Streptococcus pneumonia surface protein SpsA CbpA binds human pIgR via domains 3 and 4

1
Streptococcus pneumonia surface protein SpsA
(CbpA) binds human pIgR via domains 3 and 4

• Finn-Eirik Johansen Ranveig Braathen Christine
  Elm and Sven Hammerschmidt
• Section for secretory immunity and B cells
  Laboratory for Immunohistochemistry and
  Immunopathology Rikshospitalet University
  Hospital
• Research Center for Infectious Diseases
  University Würzburg Würzburg Germany

2
Streptococcus pneumoniae

• Causes relatively harmless infections like otitis
  media and sinusitis as well as life-threatening
  disease such as pneumonia septicemia and
  meningitis.
• Invades host via nasopharyngeal epithelium.
• A surface-displayed virulence factor SpsA binds
  specifically to SC/pIgR (Hammerschmidt 97 Mol.
  Micorobiol.).
• Invation of nasopharyngeal epithlial cells
  depends on CbpA/SpsA binding to pIgR (Zhang 2000
  Cell).
• CbpA/SpsA interaction with SC/pIgR is specific
  for human SC (Hammerschmidt 2000 Mol.
  Microbiol.).

3
Lumen
Secretory epithelium
As previous
Lamina propria
IgAJ
IgAJ
Plasma cell
4
Binding and internalization of SpsA-coated beads
to pIgR-expressing epithelial cells
5
Binding of human mouse and chimeric SC to SpsA
fragments (SH2 or SH3) and dIgA
dIgA
SH2
SH3
H
H1
H2
H3
H4
H5
M
M1
M2
M3
M4
M5
0
1
2
0.5
1.0
1.5
OD405
OD405
6
Human SC domains D3 and D4 are necessary and
sufficient for SpsA binding when grafted onto
mouse SC
H
M
Hd3
Hd4
Hd3d4
Md3
Md4
0
05
1
15
2
25
OD405
7
Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334  human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t-----------   335   human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445  human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
Domain 4
8
Analysis of SpsA binding of mutants in D3 of
human SC
9
Alignment of human and mouse D3 and D4
Domain 3
Domain 4
10
Analysis of SpsA binding of mutants in D3 of
human SC
11
Analysis of SpsA binding of mutants in D3 of
human SC
H
282-285A
N282A
Q284A
D285A
0
05
1
15
2
25
OD405
12
Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334  human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t-----------   335   human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445  human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
282-285
Domain 4
13
Analysis of SpsA binding of mutants in D4 of
human SC
H
336-339A
347-351A
382-386A
387-390A
0
05
1
15
2
OD405
14
Analysis of SpsA binding of mutants in D4 of
human SC
15
Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334  human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t-----------   335   human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445  human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
N282
Domain 4
W386
16
Conclusions

• SpsA interacts with D3 and D4 in human pIgR/SC.
• Amino acid N282 in D3 is essential for SpsA
  interaction.
• Amino acid W386 in D4 is necessary for SpsA
  interaction.
• This interaction is important in Streptococcus
  pneumoniae pathogenesis.