Affiliation:
1. Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9048
Abstract
ABSTRACT
Haemophilus ducreyi
35000HP contains two genes,
lspA1
and
lspA2
, whose predicted protein products have molecular weights of 456,000 and 543,000, respectively (C. K. Ward, S. R. Lumbley, J. L. Latimer, L. D. Cope, and E. J. Hansen, J. Bacteriol. 180:6013-6022, 1998). We have constructed three
H. ducreyi
35000HP mutants containing antibiotic resistance cartridges in one or both of the
lspA1
and
lspA2
open reading frames. Western blot analysis using LspA1- and LspA2-specific monoclonal antibodies indicated that the wild-type parent strain 35000HP expressed LspA1 protein that was readily detectable in culture supernatant fluid together with a barely detectable amount of LspA2 protein. The
lspA2
mutant 35000HP.2 expressed LspA1 protein that was detectable in culture supernatant fluid and no LspA2 protein. In contrast, the
H. ducreyi lspA1
mutant 35000HP.1, which did not express the LspA1 protein, expressed a greater quantity of the LspA2 protein than did the wild-type parent strain. The
lspA1 lspA2
double mutant 35000HP.12 expressed neither LspA1 nor LspA2. The three mutant strains adhered to human foreskin fibroblasts and to a human keratinocyte cell line in vitro at a level that was not significantly different from that of the wild-type strain 35000HP. Lack of expression of the LspA1 protein by both the
lspA1
mutant and the
lspA1 lspA2
double mutant was associated with an increased tendency to autoagglutinate. When evaluated in the temperature-dependent rabbit model for chancroid, the
lspA1 lspA2
double mutant was substantially less virulent than the wild-type strain 35000HP. The results of these studies indicated that
H. ducreyi
requires both the LspA1 and LspA2 proteins to be fully virulent in this animal model for experimental chancroid.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
21 articles.
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