Host defense mechanisms against Salmonella infection

Interaction between endometrial epithelial cells and blood leucocytes promotes cytokine release and epithelial barrier function in response to Chlamydia trachomatis lipopolysaccharide stimulation

Chlamydia trachomatis infection is currently the most common cause of infection-related sterility in women. However, it remains largely unknown how uterine epithelial cells interact with recruited leucocytes in response to C. trachomatis infection in the female genital tract. To study the defence mechanism of the endometrium against C. trachomatis infection, we established an in vitro co-culture of EEC (endometrial epithelial cells) and PBL (peripheral blood leucocytes) isolated from mice and investigated the immune response of these cells upon C. trachomatis LPS (lipopolysaccharide) challenge using a cytokine antibody array and RT-PCR (reverse transcription-PCR). Our results showed that upon C. trachomatis LPS stimulation, proinflammatory cytokines/chemokines, such as TNF-alpha, IL-1beta, MIPs (macrophage inflammatory proteins), IL-12p40p70, KC, GCSFs (granulocyte colony stimulating factors), IL-6 and TIMPs (tissue inhibition metalloproteinases) are up-regulated and/or released from EEC-PBL co-culture. Further, the TER (transepithelial resistance), measured by the Isc (short-circuit current) technique was significantly increased in EEC/PBL co-cultured cells and also when stimulated with C. trachomatis LPS compared with EEC alone. These changes appear to be mediated by the change in cytokine-induced expression of tight junction-related protein ZO-1. The present results demonstrated that the epithelial-immune cross-talk could promote the release of proinflammatory cytokines and enhance the barrier function of the endometrium against C. trachomatis infection in the female reproductive tract.

Effects of in-feed egg yolk antibodies on Salmonella shedding, bacterial antibiotic resistance, and health of pigs

To determine effects of anti-Salmonella egg yolk antibodies on shedding and antibiotic resistance of Salmonella enterica Typhimurium, newly weaned pigs were randomly assigned to six dietary treatments. These treatment groups were (i) a control (basal) diet without additives and similar diets with (ii) egg yolk powder derived from chickens challenged with Salmonella Typhimurium antigens, (iii) a commercial egg yolk powder control, (iv) apramycin for 14 days followed by carbadox, (v) oxytetracycline, or (vi) spray-dried plasma protein. Treatments were provided beginning on day 3 of the trial, and all pigs were challenged with 5 ml of 10(8) CFU/ml Salmonella Typhimurium on day 7. Fecal samples were collected on days 0, 7, 8, 12, 14, 21, 58, 88, and 118 for isolation of Salmonella and Escherichia coli to determine shedding and antibiotic resistance patterns. Body weights, white blood cell counts, and plasma concentrations of anti-Salmonella immunoglobulin G and porcine interleukin 1beta were analyzed as indicators of animal health. The percentage of pigs shedding Salmonella was lower for antibiotic treatment groups compared with other groups; however, resistance was greater in E. coli from pigs fed antibiotics than in pigs in other treatment groups. Health and performance indicators (pig weight gains, white blood cell counts, and plasma concentrations of anti-Salmonella antibodies) did not differ between treatment groups. These studies indicate that feeding egg yolk containing anti-Salmonella immunoglobulin Y may not be effective in controlling shedding of Salmonella in pigs.