Neonatal mono-colonization of germ-free mice with Lactobacillus casei enhances casein immunogenicity after oral sensitization to cow's milk.
Food allergy is an increasing global health problem and perinatal administration of probiotic bacteria is currently under investigation in order to prevent the development of allergic diseases. Here, we investigated the impact of neonatal mono-colonization of mice with Lactobacillus casei BL23 on an oral sensitization to cow's milk.



Mono-colonized (LC) mice were obtained by inoculating L. casei to germ-free (GF) parents. Nine-week-old GF, LC, and conventional (CV) mice were orally sensitized to cow's milk with cholera toxin as adjuvant. Compared to GF and CV mice, LC mice developed higher casein-specific IgG responses. In contrast, no significant differences between GF and LC mice were observed for the humoral responses against whey proteins. Immunoblotting experiments performed on αS1-casein hydrolysates revealed the presence of small peptides immunoreactive with sera from LC mice but not from GF mice. After in vitro reactivation of splenocytes, secretion of IL-17 was higher in LC mice than in GF and CV mice.



Neonatal mono-colonization by L. casei BL23 modulated the allergic sensitization toward food antigens. Furthermore, our data suggest that casein-specific humoral responses in LC mice were enhanced because of casein hydrolysis by L. casei into immunogenic peptides.
UMR Service de Pharmacologie et d'Immunoanalyse, CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.
Matieny Aicha
MA
Maiga
UMR Service de Pharmacologie et d'Immunoanalyse, CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.
Stéphanie
S
Morin
UMR Service de Pharmacologie et d'Immunoanalyse, CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.
Hervé
H
Bernard
Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France.
Sylvie
S
Rabot
UMR Service de Pharmacologie et d'Immunoanalyse, CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.
Karine
K
Adel-Patient
UMR Service de Pharmacologie et d'Immunoanalyse, CEA, INRA, Université Paris-Saclay, Gif-sur-Yvette, France.
Stéphane
S
Hazebrouck
D000818:Animals; D000831:Animals, Newborn; D002364:Caseins / Q000276:immunology*; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology / Q000382:microbiology*; D005856:Germ-Free Life; D007074:Immunoglobulin G / Q000097:blood; D007780:Lacticaseibacillus casei; D051379:Mice; D008807:Mice, Inbred BALB C; D016269:Milk Hypersensitivity / Q000276:immunology*
D002364:Caseins; D007074:Immunoglobulin G
Allergy; Casein; Germ-free mice; Lactobacillus casei; Neonatal colonization