The two variants of the Streptococcus pneumoniae pilus 1 RrgA adhesin retain the same function and elicit cross-protection in vivo.
Thirty percent of Streptococcus pneumoniae isolates contain pilus islet 1, coding for a pilus composed of the backbone subunit RrgB and two ancillary proteins, RrgA and RrgC. RrgA is the major determinant of in vitro adhesion associated with pilus 1, is protective in vivo in mouse models, and exists in two variants (clades I and II). Mapping of the sequence variability onto the RrgA structure predicted from X-ray data showed that the diversity was restricted to the "head" of the protein, which contains the putative binding domains, whereas the elongated "stalk" was mostly conserved. To investigate whether this variability could influence the adhesive capacity of RrgA and to map the regions important for binding, two full-length protein variants and three recombinant RrgA portions were tested for adhesion to lung epithelial cells and to purified extracellular matrix (ECM) components. The two RrgA variants displayed similar binding abilities, whereas none of the recombinant fragments adhered at levels comparable to those of the full-length protein, suggesting that proper folding and structural arrangement are crucial to retain protein functionality. Furthermore, the two RrgA variants were shown to be cross-reactive in vitro and cross-protective in vivo in a murine model of passive immunization. Taken together, these data indicate that the region implicated in adhesion and the functional epitopes responsible for the protective ability of RrgA may be conserved and that the considerable level of variation found within the "head" domain of RrgA may have been generated by immunologic pressure without impairing the functional integrity of the pilus.
Moschioni
Monica
M
Novartis Vaccines and Diagnostics, Via Fiorentina, Siena 53100, Italy.
Emolo
Carla
C
Biagini
Massimiliano
M
Maccari
Silvia
S
Pansegrau
Werner
W
Donati
Claudio
C
Hilleringmann
Markus
M
Ferlenghi
Ilaria
I
Ruggiero
Paolo
P
Sinisi
Antonia
A
Pizza
Mariagrazia
M
Norais
Nathalie
N
Barocchi
Michèle A
MA
Masignani
Vega
V
D018829:Adhesins, Bacterial / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D056738:Cross Protection / Q000235:genetics / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000502:physiology*; D005434:Flow Cytometry; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics / Q000502:physiology; D007116:Immunization, Passive; D051379:Mice; D008807:Mice, Inbred BALB C; D011008:Pneumococcal Infections / Q000382:microbiology; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D011994:Recombinant Proteins / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology
D018829:Adhesins, Bacterial; D011994:Recombinant Proteins
J Immunol. 2009 Aug 1;183(3):1952-63
19570831
Laryngoscope. 2000 Jun;110(6):961-4
10852513
Lancet Infect Dis. 2010 Jan;10(1):32-42
20129147
Biochemistry. 2009 Nov 10;48(44):10549-57
19810750
Vaccine. 2007 Mar 22;25(13):2507-12
17011085
J Biol Chem. 2010 Mar 5;285(10):7517-24
20048164
Clin Microbiol Infect. 2009 Nov;15(11):1039-45
19694764
Expert Rev Vaccines. 2006 Oct;5(5):651-67
17181439
J Cell Biol. 1989 Jul;109(1):409-20
2663881
Pediatrics. 2009 Jul;124(1):e1-11
19564254
Pediatr Infect Dis J. 2009 Oct;28(10 Suppl):S133-7
19918136
Clin Microbiol Infect. 2010 Sep;16(9):1501-4
19886901
J Biol Chem. 2009 Jul 31;284(31):20729-37
19497855
Mol Microbiol. 2003 Nov;50(4):1429-38
14622427
Science. 2005 Jul 1;309(5731):105
15994549
Cochrane Database Syst Rev. 2009 Oct 07;(4):CD004977
19821336
Mol Microbiol. 2006 Jun;60(6):1401-13
16796677
BMC Microbiol. 2008 Feb 28;8:41
18307767
Future Microbiol. 2008 Feb;3(1):23-30
18230031
J Infect Dis. 2008 Mar 15;197(6):888-96
18269316
Infect Immun. 2007 Feb;75(2):1059-62
17145945
Lancet. 2009 Sep 12;374(9693):893-902
19748398
Nat Rev Microbiol. 2006 Jul;4(7):509-19
16778837
Structure. 2010 Jan 13;18(1):106-15
20152157
PLoS Pathog. 2008 Mar 21;4(3):e1000026
18369475
J Infect Dis. 2002 Apr 1;185(7):927-36
11920317
EMBO J. 2009 Dec 16;28(24):3921-30
19942854
Lancet. 2009 Oct 31;374(9700):1543-56
19880020
J Infect Dis. 2008 Aug 1;198(3):375-83
18507531
Proc Natl Acad Sci U S A. 2006 Feb 21;103(8):2857-62
16481624
Protein Eng. 1992 Apr;5(3):191-5
1409538
J Biol Chem. 2010 Apr 16;285(16):12405-15
20147289
J Biol Chem. 1998 Apr 24;273(17):10396-401
9553097
Proc Natl Acad Sci U S A. 2009 Nov 24;106(47):19992-7
19903875
J Infect Dis. 2008 Sep 15;198(6):890-8
18694342
Curr Opin Otolaryngol Head Neck Surg. 2004 Dec;12(6):488-94
15548905
PLoS One. 2008;3(11):e3660
18987753
J Infect Dis. 2007 Oct 15;196(8):1221-7
17955441
J Exp Med. 2009 Aug 31;206(9):1845-52
19687228
Vaccine. 2009 Jun 12;27(29):3831-7
19490983
Microb Pathog. 2007 May-Jun;42(5-6):225-36
17412553
J Bacteriol. 2008 Aug;190(15):5480-92
18515415
J Infect Dis. 2002 Dec 1;186(11):1608-14
12447737
Mol Microbiol. 2007 Oct;66(2):329-40
17850254
J Clin Microbiol. 2007 Jun;45(6):1684-9
17392439
BMC Infect Dis. 2010 Apr 08;10:90
20377886
Cell Microbiol. 2007 Jul;9(7):1822-33
17359232
Mol Microbiol. 2007 May;64(4):968-83
17501921
J Biol Chem. 1997 Nov 7;272(45):28512-7
9353312
Adv Exp Med Biol. 2009;634:121-8
19280854
Proc Natl Acad Sci U S A. 2009 Oct 6;106(40):16967-71
19805181
Am J Epidemiol. 2010 Jan 15;171(2):169-76
19969530
Trends Microbiol. 2004 May;12(5):228-34
15120142
Vaccine. 2009 Aug 21;27 Suppl 3:C22-4
19545935
J Biol Chem. 2005 Aug 19;280(33):29393-6
15998637