Molecular cloning, biochemical characterization, and partial protective immunity of the heme-binding glutathione S-transferases from the human hookworm Necator americanus.
Hookworm glutathione S-transferases (GSTs) are critical for parasite blood feeding and survival and represent potential targets for vaccination. Three cDNAs, each encoding a full-length GST protein from the human hookworm Necator americanus (and designated Na-GST-1, Na-GST-2, and Na-GST-3, respectively) were isolated from cDNA based on their sequence similarity to Ac-GST-1, a GST from the dog hookworm Ancylostoma caninum. The open reading frames of the three N. americanus GSTs each contain 206 amino acids with 51% to 69% sequence identity between each other and Ac-GST-1. Sequence alignment with GSTs from other organisms shows that the three Na-GSTs belong to a nematode-specific nu-class GST family. All three Na-GSTs, when expressed in Pichia pastoris, exhibited low lipid peroxidase and glutathione-conjugating enzymatic activities but high heme-binding capacities, and they may be involved in the detoxification and/or transport of heme. In two separate vaccine trials, recombinant Na-GST-1 formulated with Alhydrogel elicited 32 and 39% reductions in adult hookworm burdens (P < 0.05) following N. americanus larval challenge relative to the results for a group immunized with Alhydrogel alone. In contrast, no protection was observed in vaccine trials with Na-GST-2 or Na-GST-3. On the basis of these and other preclinical data, Na-GST-1 is under possible consideration for further vaccine development.
Zhan
Bin
B
Department of Microbiology and Tropical Medicine, The George Washington University and Sabin Vaccine Institute, Ross Hall 736, 2300 Eye St NW, Washington, DC 20037, USA. mtmbxz@gwumc.edu
Perally
Samirah
S
Brophy
Peter M
PM
Xue
Jian
J
Goud
Gaddam
G
Liu
Sen
S
Deumic
Vehid
V
de Oliveira
Luciana M
LM
Bethony
Jeffrey
J
Bottazzi
Maria Elena
ME
Jiang
Desheng
D
Gillespie
Portia
P
Xiao
Shu-Hua
SH
Gupta
Richi
R
Loukas
Alex
A
Ranjit
Najju
N
Lustigman
Sara
S
Oksov
Yelena
Y
Hotez
Peter
P
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000536:Aluminum Hydroxide / Q000008:administration & dosage; D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D018509:DNA, Helminth / Q000235:genetics / Q000302:isolation & purification; D015870:Gene Expression; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D006418:Heme / Q000378:metabolism*; D006801:Humans; D015227:Lipid Peroxidation; D008969:Molecular Sequence Data; D017221:Necator americanus / Q000201:enzymology* / Q000235:genetics / Q000276:immunology*; D009332:Necatoriasis / Q000276:immunology / Q000517:prevention & control*; D016366:Open Reading Frames; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D022223:Vaccines, Subunit / Q000276:immunology
D000276:Adjuvants, Immunologic; D000947:Antigens, Helminth; D018076:DNA, Complementary; D018509:DNA, Helminth; D011994:Recombinant Proteins; D022223:Vaccines, Subunit; D006418:Heme; D000536:Aluminum Hydroxide; D005982:Glutathione Transferase; D005978:Glutathione