Browsing by Subject "antibody"
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Item Cellular requirements for antibody production in a novel LPS-enhanced model of autoimmune myasthenia gravis(2009-07-20) Windy Rose Allman; Premkumar Christadoss, M.D.; Stephen Higgs, Ph.D.; Socrates Tzartos, Ph.D.; Silvia Pierangali, Ph.D.; Gary Klimpel, Ph.D.Bacterial lipopolysaccharide (LPS) is a T cell-independent adjuvant known to abrogate peripheral tolerance. For the first time, the potential of LPS to induce antigenspecific B cell responses to acetylcholine receptor (AChR) in myasthenia gravis (MG) was evaluated in wild type (WT), CD4-/-, and CD8-/- C57BL/6 mice. Historically, MG\r\nhas been induced in mice by immunization with AChR emulsified in complete Freund’s\r\nadjuvant (CFA). WT mice immunized with AChR in LPS developed an MG-like disease\r\n(LPS-EAMG) similar to a disease induced by immunization with AChR in complete\r\nFreund’s adjuvant (CFA-EAMG). The CD4-/- mice were resistant to the development of\r\nCFA-EAMG, but had significantly higher frequencies of IgG expressing AChR-binding\r\nB cells than WT mice. However, CFA-AChR immunization of CD4-/- mice failed to\r\ndifferentiate these cells to secrete anti-AChR IgG. The CD4-/- mice were susceptible to\r\nthe development of LPS-EAMG and also had significantly higher frequencies of IgG\r\nexpressing AChR-binding B cells than WT mice. WT and CD4-/- mice in the LPSEAMG\r\nmodel had significant amounts of secreted high-affinity anti-AChR IgG2,\r\nimmune complex deposits (IgG, C3, MAC) in muscle, and elevated sera levels of the Bcell survival factor, BAFF. Our results indicate that LPS abrogated B cell differentiation\r\nto antibody secreting cells in the LPS-EAMG model. Furthermore, CD8-/- mice were\r\nalso susceptible to the development of LPS-EAMG, but were resistant to the development of moderate or severe signs of EAMG. While CD8 deficiency did not affect the quantity or avidity of secreted anti-AChR antibodies, it significantly reduced the\r\nsurvival of circulating IgG expressing AChR-binding B cells. The findings, accordingly\r\nhave allowed us to identify an alternate cellular mechanism for the development of EAMG.Item The Effects of Probiotic and Eimeria on Gut Morphology and Humoral Immunity in Broilers(2012-02-14) Horrocks, Sadie LynCoccidiosis has a negative economic impact on the commercial poultry industry, and probiotics are beneficial bacteria that aid in maintaining healthy gut microflora. We hypothesized that probiotic administration would positively affect gut morphology and increase IgG secretion during an Eimeria challenge, which was evaluated by measuring total chicken IgG and gut morphology (villus height, villus width, villus surface area, crypt depth, villus height to crypt depth ratio and lamina propria thickness). On day-of-hatch, broilers were placed into floor pens with 50 percent pine shavings and 50 percent used litter. The broilers were exposed to Eimeria oocysts via the feed on day 14 and challenged on day 36. On days 6, 22, 36, and 43, tissue samples from the intestine were collected for morphological evaluation, and blood samples were taken to quantify chicken IgG from serum. Data were measured using a factorial ANOVA and main effect means were deemed significant at P ? 0.05. In cases where significant interactions were observed, data was subjected to a one-way ANOVA. All means were separated using a Duncan?s Multiple Range Test. On day 6 in the duodenum, a significant interaction was observed regarding vaccination and probiotic administration (Coccivac?-B, Intervet/Schlering-Plough Animal Health/Merck and Co., Inc., Whitehouse Station, NJ). Villus height to crypt depth ratio decreased in ionophore treated birds compared to control birds in the duodenum and lower ileum on day 6, 36, and 43. Villus crypt depth in vaccinated birds decreased in the duodenum after the challenge. On day 43, the ionophore treated birds had less villus height and surface area compared to control and vaccinated birds, while lamina propria thickness increased in the duodenum, and non probiotic birds had longer villi than probiotic birds. On day 22, vaccinated birds had significantly increased chicken IgG levels compared to the control and ionophore birds, and the non probiotic birds had significantly increased IgG secretion compared to probiotic fed birds. On day 36, the ionophore birds had significantly increased levels of IgG compared to the control birds, which could also support that the ionophore delayed exposure to the parasite. These results suggest that gut morphology and humoral immunity are affected by probiotic administration, coccidiosis vaccination, ionophore application and Eimeria challenge. Both the day 43 morphology results and day 36 chicken IgG results for the ionophore treated birds demonstrates that ionophore administration delays exposure of the avian gut to invasive coccidia. More research is necessary to evaluate how probiotics influence coccidiosis vaccination and humoral immunity, so that probiotics may be used to improve the effectiveness of coccidiosis vaccination and to evaluate if probiotics aid in ameliorating the effects of an Eimeria infection.