Human Intestinal Cell Line Int-407 Research Articles

Surfactant protein-D attenuates the lipopolysaccharide-induced inflammation in human intestinal cells overexpressing toll-like receptor 4.

Necrotizing enterocolitis (NEC) is a devastating inflammatory disease of preterm infants that may depend on overexpression of toll-like receptor-4 (TLR4) in the immature intestine. Surfactant protein (SP)-D is a member of the collectin family and plays an important role in innate immunity, particularly in the airways. Although SP-D also exists in the intestines, little is known about its function. This study investigated whether SP-D can attenuate the inflammatory response of TLR4-overexpressing embryonal intestinal cells. All experimental procedures were performed using the human intestinal cell line INT407 originally derived from human embryonal intestines. Platelet-activating factor (PAF), reported to be elevated in NEC patients, was used to induce TLR4 overexpression in the human embryonal intestinal cell line INT407. TLR4 expression was measured using quantitative real-time PCR. Inflammatory responses to PAF (5µM), the TLR4 agonist lipopolysaccharide (LPS, 100ng/ml), PAF+LPS, and PAF+LPS following SP-D pretreatment (20µg/ml) were assessed by enzyme-linked immunosorbent assay (ELISA) of interleukin-8 (IL-8) release (in pg/ml). Expression of TLR4 mRNA (mean±SD) was upregulated by PAF (369%±28%, p<0.001). Stimulation with PAF+LPS resulted in higher IL-8 release (1959.3±52.3) than control (141.2±12.4), LPS (167.3±65.8), or PAF (1527.2±129.4) treatment (p<0.05). Release in response to PAF+LPS (1590.1±319.3) was attenuated by SP-D pretreatment (1161.6±131.6; p<0.05). SP-D attenuates LPS-induced IL-8 production in TLR4-overexpressing intestinal cells, suggesting that SP-D may have a protective effect in the development of NEC in preterm infants.

Antagonistic activity against Salmonella infection in vitro and in vivo for two Lactobacillus strains from swine and poultry

In this study, we isolated two lactobacillus strains, i.e., strain LAP5 and LF33, from swine and poultry, respectively, and showed that both strains were acid as well as bile tolerant and were able to adhere to the cultured human intestinal cell lines, such as Int-407 and Caco-2 cells, and to the intestinal epithelium cells isolated from swine, poultry and mouse (BALB/c). Both of these LAB strains were shown to inhibit the growth of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus cereus. When these two LAB strains were evaluated for their antagonistic activity against Salmonella ( S. typhimurium) invasion to cultured human intestinal cell line Int-407 and to mouse (BALB/c) liver and spleen, these two LAB strains were found to have significant antagonistic effect.

Presence of immunoreactive adrenomedullin in human and bovine milk

We examined by radioimmunoassay the presence of immunoreactive adrenomedullin (ir-AM) in human and bovine milk. Milk samples displaced 125I-AM from the AM-antiserum in parallel to the standard curve. RP-HPLC revealed a main immunoreactive peak eluting as synthetic AM. Concentrations in human milk ranged between 140 and 404 pg/mL. In cow, the levels of AM were 73.5 ± 3.8 pg/mL. Bovine milk products had AM levels similar to those found in fresh bovine milk. Human milk had growth promoting activity on the human intestinal cell line Int-407 that could be partially blocked with an anti-AM antibody.