A Novel Single Domain Antibody Targeting FliC Flagellin of Salmonella enterica for Effective Inhibition of Host Cell Invasion

Abstract

The enteric pathogen, Salmonella enterica is a major cause of human gastroenteritis globally and with increasing bacterial resistance to antibiotics, alternative solutions are urgently needed. Single domain antibodies (sdAbs), the smallest antibody fragments that retain antigen binding specificity and affinity, are derived from variable heavy-chain only fragments (VHH) of camelid heavy-chain-only immunoglobulins. SdAbs typically contain a single disulfide bond simplifying recombinant protein production in microbial systems. These factors make sdAbs ideally suited for the development of effective anti-bacterial therapeutics. To this end, we generated an anti-Salmonella VHH library from which we screened for high affinity sdAbs. We present a novel sdAb (Abi-Se07) that targets the Salmonella virulence factor, FliC, required for bacterial motility and invasion of host cells. We demonstrate that Abi-Se07 bound FliC with a KD of 16.2 ± 0.1 nM. In addition, Abi-Se07 exhibited cross-serovar binding to whole cells of S. enterica serovar Typhimurium, Heidelberg, and Hadar. Abi-Se07 significantly inhibited bacterial motility and significantly reduced S. enterica colonization in a more native environment of chicken jejunum epithelium. Taken together, we have identified a novel anti-Salmonella sdAb and discuss future efforts toward therapeutic development.

Reversal of carbapenem resistance inPseudomonas aeruginosaby camelid single domain antibody fragment (VHH) against the C4 dicarboxylate transporter

“…Antibody based biologicals have a key property of specificity that sets it apart from small molecules that can be used to develop target specific therapy as well as accurate diagnostic tests. There are few reports on in-vitro cross-reactivity of VHH fragments against viruses (33,34 ) and bacteria (35). However, the specificity of the PsC23 binding to P aeruginosa and reproducibility of this technique indicates the robustness of our screening strategy, which can be used to quickly isolate antibodies against other pathogens as well.…”

Exploring of spectrum beta lactamase producing multidrug-resistant Salmonella enterica serovars in goat meat markets of Bangladesh

“… ( Dias De Oliveira et al, 2005 ) sefA F- GATACTGCTGAACGTAGAAGG R- GCGTAAATCAGCATCTGCAGTAGC 488 bp S . Enteritidis ( Doran et al, 1996 ) fliC F- CGGTGTTGCCCAGGTTGGTAAT R- ACTGGTAAAGATGGCT 620 bp S. Typhimurium ( Huen et al, 2019 ) bla TEM F- CATTTCCGTGTCGCCCTTATTC R- CGTTCATCCATAGTTGCCTGAC 800 bp TEM 1 & 2 ( Wang et al, 2019 ) bla SHV F- AGCCGCTTGAGCAAATTAAAC R- ATCCCGCAGATAAATCACCAC 713 bp SHV-1 bla OXA F- GGCACCAGATTCAACTTTCAAG R- GACCCCAAGTTTCCTGTAAGTG 564 bp OXA-1,4 & 30 bla CTX-M1 F-TTAGGAAATGTGCCGCTGTA R-CGATATCGTTGGTGGTACCAT 688 bp CTX-M-1, CTX-M-3, & CTX-M-15 bla CTX-M2 F-CGTTAACGGCACGATGAC R-CGATATCGTTGGTGGTACCAT 404 bp CTX-M-2 bla CTX-M9 F-TCAAGCCTGCCGATCTGGT R-TGATTCTCGCCGCTGAAG 561 bp CTX-M-9 & CTX-M-14 MultiCase ACC F-CACCTCCAGCGACTTGTTAC R-GTTAGCCAGCATCACGATCC 346 bp ACC-1 & ACC-2 MultiCase MOX F-GCAACAACGACAATCCATCCT R-GGGATAGGCGTAACTCTCCCAA 895 bp MOX-1, MOX-2, CMY-1, CMY-8 to CMY-11& CMY-19 MultiCase DHA F-TGATGGCACAGCAGGATATTC R-GCTTTGACTCTTTCGGTATTCG 997 bp DHA-1 & DHA-2 …”

Nanobodies in the fight against infectious diseases: repurposing nature's tiny weapons

“…For example, to interfere with the ability of Campylobacter to colonize the host, Nbs were tested by targeting an outer membrane protein and the flagella (Vanmarsenille et al 2018 ). Other Nbs targeted the F4 fimbriae of E. coli (Harmsen et al 2005 ), the Salmonella enterica FilC flagellin (Huen et al 2019 ), and the Streptococcus mutans adhesin (Krüger et al 2006 ). Another group of Nbs were developed to target the toxins produced by some pathogens so that they block their toxic effects on the host’s cells.…”