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Maternal Transmission of Peanut Allergy Susceptibility Is Associated with IL-4 Promoter Demethylation in Offspring
AB218 Abstracts
777
Maternal Transmission of Peanut Allergy Susceptibility Is Associated with IL-4 Promoter Demethylation in Offspring Ying Song, MD, Ching-feng Huang, ChangDa Liu, Paul Faybusovich, Jia Chen, PhD, Xiu-Min Li, MD; Mount Sinai School of Medicine, New York, NY. RATIONALE: Maternal allergy is believed to be a risk factor for development of peanut allergy (PNA) in children, but there is no experimental evidence verifying maternal transmission of PNA susceptibility, and possible mechanisms remain unclear. METHODS: Five-week-old offspring of PNA C3H/HeJ mothers (PNAM) were sensitized with 5mg peanut (PN) and 20mg cholera toxin for 4 weeks and challenged intragastrically with PN. Sensitized offspring of normal mothers served as control. Anaphylactic reactions, serum PNspecific IgE, and splenocyte (SPC) and mesenteric lymph node (MLN) cell production of IFN-g, IL-4, IL-5, IL-10, and IL-17 were determined. In addition, CpG methylation of the IL-4 promoter in offspring’s MLN cells was determined by pyrosequencing. RESULTS: Offspring of PNA-M exhibited significant higher PN-IgE levels at week 4, higher symptom score and lower core body temperature post challenge compared to offspring of normal mothers. SPC and MLN cells from offspring of PNA-M produced significantly more Th2 cytokines and less Th1 cytokines than cells from offspring of normal mothers. Reduced methylation at IL-4 promoter at CpG-393 and CpG-408 in MLN cells was also found in offspring of PNA-M. CONCLUSIONS: The predisposition of PNA-M offspring to produce high levels of Th2 cytokines along with a hyper PN-IgE response to active PN sensitization and strong anaphylactic reactions is associated with hypo DNA methylation at IL-4 gene promoter.
778
TUESDAY
Oral Sensitization to Peanut in Balb/c Mice Is Enhanced by Dietary Elimination of Soybean Components - towards a Better Mouse Model for Food Allergy Lisa Chang, BS1, Hugh A. Sampson, MD, FAAAAI2, Madhan Masilamani, PhD2; 1Mt. Sinai School of Medicine, New York, NY, 2Mount Sinai School of Medicine, New York, NY. RATIONALE: Food allergy research is hampered by a lack of proper animal models mimicing human food allergic responses. Laboratory mice are generally fed grain-based chow made with large amounts of soybeans. Soybeans are rich in immunomodulatory isoflavones. We tested the role of dietary soy-components in allergic sensitization to peanut in Balb/c mice. METHODS: Mice (5-10 per group) were fed regular chow or a soy-free diet for two generations. After weaning, mice were either maintained on the same diet or fed a diet containing genistein+daidzein, soy isoflavones, followed by weekly oral-sensitization with crude peanut extract (CPE) plus cholera toxin. Anaphylactic reactions to peanut were scored after peanut oral challenge at week-6 and intra-peritoneal challenge at week-7. Serum peanut-specific antibody levels were measured at week-6. RESULTS: Mice bred on a soy-free diet and sensitized and challenged with peanut showed significantly greater anaphylactic scores and peanutspecific antibodies than mice fed regular chow [mean score: 1.2 vs 0.33, _0.001; IgG15 28 vs 21; _0.01; mean Ab levels (mg/ml): IgE5 8 vs 0.5, p< p< _0.01, respectively]. Introduction of dietary isoflaIgG25 3.6 vs 1.5, p< vones to mice on a soy-free diet significantly suppressed anaphylactic scores and peanut-specific antibody levels compared to soy-free diet alone _0.01; mean Ab levels (mg/ml): IgE5 2.8 vs 8, [mean score: 0.35 vs 1.2, p< _0.05 and IgG25 0.7 vs 3.6, p< _0.001, _0.01, IgG15 15 vs 28, p< p< respectively]. CONCLUSIONS: Dietary elimination of soy components enhances peanut sensitization in Balb/c mice. This dietary manipulation may be a valuable tool to mimic human food allergy in murine models.
J ALLERGY CLIN IMMUNOL FEBRUARY 2013
779
Epicutaneous Sensitization Results in IgE-Dependent Intestinal Mast Cell Expansion and Food Anaphylaxis Raif Geha, MD1, Lisa Bartnikas, MD1, Michael Gurish2, Oliver Burton1, Sabine Leisten1, Erin Janssen1, Hans C. Oettgen, MD, PhD, FAAAAI1, Jacqueline Beaupre1, Christopher Lewis1, K. Frank Austen3, Stephanie Schulte2, Jason L. Hornick, MD, PhD2, Michiko K. Oyoshi, PhD1; 1 Boston Children’s Hospital, Boston, MA, 2Brigham and Women’s Hospital, MA, 3Brigham and Women’s Hospital/Harvard Medical School, Boston, MA. RATIONALE: Sensitization to food antigen may occur through cutaneous exposure. We tested whether epicutaneous (EC) sensitization with food antigen predisposes to IgE-mediated anaphylaxis upon oral allergen challenge. METHODS: BALB/c mice were EC sensitized by repeated application of ovalbumin (OVA) to tape-stripped skin over 7 weeks, or orally immunized with OVA and cholera toxin (CT) weekly for 8 weeks, then orally challenged with OVA. Body temperature and serum mouse mast cell protease 1 (mMCP-1) level was measured following challenge. Tissue mast cells (MCs) were examined by chloroacetate esterase staining. Serum OVA-specific IgE and IgG1 antibodies and splenocyte cytokine production were measured by ELISA. Serum interleukin-4 (IL-4) levels were measured using an in vivocytokine capture assay. RESULTS: EC sensitized mice exhibited expansion of connective tissue MC (CTMCs) in the jejunum, increased serum IL-4 levels, and systemic anaphylaxis following oral challenge, as evidenced by decreased body temperature and increased serum mMCP-1 levels. Intestinal MC expansion and anaphylaxis were IgE-dependent, as they did not occur in EC sensitized IgE-/-mice. Mice orally immunized with OVA+CT failed to increase serum IL-4 levels, expand their intestinal MCs, or develop anaphylaxis following oral challenge, despite OVA-specific IgE levels and splenocyte cytokine production, which were comparable to those of EC sensitized mice. CONCLUSIONS: EC sensitized mice, but not mice orally immunized with antigen+CT, develop expansion of intestinal CTMCs and IgEmediated anaphylaxis following single oral antigen challenge. IgE is necessary but not sufficient for food anaphylaxis, and MC expansion in the gut may be important for the development of anaphylaxis.
777
Maternal Transmission of Peanut Allergy Susceptibility Is Associated with IL-4 Promoter Demethylation in Offspring Ying Song, MD, Ching-feng Huang, ChangDa Liu, Paul Faybusovich, Jia Chen, PhD, Xiu-Min Li, MD; Mount Sinai School of Medicine, New York, NY. RATIONALE: Maternal allergy is believed to be a risk factor for development of peanut allergy (PNA) in children, but there is no experimental evidence verifying maternal transmission of PNA susceptibility, and possible mechanisms remain unclear. METHODS: Five-week-old offspring of PNA C3H/HeJ mothers (PNAM) were sensitized with 5mg peanut (PN) and 20mg cholera toxin for 4 weeks and challenged intragastrically with PN. Sensitized offspring of normal mothers served as control. Anaphylactic reactions, serum PNspecific IgE, and splenocyte (SPC) and mesenteric lymph node (MLN) cell production of IFN-g, IL-4, IL-5, IL-10, and IL-17 were determined. In addition, CpG methylation of the IL-4 promoter in offspring’s MLN cells was determined by pyrosequencing. RESULTS: Offspring of PNA-M exhibited significant higher PN-IgE levels at week 4, higher symptom score and lower core body temperature post challenge compared to offspring of normal mothers. SPC and MLN cells from offspring of PNA-M produced significantly more Th2 cytokines and less Th1 cytokines than cells from offspring of normal mothers. Reduced methylation at IL-4 promoter at CpG-393 and CpG-408 in MLN cells was also found in offspring of PNA-M. CONCLUSIONS: The predisposition of PNA-M offspring to produce high levels of Th2 cytokines along with a hyper PN-IgE response to active PN sensitization and strong anaphylactic reactions is associated with hypo DNA methylation at IL-4 gene promoter.
778
TUESDAY
Oral Sensitization to Peanut in Balb/c Mice Is Enhanced by Dietary Elimination of Soybean Components - towards a Better Mouse Model for Food Allergy Lisa Chang, BS1, Hugh A. Sampson, MD, FAAAAI2, Madhan Masilamani, PhD2; 1Mt. Sinai School of Medicine, New York, NY, 2Mount Sinai School of Medicine, New York, NY. RATIONALE: Food allergy research is hampered by a lack of proper animal models mimicing human food allergic responses. Laboratory mice are generally fed grain-based chow made with large amounts of soybeans. Soybeans are rich in immunomodulatory isoflavones. We tested the role of dietary soy-components in allergic sensitization to peanut in Balb/c mice. METHODS: Mice (5-10 per group) were fed regular chow or a soy-free diet for two generations. After weaning, mice were either maintained on the same diet or fed a diet containing genistein+daidzein, soy isoflavones, followed by weekly oral-sensitization with crude peanut extract (CPE) plus cholera toxin. Anaphylactic reactions to peanut were scored after peanut oral challenge at week-6 and intra-peritoneal challenge at week-7. Serum peanut-specific antibody levels were measured at week-6. RESULTS: Mice bred on a soy-free diet and sensitized and challenged with peanut showed significantly greater anaphylactic scores and peanutspecific antibodies than mice fed regular chow [mean score: 1.2 vs 0.33, _0.001; IgG15 28 vs 21; _0.01; mean Ab levels (mg/ml): IgE5 8 vs 0.5, p< p< _0.01, respectively]. Introduction of dietary isoflaIgG25 3.6 vs 1.5, p< vones to mice on a soy-free diet significantly suppressed anaphylactic scores and peanut-specific antibody levels compared to soy-free diet alone _0.01; mean Ab levels (mg/ml): IgE5 2.8 vs 8, [mean score: 0.35 vs 1.2, p< _0.05 and IgG25 0.7 vs 3.6, p< _0.001, _0.01, IgG15 15 vs 28, p< p< respectively]. CONCLUSIONS: Dietary elimination of soy components enhances peanut sensitization in Balb/c mice. This dietary manipulation may be a valuable tool to mimic human food allergy in murine models.
J ALLERGY CLIN IMMUNOL FEBRUARY 2013
779
Epicutaneous Sensitization Results in IgE-Dependent Intestinal Mast Cell Expansion and Food Anaphylaxis Raif Geha, MD1, Lisa Bartnikas, MD1, Michael Gurish2, Oliver Burton1, Sabine Leisten1, Erin Janssen1, Hans C. Oettgen, MD, PhD, FAAAAI1, Jacqueline Beaupre1, Christopher Lewis1, K. Frank Austen3, Stephanie Schulte2, Jason L. Hornick, MD, PhD2, Michiko K. Oyoshi, PhD1; 1 Boston Children’s Hospital, Boston, MA, 2Brigham and Women’s Hospital, MA, 3Brigham and Women’s Hospital/Harvard Medical School, Boston, MA. RATIONALE: Sensitization to food antigen may occur through cutaneous exposure. We tested whether epicutaneous (EC) sensitization with food antigen predisposes to IgE-mediated anaphylaxis upon oral allergen challenge. METHODS: BALB/c mice were EC sensitized by repeated application of ovalbumin (OVA) to tape-stripped skin over 7 weeks, or orally immunized with OVA and cholera toxin (CT) weekly for 8 weeks, then orally challenged with OVA. Body temperature and serum mouse mast cell protease 1 (mMCP-1) level was measured following challenge. Tissue mast cells (MCs) were examined by chloroacetate esterase staining. Serum OVA-specific IgE and IgG1 antibodies and splenocyte cytokine production were measured by ELISA. Serum interleukin-4 (IL-4) levels were measured using an in vivocytokine capture assay. RESULTS: EC sensitized mice exhibited expansion of connective tissue MC (CTMCs) in the jejunum, increased serum IL-4 levels, and systemic anaphylaxis following oral challenge, as evidenced by decreased body temperature and increased serum mMCP-1 levels. Intestinal MC expansion and anaphylaxis were IgE-dependent, as they did not occur in EC sensitized IgE-/-mice. Mice orally immunized with OVA+CT failed to increase serum IL-4 levels, expand their intestinal MCs, or develop anaphylaxis following oral challenge, despite OVA-specific IgE levels and splenocyte cytokine production, which were comparable to those of EC sensitized mice. CONCLUSIONS: EC sensitized mice, but not mice orally immunized with antigen+CT, develop expansion of intestinal CTMCs and IgEmediated anaphylaxis following single oral antigen challenge. IgE is necessary but not sufficient for food anaphylaxis, and MC expansion in the gut may be important for the development of anaphylaxis.