A cloned gene of Cryptosporidium parvum encodes neutralization-sensitive epitopes

• Published in: Molecular and biochemical parasitology Vol. 80; no. 2; pp. 137 - 147
• Main Authors: Perryman, Lance E, Jasmer, Douglas P, Riggs, Michael W, Bohnet, Stewart G, McGuire, Travis C, Arrowood, Michael J
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.1996
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Antibodies, Monoclonal; antigen-antibody reactions; Antigens, Protozoan - genetics; Base Sequence; chromosome mapping; cloning; Cloning, Molecular; complementary DNA; Cryptosporidiosis - immunology; Cryptosporidiosis - prevention & control; Cryptosporidium parvum; Cryptosporidium parvum - genetics; Cryptosporidium parvum - immunology; DNA, Complementary - genetics; DNA, Protozoan - genetics; Epitope; epitope mapping; epitopes; Epitopes - genetics; genbank/u34390; Genes; Genes, Protozoan; Immunization; Infectious immunity; Mice; Mice, Inbred BALB C; Molecular Sequence Data; monoclonal antibodies; Mouse; Neutralization Tests; nucleotide sequences; Open Reading Frames; Peptides - genetics; Peptides - immunology; Recombinant Proteins - genetics; Recombinant Proteins - immunology; structural genes; ORF; RT; Epitope; Infectious immunity; Genes; kDa; bp; mAb; p; C. parvum; Cryptosporidium parvum; Mouse; kb; IPTG; HBSS; PCR
• ISSN: 0166-6851; 1872-9428
• DOI: 10.1016/0166-6851(96)02681-3

Two mAb, C6B6 and 7D10, each significantly reduced infection of mice by Cryptosporidium parvum and reacted with a 23-kDa glycoprotein (p23) of geographically disperse C. parvum isolates. The antibodies were used to identify plaques in a cDNA library prepared from C. parvum sporozoite mRNA. cDNA insert sequences from positive plaques were determined and used to isolate additional clones encoding p23 coding sequences. A consensus open reading frame of 333 base pairs, encoding 111 amino acids, was identified in this collection of cDNAs. The predicted amino acid sequence contained one N-glycosylation site, but lacked hydrophobic membrane spanning regions. Epitope mapping revealed that mAb 7D10 defines the linear epitope QDKPAD which occurs twice in the C terminal region of the peptide encoded by the ORF. This same C terminal peptide region contains a non-linear epitope bound by mAb C6B6. Serum from mice immunized with synthetic C terminal peptide reacted with sporozoite p23. The occurrence of neutralization-sensitive epitopes encoded by defined regions of the C. parvum genome suggests that recombinant proteins or synthetic peptides containing these epitopes may prove useful for inducing immune responses that diminish infection.