Toward a live microbial microbicide for HIV: Commensal bacteria secreting an HIV fusion inhibitor peptide
- Srinivas Rao*,
- Stella Hu†,
- Louise McHugh†,
- Kira Lueders†,
- Ken Henry†,
- Qi Zhao*,
- Richard A. Fekete†,
- Sudeshna Kar‡,
- Sankar Adhya‡, and
- Dean H. Hamer†,§
- *Vaccine Research Center, National Institute of Allergy and Infectious Diseases, Laboratories of †Biochemistry and ‡Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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Contributed by Sankar Adhya, June 14, 2005
Abstract
Most HIV transmission occurs on the mucosal surfaces of the gastrointestinal and cervicovaginal tracts, both of which are normally coated by a biofilm of nonpathogenic commensal bacteria. We propose to genetically engineer such naturally occurring bacteria to protect against HIV infection by secreting antiviral peptides. Here we describe the development and characterization of Nissle 1917, a highly colonizing probiotic strain of Escherichia coli, secreting HIV-gp41-hemolysin A hybrid peptides that block HIV fusion and entry into target cells. By using an appropriate combination of cis- and transacting secretory and regulatory signals, micromolar secretion levels of the anti-HIV peptides were achieved. The genetically engineered Nissle 1917 were capable of colonizing mice for periods of weeks to months, predominantly in the colon and cecum, with lower concentrations of bacteria present in the rectum, vagina, and small intestine. Histological and immunocytochemical examination of the colon revealed bacterial growth and peptide secretion throughout the luminal mucosa and in association with epithelial surfaces. The use of genetically engineered live microbes as anti-HIV microbicides has important potential advantages in economy, efficacy, and durability.
Footnotes
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↵ § To whom correspondence should be addressed at: National Institutes of Health, 9000 Rockville Pike, Building 37, Room 6002, Bethesda, MD 20892. E-mail: deanh{at}helix.nih.gov.
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Author contributions: S.R., S.A., and D.H.H. designed research; S.R., S.H., L.M., K.L., K.H., Q.Z., R.A.F., S.K., and D.H.H. performed research; S.R., S.H., L.M., K.L., K.H., R.A.F., S.K., S.A., and D.H.H. analyzed data; and S.R., S.A., and D.H.H. wrote the paper.
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Abbreviations: Hly, hemolysin; Apr, ampicillin resistance; Cmr, chloramphenicol resistance; cfu, colony-forming units; Etag, epitope tag; MuLV, murine leukemia virus; IPTG, isopropyl β-d-thiogalactoside.
