Characterization of a Lactococcus lactis strain that secretes a major epitope of bovine beta-lactoglobulin and evaluation of its immunogenicity in mice.
Bovine beta-lactoglobulin (Blg) is one of the major cow's milk allergens. Peptide 41-60 of Blg (Blg41-60) was described as a murine T-cell determinant and a murine, rat, and human immunoglobulin E (IgE) epitope. The aim of this study was the expression of Blg41-60 as a fusion protein in the food-grade bacterium Lactococcus lactis and the characterization of its immunogenicity in mice. We constructed a recombinant strain of L. lactis capable of inducible production and secretion of Blg41-60::Nuc, a fusion protein between Blg41-60 and the mature part of the staphylococcal nuclease (Nuc). The highest production yield of Blg41-60::Nuc (32.5 mg/liter) was reached 4 h after induction. At this time, up to 75% of Blg41-60::Nuc was secreted. When monoclonal antibodies specific for Blg41-60 were used, purified Blg41-60::Nuc and synthetic Blg41-60 exhibited very similar immunoreactivities. Subcutaneous coadministration of purified Blg41-60::Nuc and killed nonrecombinant L. lactis resulted in the induction of specific anti-Blg41-60 IgG2a and IgG1. The IgG1/IgG2a ratio and the lack of specific IgE suggest a Th1-type immune response, i.e., a nonallergic response. Similar administrations of the killed Blg41-60::Nuc-producing L. lactis strain did not elicit a specific immune response, whereas a transitory mucosal IgA-specific immune response was induced in mice after oral administration of the live Blg41-60::Nuc-producing L. lactis strain.
Chatel
Jean-Marc
JM
Unité d'Immuno-Allergie Alimentaire, INRA/CEA, CE de Saclay, DRM-SPI, 91191 Gif-sur-Yvette, France.
Nouaille
Sebastien
S
Adel-Patient
Karine
K
Le Loir
Yves
Y
Boe
Herman
H
Gruss
Alexandra
A
Wal
Jean-Michel
JM
Langella
Philippe
P
D000284:Administration, Oral; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology; D002417:Cattle; D000939:Epitopes / Q000276:immunology / Q000378:metabolism*; D018928:Immunity, Mucosal; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis; D007279:Injections, Subcutaneous; D013294:Lactococcus lactis / Q000235:genetics / Q000276:immunology*; D007782:Lactoglobulins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D008836:Micrococcal Nuclease / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007071:Immunoglobulin A, Secretory; D007782:Lactoglobulins; D011993:Recombinant Fusion Proteins; D008836:Micrococcal Nuclease