Colitis/immunology; Colon/immunology; Immunity, Innate; Macrophage Activation; Macrophages/immunology; Receptors, Immunologic/metabolism; Adolescent; Adoptive Transfer; Animals; Antigens, CD/analysis; Biopsy; Case-Control Studies; Child; Child, Preschool; Colitis/chemically induced; Colitis/genetics; Colitis/pathology; Colon/pathology; Cytokines/metabolism; Dextran Sulfate; Disease Models, Animal; Escherichia coli/pathogenicity; Female; Humans; Inflammation Mediators/metabolism; Leukocyte Immunoglobulin-like Receptor B1; Macrophages/microbiology; Macrophages/transplantation; Male; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Mitogen-Activated Protein Kinases/metabolism; NF-kappa B/metabolism; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 11/metabolism; Protein Tyrosine Phosphatase, Non-Receptor Type 6/metabolism; Receptors, Cell Surface/analysis; Receptors, Immunologic/analysis; Receptors, Immunologic/deficiency; Receptors, Immunologic/genetics; Time Factors