concanavalin-a and Intestinal-Diseases--Parasitic

High levels of protection can be attained against Haemonchus contortus challenge infection in sheep using native antigens isolated from the gut of the adult parasite. However, vaccination with recombinant forms of these antigens, or components thereof, has disappointingly failed to generate similar levels of protection, suggesting that appropriate nematode glycosylation may be a prerequisite for protection. The free-living nematode, Caenorhabditis elegans is closely related to H. contortus and has been shown to share similar glycan moieties. In order to investigate the potentially protective role of these glycan moieties, a complex set of glycoproteins was isolated from C. elegans using ConA-lectin chromatography and their efficacy as immunogens against H. contortus challenge infection evaluated in sheep. Despite the generation of a high titre systemic IgG antibody response to the C. elegans glycoproteins and the ability of these antibodies to bind to the microvillar surface of the gut of H. contortus, no protection against challenge infection was observed. Serum antibodies to the C. elegans glycoproteins cross-reacted with the H. contortus host-protective antigen, H-gal-GP, by ELISA, although the level of cross-reactivity was not of a magnitude considered protective. Qualitative differences were also determined between the glycan epitopes of the C. elegans ConA-binding proteins and those of H-gal-GP, suggesting the presence of H. contortus-specific patterns of glycosylation.

Topics: Animals; Antibodies, Helminth; Caenorhabditis elegans Proteins; Concanavalin A; Enzyme-Linked Immunosorbent Assay; Epitopes; Glycosylation; Haemonchiasis; Haemonchus; Immunoglobulin G; Intestinal Diseases, Parasitic; Protein Binding; Sheep; Sheep Diseases; Vaccines

Precursors of mast cells were defined as cells that formed mast-cell colonies in methylcellulose culture (CFU-mast). Mononuclear cells (MNC) were obtained from the bone marrow, peripheral blood, and small intestine of Ws/Ws rats with a small deletion at the tyrosine kinase domain of c-kit and of control normal (+/+) rats. In the culture containing concanavalin A-stimulated spleen cell conditioned medium (ConA-SCM) alone, the numbers of mast-cell colonies produced by Ws/Ws MNC were comparable with those of +/+ MNC. In the culture containing both ConA-SCM and stem cell factor (a ligand of c-kit), however, the numbers of mast-cell colonies produced by +/+ blood MNC were 107 times as great as that of Ws/Ws blood MNC. Using this culture condition, we investigated changes in concentration of CFU-mast in the marrow, blood, and intestine of +/+ rats after infection with Nippostrongylus brasiliensis (NB), which induced marked mast-cell accumulation in the small intestine. The concentration of CFU-mast in blood dropped to 21% of preinfection levels 1 week after the NB infection. In contrast, a sevenfold increase of CFU-mast occurred in the small intestine. The proportion of CFU-mast in S phase of the cell cycle remained at low levels in the marrow and blood after NB infection, but it increased significantly in the small intestine. The present result suggests that NB infection induces the invasion of CFU-mast into the intestine from blood and their subsequent proliferation in the tissue site.

Topics: Animals; Blood Cell Count; Bone Marrow; Cell Count; Cell Movement; Cells, Cultured; Concanavalin A; Culture Media, Conditioned; Hematopoietic Cell Growth Factors; Hematopoietic Stem Cells; Intestinal Diseases, Parasitic; Intestine, Small; Mast Cells; Nippostrongylus; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-kit; Rats; Rats, Inbred BN; Rats, Mutant Strains; Receptor Protein-Tyrosine Kinases; Receptors, Colony-Stimulating Factor; Sequence Deletion; Stem Cell Factor; Strongylida Infections; T-Lymphocytes

Jejunal longitudinal muscle from Trichinella-infected Sprague-Dawley rats generates increased tension in vitro 6 days after infection. To investigate the extent to which this increase is dependent on T lymphocytes, smooth muscle contraction was examined in athymic rats (rnu/rnu) and in their euthymic (rnu/+) littermates 6 days after infection. In both thymus-bearing and athymic rats, the highest concentrations of Trichinella were found in the jejunum where mucosal myeloperoxidase activity was increased. Muscle from infected euthymic rats generated more tension to carbachol or 5-hydroxytryptamine than that of noninfected controls. In contrast, there was no difference between the responses of muscle from infected and control athymic animals. However, when athymic rats were reconstituted with splenic mononuclear cells, increased tension to carbachol or 5-hydroxytryptamine was observed after infection. T-lymphocyte activity was demonstrated by in vitro assays in euthymic or reconstituted rats but not in athymic rats. It is concluded that some changes in intestinal smooth muscle function following Trichinella spiralis infection in the rat are T lymphocyte dependent. These results support the concept of immunomodulation of intestinal smooth muscle function.

Topics: Analysis of Variance; Animals; Carbachol; Cell Division; Concanavalin A; Disease Models, Animal; Intestinal Diseases, Parasitic; Intestinal Mucosa; Jejunum; Male; Muscle Contraction; Muscle, Smooth; Peroxidase; Rats; Rats, Inbred Strains; Rats, Nude; Serotonin; Spleen; T-Lymphocytes; Trichinellosis