Previous Article | Next Article 
Infection and Immunity, November 2000, p. 6094-6100, Vol. 68, No. 11
Department of Microbiology, College of
Physicians and Surgeons, Columbia University, New York, New York
10032,1 and Department of Oral Pathology
and Biology, University of Medicine and Dentistry of New Jersey,
Newark, New Jersey 071032
Received 1 June 2000/Returned for modification 12 July
2000/Accepted 2 August 2000
Actinobacillus actinomycetemcomitans, the etiologic
agent for localized juvenile periodontitis and certain other human
infections, such as endocarditis, expresses a leukotoxin that acts on
polymorphonuclear leukocytes and macrophages. Leukotoxin is a member of
the highly conserved repeat toxin (RTX) family of bacterial toxins
expressed by a variety of pathogenic bacteria. While the RTX toxins of
other bacterial species are secreted, the leukotoxin of A. actinomycetemcomitans is thought to remain associated with the
bacterial cell. We have examined leukotoxin production and localization
in rough (adherent) and smooth (nonadherent) strains of A. actinomycetemcomitans. We found that leukotoxin expressed by the
rough, adherent, clinical isolate CU1000N is indeed cell
associated, as expected. However, we were surprised to find that
smooth, nonadherent strains of A. actinomycetemcomitans, including Y4, JP2 (a strain expressing a
high level of toxin), and CU1060N (an isogenic smooth variant of
CU1000N), secrete an abundance of leukotoxin into the culture supernatants during early stages of growth. After longer times of
incubation, leukotoxin disappears from the supernatants, and its loss
is accompanied by the appearance of a number of low-molecular-weight polypeptides. The secreted leukotoxin is active, as evidenced by its ability to kill HL-60 cells in vitro. We found that the growth
phase and initial pH of the growth medium significantly affect the
abundance of secreted leukotoxin, and we have developed a rapid
(<2 h) method to partially purify large amounts of leukotoxin. Remarkably, mutations in the tad genes, which are required
for tight nonspecific adherence of A. actinomycetemcomitans
to surfaces, cause leukotoxin to be released from the bacterial cell.
These studies show that A. actinomycetemcomitans has the
potential to secrete abundant leukotoxin. It is therefore appropriate
to consider a possible role for leukotoxin secretion in the
pathogenesis of A. actinomycetemcomitans.
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Secretion of RTX Leukotoxin by Actinobacillus
actinomycetemcomitans
*
Corresponding author. Mailing address: Department of
Microbiology, College of Physicians and Surgeons, Columbia University, 701 W. 168th St., New York, NY 10032. Phone: (212) 305-3425. Fax: (212)
305-1468. E-mail: figurski{at}cuccfa.ccc.columbia.edu.
Infection and Immunity, November 2000, p. 6094-6100, Vol. 68, No. 11
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Gallant, C. V., Sedic, M., Chicoine, E. A., Ruiz, T., Mintz, K. P.
(2008). Membrane Morphology and Leukotoxin Secretion Are Associated with a Novel Membrane Protein of Aggregatibacter actinomycetemcomitans. J. Bacteriol.
190: 5972-5980
[Abstract] [Full Text] -
Isaza, M. P., Duncan, M. S., Kaplan, J. B., Kachlany, S. C.
(2008). Screen for Leukotoxin Mutants in Aggregatibacter actinomycetemcomitans: Genes of the Phosphotransferase System Are Required for Leukotoxin Biosynthesis. Infect. Immun.
76: 3561-3568
[Abstract] [Full Text] -
Chen, Q., Sun, B., Wu, H., Peng, Z., Fives-Taylor, P. M.
(2007). Differential Roles of Individual Domains in Selection of Secretion Route of a Streptococcus parasanguinis Serine-Rich Adhesin, Fap1. J. Bacteriol.
189: 7610-7617
[Abstract] [Full Text] -
Balashova, N. V., Park, D. H., Patel, J. K., Figurski, D. H., Kachlany, S. C.
(2007). Interaction between Leukotoxin and Cu,Zn Superoxide Dismutase in Aggregatibacter actinomycetemcomitans. Infect. Immun.
75: 4490-4497
[Abstract] [Full Text] -
Wu, H., Bu, S., Newell, P., Chen, Q., Fives-Taylor, P.
(2007). Two Gene Determinants Are Differentially Involved in the Biogenesis of Fap1 Precursors in Streptococcus parasanguis. J. Bacteriol.
189: 1390-1398
[Abstract] [Full Text] -
Balashova, N. V., Diaz, R., Balashov, S. V., Crosby, J. A., Kachlany, S. C.
(2006). Regulation of Aggregatibacter (Actinobacillus) actinomycetemcomitans Leukotoxin Secretion by Iron. J. Bacteriol.
188: 8658-8661
[Abstract] [Full Text] -
Balashova, N. V., Crosby, J. A., Al Ghofaily, L., Kachlany, S. C.
(2006). Leukotoxin Confers Beta-Hemolytic Activity to Actinobacillus actinomycetemcomitans. Infect. Immun.
74: 2015-2021
[Abstract] [Full Text] -
Kelk, P., Johansson, A., Claesson, R., Hanstrom, L., Kalfas, S.
(2003). Caspase 1 Involvement in Human Monocyte Lysis Induced by Actinobacillus actinomycetemcomitans Leukotoxin. Infect. Immun.
71: 4448-4455
[Abstract] [Full Text] -
Caiazza, N. C., O'Toole, G. A.
(2003). Alpha-Toxin Is Required for Biofilm Formation by Staphylococcus aureus. J. Bacteriol.
185: 3214-3217
[Abstract] [Full Text] -
HENDERSON, B., WILSON, M., SHARP, L., WARD, J. M.
(2002). Actinobacillus actinomycetemcomitans. J Med Microbiol
51: 1013-1020
[Full Text] -
Bhattacharjee, M. K., Kachlany, S. C., Fine, D. H., Figurski, D. H.
(2001). Nonspecific Adherence and Fibril Biogenesis by Actinobacillus actinomycetemcomitans: TadA Protein Is an ATPase. J. Bacteriol.
183: 5927-5936
[Abstract] [Full Text]
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»