Blood-feeding insects inject potent salivary components including complement inhibitors into their host's skin to acquire a blood meal. Sand fly saliva was shown to inhibit the classical pathway of complement; however, the molecular identity of the inhibitor remains unknown. Here, we identified SALO as the classical pathway complement inhibitor. SALO, an 11 kDa protein, has no homology to proteins of any other organism apart from New World sand flies. rSALO anti-complement activity has the same chromatographic properties as the Lu. longipalpis salivary gland homogenate (SGH)counterparts and anti-rSALO antibodies blocked the classical pathway complement activity of rSALO and SGH. Both rSALO and SGH inhibited C4b deposition and cleavage of C4. rSALO, however, did not inhibit the protease activity of C1s nor the enzymatic activity of factor Xa, uPA, thrombin, kallikrein, trypsin and plasmin. Importantly, rSALO did not inhibit the alternative or the lectin pathway of complement. In conclusion our data shows that SALO is a specific classical pathway complement inhibitor present in the saliva of Lu. longipalpis. Importantly, due to its small size and specificity, SALO may offer a therapeutic alternative for complement classical pathway-mediated pathogenic effects in human diseases.

• MeSH
• aktivace komplementu účinky léků   MeSH
• hmyzí proteiny farmakologie   MeSH
• inhibitory komplementu farmakologie   MeSH
• klasická dráha komplementu účinky léků   MeSH
• komplement 4 antagonisté a inhibitory   imunologie   metabolismus   MeSH
• komplement C1 antagonisté a inhibitory   imunologie   metabolismus   MeSH
• lidé MeSH
• Psychodidae imunologie   metabolismus   MeSH
• rekombinantní proteiny farmakologie   MeSH
• sliny metabolismus   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• hmyzí proteiny MeSH
• inhibitory komplementu MeSH
• komplement 4 MeSH
• komplement C1 MeSH
• rekombinantní proteiny MeSH

DNA aptamers were developed against lipopolysaccharide (LPS) from E. coli O111:B4 and shown to bind both LPS and E. coli by a colorimetric enzyme-based microplate assay. The polyclonal aptamers were coupled to human C1qrs protein either directly using a bifunctional linker or indirectly using biotinylated aptamers and a streptavidin-C1qrs complex. Both systems significantly reduced colony counts when applied to E. coli O111:B4 and K12 strains across a series of 10x dilutions of the bacteria in the presence of human serum; it was diluted 1: 10(3) in order to avoid significant bacterial lysis by the competing alternate pathway of complement activation. A number of candidate DNA aptamer sequences were cloned and sequenced from the anti-LPS aptamer library for future screening of antibacterial or "antibiotic" potential and to aid in eventual development of an alternative therapy for antibiotic-resistant bacterial infections.

• MeSH
• antibakteriální látky chemie   imunologie   farmakologie   MeSH
• aptamerová technika SELEX MeSH
• aptamery nukleotidové chemie   genetika   imunologie   farmakologie   MeSH
• Escherichia coli účinky léků   imunologie   MeSH
• infekce vyvolané Escherichia coli farmakoterapie   imunologie   MeSH
• komplement C1 chemie   imunologie   MeSH
• lidé MeSH
• lipopolysacharidy chemie   imunologie   MeSH
• molekulární sekvence - údaje MeSH
• sekvence nukleotidů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• antibakteriální látky MeSH
• aptamery nukleotidové MeSH
• komplement C1 MeSH
• lipopolysacharidy MeSH