Скачать презентацию Cross-sensitization to milk proteins Reactivity to a kosher Скачать презентацию Cross-sensitization to milk proteins Reactivity to a kosher

602fcbaa24c6767b05647e4df280314c.ppt

  • Количество слайдов: 27

Cross-sensitization to milk proteins: Reactivity to a kosher epitope? Michael Goldberg, MD, Ph. D Cross-sensitization to milk proteins: Reactivity to a kosher epitope? Michael Goldberg, MD, Ph. D Institute of Allergy and Immunology Assaf Harofeh Medical Center

Epidemiology: Who is really allergic? • The literature reports between 2– 5% during the Epidemiology: Who is really allergic? • The literature reports between 2– 5% during the first three years of life. • The prevalence of self-diagnosed CMA in the community is 10 -fold higher than the clinically proven incidence, suggesting a sizable population is unnecessarily eschewing dairy products (J Am Coll Nutr. 2005 Dec; 24(6 Suppl): 582 S-91 S ). • True incidence in Israel is less than 0. 5% of the population (Katz, et al. JACI abstract 2009). • Near-fatal or fatal outcomes occurs primarily in the older children and adolescents.

Not Crossreacting Kosher Nonkosher Not Crossreacting Kosher Nonkosher

Hypothesis • Milk derived from kosher animals and not from nonkosher animals are reactive Hypothesis • Milk derived from kosher animals and not from nonkosher animals are reactive in Ig. E-mediated cow’s milk protein allergy (Katz, et al. Isr Med Assoc J. 10: 1 -4. )

SKIN PRICK TEST (SPT) Cow`s milk allergy or drug allergy ? ? SKIN PRICK TEST (SPT) Cow`s milk allergy or drug allergy ? ?

SPT results in cow’s milk protein allergic patients Wheal/flare (Katz, et al. Isr Med SPT results in cow’s milk protein allergic patients Wheal/flare (Katz, et al. Isr Med Assoc J. 10: 1 -4. )

SPT results in Control Group (Katz, et al. Isr Med Assoc J. 10: 1 SPT results in Control Group (Katz, et al. Isr Med Assoc J. 10: 1 -4. )

Cross reactivity of CMP with proteins from milk of other animals – response to Cross reactivity of CMP with proteins from milk of other animals – response to Non. Kosher “age dependent” Kosher – Cross * Allergenicity • • • Non Kosher – No Cross Allergenicity ** • Camel [2/8+8/47] Cow [24/24 + 47/47] • Pig [5/24 +12/47] Buffalo [24/24] • Rabbit [4/47] Goat [46/47] • Dog [16/47] Ibex [24/24+46/47] • Horse [3/42] Deer [24/24] • Alpaca [10/47] Giraffe [46/47] • * p = 0. 02 (Fisher test) • ** p > 0. 35

Cross reactivity of CMP with proteins from milk of other animals – response to Cross reactivity of CMP with proteins from milk of other animals – response to Non. Kosher “age dependent” Below 30 m/ Kosher – Cross * Allergenicity • • • Cow [24/24 + 47/47] Buffalo [24/24] Goat [46/47] Ibex [24/24+46/47] Deer [24/24] Giraffe [46/47] Non Kosher – No Cross Allergenicity ** • • • over 30 m Camel [2/8+8/47] 1/8 Pig [5/24 +12/47] 1/11 # Rabbit [4/47] 0/4 Dog [16/47] 4/12 ## Horse [3/42] 0/3 Alpaca [10/47] 1/9 • * p = 0. 02 (Fisher test) Logistic regression for moth of life • ** p > 0. 35 # OR= 1. 008, ## OR=1. 026

Is there a common epitope found only in kosher animals? Is there a common epitope found only in kosher animals?

Main characteristics of the bovine milk proteins Wal, JM. Ann Allergy Asthma Immunol. 2004 Main characteristics of the bovine milk proteins Wal, JM. Ann Allergy Asthma Immunol. 2004

Beta-lactoglobulin Beta-lactoglobulin

Beta-Casein Beta-Casein

Alpha-lactalbumin Alpha-lactalbumin

Cow Buffalo Deer Ibex Sheep Camel Horse Pig Human Cow Buffalo Deer Ibex Sheep Camel Horse Pig Human

This eight amino acid sequence creates a completely new structure C C=C This eight amino acid sequence creates a completely new structure C C=C

Schematic model of kappa-casein multimers in bovine and human milk Rasmusssen, International Dairy Journal, Schematic model of kappa-casein multimers in bovine and human milk Rasmusssen, International Dairy Journal, 1999

VPAKSCQA/D-Sequence responsible for allergenicity? Hypothesis • Aggregation of casein monomers reveals new determinants that VPAKSCQA/D-Sequence responsible for allergenicity? Hypothesis • Aggregation of casein monomers reveals new determinants that seem to be absent in the monomeric forms, since some sera show Ig. E reactivity only against aggregates, but not against individual components (Allergy. 1996; Jun; 51(6): 412 -6) • When bovine kappa-casein was expressed in the mouse a a different micellar structure was noted (J Dairy Sci 79: 791 -799, 1996) • This region may therefore lead to the generation of multiple allergenic epitopes in susceptible individuals.

Approach • Structural analysis of the native and mutated kappa casein – Modeling – Approach • Structural analysis of the native and mutated kappa casein – Modeling – Limited proteolytic digestion maintaining the disulfide bond intact • Generation of wildtype and mutated kappa-casein – In vitro-mammalian expression systems – In vivo- transgenic mouse lines • Analyze mutated kappa-casein both by SPT on milk -allergic patients and their sera for Ig. E binding antibodies

Ser 88 Ser 88

Trypsin digests reveals Arg at #97 and Lys at 111 & 112 are sensitive Trypsin digests reveals Arg at #97 and Lys at 111 & 112 are sensitive sites

Chymosin digestion of kappa-casein Chymosin digestion of kappa-casein

• Difference in micellar structure between wildtype mice and mice carrying bovine kappa-casein • Difference in micellar structure between wildtype mice and mice carrying bovine kappa-casein gene • Milk derived from transgenic mice with the bovine kappa-casein gene form a stronger curd.

Acknowledgements • Yitzhak Katz, Director, Institute of Allergy and Immunology, Assaf Harofeh Medical Center Acknowledgements • Yitzhak Katz, Director, Institute of Allergy and Immunology, Assaf Harofeh Medical Center • Richard Friedman, Columbia University, NY • Menachem Shoham, Case Western University • Alberto Huberman, University of Mexico, UNAM • James D. Murray, UC Davis • Elizabeth Maga, UC Davis Funded by: קרן המחקר של מועצת החלב