title: Immunological response in egg-sensitive adults challenged with cheese containing or not containing lysozyme.
abstract: OBJECTIVE
  Lysozyme is an enzyme that hydrolyzes bacterial peptidoglicans. For this reason, it is used in cheese manufacturing in order to prevent a defect of long-ripened hard cheese called "late blowing" due to the outgrowth of spores of Clostridium tyrobutyricum and Clostridium butyricum. Moreover, germination of Listeria monocytogenes spores into vegetative cells is also sensitive to lysozyme. The enzyme can be an allergenic molecule, and for this reason there are concerns about its use in food industry. The immunological and clinical response of consumption of lysozyme-containing cheese has been evaluated in 25 egg-sensitive subjects with or without lysozyme sensitization.
  
  
  METHODS
  A total of 25 egg-sensitive subjects were enrolled in this study. All the subjects were already treated for egg-sensitization and presented a positive skin prick test. All the subjects had a body mass index ≤ 25 kg/m(2) and were in the age range of 20-50 years. Each subject was studied twice and received randomly 30 g of Grana Padano (containing lysozyme) or TrentinGrana cheese (lysozyme-free) of two different aging periods: 16 or 24 months. A washout period of 1 week between each cheese intake was adopted. Blood samples were taken in fasting conditions and 1 hour after cheese intake and IgA, total IgE, and lysozyme-, ovomucoid-, and ovalbumin-specific IgE were measured.
  
  
  RESULTS
  No adverse reactions were observed in both groups of patients after cheese samples were given. Lysozyme did not determine any variation of specific IgE compared with basal level. In lysozyme-sensitive patients a significant relationship between IgA and lysozyme-specific IgE was observed when lysozyme-containing cheese was given, confirming that lysozyme can pass the gut barrier.
  
  
  CONCLUSIONS
  Neither adverse events nor immunological responses were observed after ingestion of cheese containing lysozyme. However, the immunological properties of peptides deriving from cheese protein hydrolysis need to be clarified, as does the effect of lysozyme on bacterial proteolytic activity.
authors.affiliation: Institute of Food Science, Faculty of Agriculture, Catholic University, Via Emilia Parmense 84, 29122 Piacenza, Italy. filippo.rossi@unicatt.it
authors.forename: Filippo
authors.initials: F
authors.lastname: Rossi
authors.forename: Amerigo
authors.initials: A
authors.lastname: Iaconelli
authors.forename: Lucia
authors.initials: L
authors.lastname: Fiorentini
authors.forename: Francesco
authors.initials: F
authors.lastname: Zito
authors.forename: Maria Benedett
authors.initials: MB
authors.lastname: Donati
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: De Cristofaro
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Piva
authors.forename: Geltrude
authors.initials: G
authors.lastname: Mingrone
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology; D015992:Body Mass Index; D002611:Cheese / Q000032:analysis* / Q000382:microbiology*; D046972:Clostridium butyricum / Q000254:growth & development / Q000302:isolation & purification; D048014:Clostridium tyrobutyricum / Q000254:growth & development / Q000302:isolation & purification; D004311:Double-Blind Method; D021181:Egg Hypersensitivity / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007073:Immunoglobulin E / Q000097:blood; D008089:Listeria monocytogenes / Q000254:growth & development / Q000302:isolation & purification; D008875:Middle Aged; D016269:Milk Hypersensitivity / Q000276:immunology*; D009113:Muramidase / Q000009:adverse effects* / Q000097:blood / Q000276:immunology; D010059:Ovomucin / Q000097:blood / Q000276:immunology; D012882:Skin Tests; D013171:Spores, Bacterial / Q000254:growth & development / Q000276:immunology; D055815:Young Adult
chemical_list: D000485:Allergens; D007070:Immunoglobulin A; D010059:Ovomucin; D007073:Immunoglobulin E; D009113:Muramidase
keywords: allergenicity; cheese; lysozyme