Delayed bacterial colonization of the gut alters the host immune response to oral sensitization against cow's milk proteins.
METHODS
Cow's milk allergy is the most prevalent food allergy in infants whose immune system development is critically stimulated during postnatal gut colonization by commensal bacteria. Allergenic potential of cow's milk β-lactoglobulin (BLG) and caseins (CAS) was investigated in germ-free (GF) BALB/c mice and in GF mice conventionalized (CVd) at 6 weeks of age.


RESULTS
Oral sensitization to cow's milk in the presence of cholera toxin led to higher BLG-specific IgE, IgG1, and IgG2a responses in GF mice than in conventional (CV) mice. No significant difference was observed for CAS-specific IgE responses although IgG1 responses to αS1- and κ-caseins were higher in GF mice than in CV mice. CVd mice, orally inoculated with fecal preparations from CV mice, also displayed biased antibody responses compared to CV mice. Secretion of Th2 cytokines by BLG- and CAS-reactivated splenocytes of CVd mice was similar to that of GF mice whereas cytokine production by reactivated cells from mesenteric lymph nodes of CVd mice was equivalent to that of CV mice.


CONCLUSIONS
Oral sensitization to BLG and CAS was differentially affected by the absence of gut microbiota and delayed bacterial colonization altered persistently the host immune response to oral sensitization against food antigens.
INRA, UR 496 - Immuno-Allergie Alimentaire, CEA/iBiTeC-S/SPI, CEA de Saclay, Gif-sur-Yvette, France.
Stéphanie
S
Morin
Romy
R
Fischer
Laetitia
L
Przybylski-Nicaise
Hervé
H
Bernard
Gérard
G
Corthier
Sylvie
S
Rabot
Jean-Michel
JM
Wal
Stéphane
S
Hazebrouck
D000818:Animals; D002364:Caseins / Q000276:immunology*; D002772:Cholera Toxin / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004247:DNA / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005856:Germ-Free Life; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007782:Lactoglobulins / Q000276:immunology*; D054892:Metagenome; D051379:Mice; D008807:Mice, Inbred BALB C; D008892:Milk / Q000276:immunology; D016269:Milk Hypersensitivity / Q000276:immunology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013154:Spleen / Q000166:cytology / Q000187:drug effects
D002364:Caseins; D016207:Cytokines; D007074:Immunoglobulin G; D007782:Lactoglobulins; D012336:RNA, Ribosomal, 16S; D007073:Immunoglobulin E; D004247:DNA; D002772:Cholera Toxin