A cationic antimicrobial peptide enhances the infectivity of Coxiella burnetii.
Purified Coxiella burnetii (Nine Mile, phase I) ricketssiae were exposed to a synthetic peptide (CAP37(20-44)) based on the amino acid sequence of CAP37--a 37 K human neutrophil granule-associated cationic antimicrobial protein--and their capacity to infect L929 mouse fibroblast cells was assessed during a 10-day post-exposure period. Because the parasite thrives within the acidic phagolysosome we anticipated that CAP37(20-44) would have no adverse effect on the organism. This was borne out by the experiments; however, to our surprise, treated C. burnetii had a much greater capacity to infect L cells than the non-treated counterpart. We speculate that the peptide exhibits opsonin-like properties, enhancing attachment of the rickettsia to the host cell surface and subsequent entry.
Aragon
A S
AS
Biology Department, University of New Mexico, Albuquerque 8713-1091, USA.
Pereira
H A
HA
Baca
O G
OG
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins / Q000494:pharmacology*; D002352:Carrier Proteins; D002460:Cell Line; D016997:Coxiella burnetii / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051379:Mice
C062991:AZU1 protein, human; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins