIL–8, was also expressed in endothelial cells and vascular smooth muscle cells. Conclusions: gpGRO and gpIL–8 mRNA rapidly accumulated in the lungs of guinea pigs after LPS injection. Expression of gpIL–8 and gpGRO mRNA appeared to be independent from TNFα– or IL–1β–stimulation in this model. A high level expression of gpGRO in vascular cells suggest an important role of GRO in the sequestration of neutrophils and multi–organ injuries induced by LPS. The guinea pig will provide an excellent model to study the roles of IL–8 and GRO, important inflammatory mediators in the human.

In complement-depleted condition induced by cobra venom factor (CoF), tissue macrophage reaction and macrophage chemotactic activity (MCA) in skin extract from skin lesions induced by DNP-Ascaris extract (DNP-As) were decreased, respectively. MCA in the fraction containing macrophage chemotactic factor b (B fraction) was decreased completely. While MCA in the fraction containing macrophage chemotactic factor a and c (A fraction) was affected only slightly. These results suggested that the decrease of MCA of Infraction might be associated with depletion of complement system by CoF. Using anti-C5 antibody, it was confirmed that macrophage chemotactic factor-b (MCF-b) (MW 14,000: thermostable) might be derived from C5 fragment in vivo.