Immunostimulatory activity of LT-IIa, a type II heat-labile enterotoxin of Escherichia coli.
Immunol Lett
; 62(2): 117-20, 1998 Jun.
Article
in En
| MEDLINE
| ID: mdl-9698108
ABSTRACT
Certain bacterial molecules potentiate immune responses to parenterally administered antigens. One such molecule that has been intensely investigated is cholera toxin, a type I heat-labile enterotoxin produced by the Gram-negative bacterium Vibrio cholerae. Immunization with a mixture of a foreign antigen and cholera toxin enhances the immune response to the antigen. Similar adjuvant activity is associated with LT-I, a closely related type I heat-labile enterotoxin produced by Escherichia coli. The adjuvant activities of LT-IIa, a member of the type II heat-labile enterotoxins produced by E. coli, have not been described. LT-IIa and CT differ significantly in amino acid sequence of the B polypeptides and in receptor binding affinity. In this study, rats were subcutaneously immunized with fimbrillin, a protein isolated from the bacterium Porphyromonas gingivalis, and with fimbrillin in combination with LT-IIa, the prototypical type II enterotoxin. Previous studies documented that fimbrillin administered alone is a poor immunogen. Animals immunized with the mixture of fimbrillin and LT-IIa produced high titers of specific IgG antibody directed against fimbrillin. Anti-fimbrillin antibody titers in sera from animals receiving the combination of LT-IIa + fimbrillin were comparable to those obtained from sera of animals immunized with cholera toxin + fimbrillin. The results of these experiments demonstrate that LT-IIa exhibits an adjuvant activity that is equal to that of cholera toxin. Recombinant methods have been established for producing large amounts of LT-IIa, an advantage that will likely provide an economic impetus to consider incorporating the enterotoxin as an immunostimulatory agent in future vaccines.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Toxins
/
Adjuvants, Immunologic
/
Escherichia coli Proteins
/
Fimbriae Proteins
/
Enterotoxins
/
Escherichia coli
Limits:
Animals
Language:
En
Journal:
Immunol Lett
Year:
1998
Document type:
Article
Affiliation country:
United States