Biomaterial Database

Identification of a cross-reactive continuous B-cell epitope in enterotoxigenic Escherichia coli colonization factor antigen I. 1996

A Rudin, and A M Svennerholm

Department of Medical Microbiology and Immunology, Göteborg University, Sweden. anna.rudin@microbio.gu.se.

Enterotoxigenic Escherichia coli (ETEC) colonizes the intestine by means of several antigenically distinct colonization factors (CFs). Several of these CFs have very significant amino acid sequence similarity or identity, particularly in the N-terminal end. We have previously shown that a monoclonal antibody (MAb) raised against the subunits of colonization factor antigen I (CFA/I) fimbriae, which reacts with a peptide corresponding to the 25 N-terminal amino acids of such subunits, can inhibit attachment to intestinal cells of ETEC expressing heterologous as well as homologous CFs, with related amino acid sequences. In this study we have, by means of Pepscan analysis, determined the sequence of the MAb-specific linear epitope to be 15IDLLQ19. Parenteral immunization of rabbits with an N-terminal 25-mer synthetic peptide of CFA/I fimbrial subunit, either covalently coupled to bovine serum albumin or uncoupled, induced high titers of specific antibodies against this peptide as well as against CFA/I fimbriae. Increased titers against several heterologous CF fimbriae with a related N-terminal sequence were also induced, whereas no increase was seen against fimbriae with an unrelated sequence. Neither antisera against the coupled peptide nor antisera against the uncoupled peptide inhibited binding of CF-expressing bacteria to the human intestinal cell line Caco-2 in spite of high titers. The difference in the inhibitory capabilities of the antipeptide sera and the MAb might be due to slightly different epitope specificities. Thus, whereas the antipeptide sera bound to several continuous epitopes in the N-terminal end, none of them reacted specifically with the epitope 15IDLLQ19.

UI	MeSH Term	Description	Entries
D007106	Immune Sera	Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.	Antisera,Immune Serums,Sera, Immune,Serums, Immune
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D010861	Fimbriae, Bacterial	Thin, hairlike appendages, 1 to 20 microns in length and often occurring in large numbers, present on the cells of gram-negative bacteria, particularly Enterobacteriaceae and Neisseria. Unlike flagella, they do not possess motility, but being protein (pilin) in nature, they possess antigenic and hemagglutinating properties. They are of medical importance because some fimbriae mediate the attachment of bacteria to cells via adhesins (ADHESINS, BACTERIAL). Bacterial fimbriae refer to common pili, to be distinguished from the preferred use of "pili", which is confined to sex pili (PILI, SEX).	Bacterial Fimbriae,Bacterial Pili,Common Fimbriae,Common Pili,Pili, Bacterial,Pili, Common,Bacterial Fimbria,Bacterial Pilus,Common Fimbria,Common Pilus,Fimbria, Bacterial,Pilus, Bacterial,Fimbria, Common,Fimbriae, Common,Pilus, Common
D003429	Cross Reactions	Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.	Cross Reaction,Reaction, Cross,Reactions, Cross
D004768	Enterotoxins	Substances that are toxic to the intestinal tract causing vomiting, diarrhea, etc.; most common enterotoxins are produced by bacteria.	Staphylococcal Enterotoxin,Enterotoxin,Staphylococcal Enterotoxins,Enterotoxin, Staphylococcal,Enterotoxins, Staphylococcal
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein