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Characterization of binding of human lactoferrin to pneumococcal surface protein A

Håkansson, Anders P LU ; Roche, H; Mirza, S; McDaniel, L S; Brooks-Walter, A and Briles, D E (2001) In Infection and Immunity 69(5). p.81-3372
Abstract

Human lactoferrin is an iron-binding glycoprotein that is particularly prominent in exocrine secretions and leukocytes and is also found in serum, especially during inflammation. It is able to sequester iron from microbes and has immunomodulatory functions, including inhibition of both complement activation and cytokine production. This study used mutants lacking pneumococcal surface protein A (PspA) and PspC to demonstrate that the binding of human lactoferrin to the surface of Streptococcus pneumoniae was entirely dependent on PspA. Lactoferrin bound both family 1 and family 2 PspAs. Binding of lactoferrin to PspA was shown by surface colocalization with PspA and was verified by the lack of binding to PspA-negative mutants.... (More)

Human lactoferrin is an iron-binding glycoprotein that is particularly prominent in exocrine secretions and leukocytes and is also found in serum, especially during inflammation. It is able to sequester iron from microbes and has immunomodulatory functions, including inhibition of both complement activation and cytokine production. This study used mutants lacking pneumococcal surface protein A (PspA) and PspC to demonstrate that the binding of human lactoferrin to the surface of Streptococcus pneumoniae was entirely dependent on PspA. Lactoferrin bound both family 1 and family 2 PspAs. Binding of lactoferrin to PspA was shown by surface colocalization with PspA and was verified by the lack of binding to PspA-negative mutants. Lactoferrin was expressed on the body of the cells but was largely absent from the poles. PspC showed exactly the same distribution on the pneumococcal surface as PspA but did not bind lactoferrin. PspA's binding site for lactoferrin was mapped using recombinant fragments of PspA of families 1 and 2. Binding of human lactoferrin was detected primarily in the C-terminal half of the alpha-helical domain of PspA (amino acids 167 to 288 of PspA/Rx1), with no binding to the N-terminal 115 amino acids in either strain. The interaction was highly specific. As observed previously, bovine lactoferrin bound poorly to PspA. Human transferrin did not bind PspA at all. The binding of lactoferrin to S. pneumoniae might provide a way for the bacteria to interfere with host immune functions or to aid in the acquisition of iron at the site of infection.

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author
organization
publishing date
type
Contribution to journal
publication status
published
keywords
Animals, Bacterial Proteins, Binding Sites, Cattle, Complement Activation, Humans, Lactoferrin, Species Specificity, Streptococcus pneumoniae
in
Infection and Immunity
volume
69
issue
5
pages
10 pages
publisher
American Society for Microbiology
external identifiers
  • Scopus:0035061043
ISSN
0019-9567
DOI
10.1128/IAI.69.5.3372-3381.2001
language
English
LU publication?
yes
id
f9b5fd7e-d7bf-462e-9f54-2554752bb2a7
date added to LUP
2016-05-21 11:54:53
date last changed
2016-10-26 12:20:38
@misc{f9b5fd7e-d7bf-462e-9f54-2554752bb2a7,
  abstract     = {<p>Human lactoferrin is an iron-binding glycoprotein that is particularly prominent in exocrine secretions and leukocytes and is also found in serum, especially during inflammation. It is able to sequester iron from microbes and has immunomodulatory functions, including inhibition of both complement activation and cytokine production. This study used mutants lacking pneumococcal surface protein A (PspA) and PspC to demonstrate that the binding of human lactoferrin to the surface of Streptococcus pneumoniae was entirely dependent on PspA. Lactoferrin bound both family 1 and family 2 PspAs. Binding of lactoferrin to PspA was shown by surface colocalization with PspA and was verified by the lack of binding to PspA-negative mutants. Lactoferrin was expressed on the body of the cells but was largely absent from the poles. PspC showed exactly the same distribution on the pneumococcal surface as PspA but did not bind lactoferrin. PspA's binding site for lactoferrin was mapped using recombinant fragments of PspA of families 1 and 2. Binding of human lactoferrin was detected primarily in the C-terminal half of the alpha-helical domain of PspA (amino acids 167 to 288 of PspA/Rx1), with no binding to the N-terminal 115 amino acids in either strain. The interaction was highly specific. As observed previously, bovine lactoferrin bound poorly to PspA. Human transferrin did not bind PspA at all. The binding of lactoferrin to S. pneumoniae might provide a way for the bacteria to interfere with host immune functions or to aid in the acquisition of iron at the site of infection.</p>},
  author       = {Håkansson, Anders P and Roche, H and Mirza, S and McDaniel, L S and Brooks-Walter, A and Briles, D E},
  issn         = {0019-9567},
  keyword      = {Animals,Bacterial Proteins,Binding Sites,Cattle,Complement Activation,Humans,Lactoferrin,Species Specificity,Streptococcus pneumoniae},
  language     = {eng},
  number       = {5},
  pages        = {81--3372},
  publisher    = {ARRAY(0x9a654c0)},
  series       = {Infection and Immunity},
  title        = {Characterization of binding of human lactoferrin to pneumococcal surface protein A},
  url          = {http://dx.doi.org/10.1128/IAI.69.5.3372-3381.2001},
  volume       = {69},
  year         = {2001},
}