Construction and evaluation of a O139 Vibrio cholerae vaccine candidate based on a hemA gene mutation.
In this paper, we describe the development of VCUSM2, a live metabolic auxotroph of Vibrio cholerae O139. Auxotrophy was achieved by mutating a house keeping gene, hemA, that encodes for glutamyl-tRNA reductase, an important enzyme in the C5 pathway for delta-aminolevulenic acid (ALA) biosynthesis, which renders this strain dependent on exogenous ALA for survival. Experiments using the infant mouse and adult rabbit models show that VCUSM2 is a good colonizer of the small intestine and elicits greater than a four-fold rise in vibriocidal antibodies in vaccinated rabbits. Rabbits vaccinated with VCUSM2 were fully protected against subsequent challenge with 1 x 10(11) CFU of the virulent wild type (WT) strain. Experiments using ligated ileal loops of rabbits show that VCUSM2 is 2.5-fold less toxic at the dose of 1 x 10(6) CFU compared to the WT strain. Shedding of VCUSM2 in rabbits were found to occur for no longer than 4 days and its maximum survival rate in environmental waters is 8 days compared to the greater than 20 days for the WT strain. VCUSM2 is thus a potential vaccine candidate against infection by V. cholerae O139.
Ravichandran
Manickam
M
Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia Health Campus, Kubang Kerian 16150, Kelantan, Malaysia. mravic@kb.usm.my
Ali
Syed Atif
SA
Rashid
Nur Haslindawaty Abdul
NH
Kurunathan
Sinniah
S
Yean
Chan Yean
CY
Ting
Lai Chin
LC
Bakar
Afifi Sheikh Abu
AS
Lalitha
Pattabiraman
P
Zainuddin
Zainul F
ZF
D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002771:Cholera / Q000517:prevention & control*; D002772:Cholera Toxin / Q000276:immunology; D022121:Cholera Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007421:Intestine, Small / Q000382:microbiology; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D011817:Rabbits; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D041242:Vibrio cholerae O139 / Q000235:genetics / Q000254:growth & development / Q000276:immunology*; D014774:Virulence
D000907:Antibodies, Bacterial; D022121:Cholera Vaccines; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D014613:Vaccines, Attenuated; D002772:Cholera Toxin; D000445:Aldehyde Oxidoreductases; C067282:glutamyl tRNA reductase