During the next funding period the research agenda will include a diverse set of investigations that are organized under a single primary goal - to improve the safety and stability of live attenuated cholera vaccines. Investigations will focus on the pathobiology of V. cholerae, the regulation of toxins and virulence factors discovered through genomic sequence analysis, and the mechanisms of horizontal transfer of virulence factor genes between strains of V. cholerae. Specifically, the investigators hope to define genes that are involved in the invasion (penetration) of mammalian HEp-2 cells by V cholerae, since this phenotype may correlate with the adverse symptoms (reactogenicity) caused by certain live cholera vaccines in human volunteer subjects. The specific mutations causing the motility defects in nonreactogenic, low invasive vaccine strains Peru-15 and Bengal-15 will also be defined by genetic methods and other defined mutations causing loss of bacterial motility will be characterized. Microarrays will be explored as a means of determining gene expression patterns across the entire V. cholerae genome for various types of regulatory mutants. The investigators will also continue analysis of the ToxR regulatory system focusing on interactions between ToxRS and TcpPH membrane proteins and the sodium pump encoded by the Nqr complex. Biochemical analysis will be performed on potential new toxins and virulence factors that have been revealed by genomic sequence analysis, microarray expression studies, and other genetic techniques. The mechanism of transfer of several genomic segments will be explored including a new phage corresponding to the TLC element, and the TCP and integron pathogenicity islands. The knowledge the investigators gain from these studies will be applied to the rationale construction and evaluation of new live, attenuated, V. cholerae vaccine candidates. The investigators will also work on the practical problem of how to prevent these vaccines strains from reacquiring the CTX phage or other genetic elements encoding virulence determinants. In an effort to accelerate functional genomics for V. cholerae, the investigators will also attempt to extend GAMBIT, a new method of genetic mapping, to V. cholerae.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI018045-23
Application #
6631647
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Program Officer
Hall, Robert H
Project Start
1981-07-01
Project End
2004-03-31
Budget Start
2003-04-01
Budget End
2004-03-31
Support Year
23
Fiscal Year
2003
Total Cost
$508,532
Indirect Cost
Name
Harvard University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
047006379
City
Boston
State
MA
Country
United States
Zip Code
02115
Del Tordello, Elena; Danilchanka, Olga; McCluskey, Andrew J et al. (2016) Type VI secretion system sheaths as nanoparticles for antigen display. Proc Natl Acad Sci U S A 113:3042-7
Fu, Yang; Mekalanos, John J (2014) Infant Rabbit Colonization Competition Assays. Bio Protoc 4:
Ho, Brian T; Dong, Tao G; Mekalanos, John J (2014) A view to a kill: the bacterial type VI secretion system. Cell Host Microbe 15:9-21
Vercruysse, Maarten; Köhrer, Caroline; Davies, Bryan W et al. (2014) The highly conserved bacterial RNase YbeY is essential in Vibrio cholerae, playing a critical role in virulence, stress regulation, and RNA processing. PLoS Pathog 10:e1004175
Basler, Marek; Ho, Brian T; Mekalanos, John J (2013) Tit-for-tat: type VI secretion system counterattack during bacterial cell-cell interactions. Cell 152:884-94
Ho, Brian T; Basler, Marek; Mekalanos, John J (2013) Type 6 secretion system-mediated immunity to type 4 secretion system-mediated gene transfer. Science 342:250-3
Fu, Yang; Waldor, Matthew K; Mekalanos, John J (2013) Tn-Seq analysis of Vibrio cholerae intestinal colonization reveals a role for T6SS-mediated antibacterial activity in the host. Cell Host Microbe 14:652-63
Danilchanka, Olga; Mekalanos, John J (2013) Cyclic dinucleotides and the innate immune response. Cell 154:962-970
Basler, M; Mekalanos, J J (2012) Type 6 secretion dynamics within and between bacterial cells. Science 337:815
Bogard, Ryan W; Davies, Bryan W; Mekalanos, John J (2012) MetR-regulated Vibrio cholerae metabolism is required for virulence. MBio 3:

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