Anti-idiotypic antibody fragment effective against candidiasis.

2004 JAN 7 - (NewsRx.com & NewsRx.net) -- An engineered synthetic killer anti-idiotypic antibody fragment was effective against experimental mucosal and systemic candidiasis.

"Peptides derived from the sequence of a single-chain, recombinant, anti-idiotypic antibody (IdAb; KT-scFv) acting as a functional internal image of a microbicidal, wide-spectrum yeast killer toxin (KT) were synthesized and studied for their antimicrobial activity by using the KT-susceptible Candida albicans as model organism. A decapeptide containing the first three amino acids (SAS) of the light chain CDR1 was selected and optimized by alanine replacement of a single residue," researchers in Italy report.

"This peptide exerted a strong candidacidal activity in vitro, with a 50% inhibitory concentration of 0056 micromolar, and was therefore designated killer peptide (KP)," said Luciano Polonelli and collaborators at the Istituto Superiore di Sanita, Universita degli Studi di Parma, and Universita degli Studi di Siena. "Its activity was neutralized by laminarin, a beta1-3 glucan molecule, but not by pustulan, a beta1-6 glucan molecule. KP also competed with the binding of a KT-like monoclonal IdAb to germinating cells of the fungus. In a rat model of vaginal candidiasis, local, postchallenge administration of KP was efficacious in rapidly abating infections caused by fluconazole-susceptible or -resistant C. albicans strains."

"In ...