Peptide libraries define the fine specificity of anti-polysaccharide antibodies to Cryptococcus neoformans

Philippe Valadon, Gabriel Nussbaum, Lisa F. Boyd, David H. Margulies, Matthew D. Scharff

Research output: Contribution to journalArticle

124 Citations (Scopus)

Abstract

Cryptococcus neoformans is an encapsulated fungus that causes a life-threatening meningoencephalitis in patients with AIDS. Monoclonal antibodies to the capsular glucuronoxylomannan can modulate the infection in mice, but the epitopes on this complex polysaccharide recognized by protective and non-protective antibodies have not been defined. We have used 2H1, one of our most protective antibodies, to screen phage display peptide libraries for peptide mimotopes that would allow us to explore the fine specificity of anti-cryptococcal polysaccharide antibodies. Hexa- and decapeptides have been identified with sequence homologies that define four motifs: 1, (E)TPXWM/LM/L; 2, W/YXWM/ LYE; 3, DWXDW; and 4, (Ar)WDGQ(Ar). Peptides representing these motifs compete with each other for a shared binding site that overlaps the polysaccharide binding site. Motifs 1 and 2 confer high affinity binding, and PA1, which displays a motif 1 peptide with the sequence LQYTPSWMLV, binds to 2H1 with a K(d) Of 295 nM. Analysis of the interaction between the 2H1 binding peptides and 24 structurally related anti-polysaccharide antibodies reveals a complex pattern of reactivity that strongly suggests binding to or close to the complementary determining regions. Furthermore, those antibodies that have been shown to have different specificity, and in some cases different protective potential, do not bind any of the peptides selected by the protective 2H1 antibody. This study shows that peptide mimotopes for a complex microbial polysaccharide can be identified by screening phage peptide libraries and demonstrates the usefulness of such peptides in analyzing closely related interactive sites of proteins in general and of antibodies in particular.

Original languageEnglish (US)
Pages (from-to)11-22
Number of pages12
JournalJournal of Molecular Biology
Volume261
Issue number1
DOIs
StatePublished - Aug 9 1996

Fingerprint

Peptide Library
Cryptococcus neoformans
Polysaccharides
Anti-Idiotypic Antibodies
Peptides
Antibodies
Lye
Binding Sites
Meningoencephalitis
Sequence Homology
Bacteriophages
Epitopes
Acquired Immunodeficiency Syndrome
Fungi
Monoclonal Antibodies
Infection

Keywords

  • Antibody
  • Cryptococcus
  • Peptide library
  • Phage
  • Polysaccharide

ASJC Scopus subject areas

  • Virology

Cite this

Peptide libraries define the fine specificity of anti-polysaccharide antibodies to Cryptococcus neoformans. / Valadon, Philippe; Nussbaum, Gabriel; Boyd, Lisa F.; Margulies, David H.; Scharff, Matthew D.

In: Journal of Molecular Biology, Vol. 261, No. 1, 09.08.1996, p. 11-22.

Research output: Contribution to journalArticle

Valadon, Philippe ; Nussbaum, Gabriel ; Boyd, Lisa F. ; Margulies, David H. ; Scharff, Matthew D. / Peptide libraries define the fine specificity of anti-polysaccharide antibodies to Cryptococcus neoformans. In: Journal of Molecular Biology. 1996 ; Vol. 261, No. 1. pp. 11-22.
@article{604e203ef8a04becaae59910e833494d,
title = "Peptide libraries define the fine specificity of anti-polysaccharide antibodies to Cryptococcus neoformans",
abstract = "Cryptococcus neoformans is an encapsulated fungus that causes a life-threatening meningoencephalitis in patients with AIDS. Monoclonal antibodies to the capsular glucuronoxylomannan can modulate the infection in mice, but the epitopes on this complex polysaccharide recognized by protective and non-protective antibodies have not been defined. We have used 2H1, one of our most protective antibodies, to screen phage display peptide libraries for peptide mimotopes that would allow us to explore the fine specificity of anti-cryptococcal polysaccharide antibodies. Hexa- and decapeptides have been identified with sequence homologies that define four motifs: 1, (E)TPXWM/LM/L; 2, W/YXWM/ LYE; 3, DWXDW; and 4, (Ar)WDGQ(Ar). Peptides representing these motifs compete with each other for a shared binding site that overlaps the polysaccharide binding site. Motifs 1 and 2 confer high affinity binding, and PA1, which displays a motif 1 peptide with the sequence LQYTPSWMLV, binds to 2H1 with a K(d) Of 295 nM. Analysis of the interaction between the 2H1 binding peptides and 24 structurally related anti-polysaccharide antibodies reveals a complex pattern of reactivity that strongly suggests binding to or close to the complementary determining regions. Furthermore, those antibodies that have been shown to have different specificity, and in some cases different protective potential, do not bind any of the peptides selected by the protective 2H1 antibody. This study shows that peptide mimotopes for a complex microbial polysaccharide can be identified by screening phage peptide libraries and demonstrates the usefulness of such peptides in analyzing closely related interactive sites of proteins in general and of antibodies in particular.",
keywords = "Antibody, Cryptococcus, Peptide library, Phage, Polysaccharide",
author = "Philippe Valadon and Gabriel Nussbaum and Boyd, {Lisa F.} and Margulies, {David H.} and Scharff, {Matthew D.}",
year = "1996",
month = "8",
day = "9",
doi = "10.1006/jmbi.1996.0438",
language = "English (US)",
volume = "261",
pages = "11--22",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - Peptide libraries define the fine specificity of anti-polysaccharide antibodies to Cryptococcus neoformans

AU - Valadon, Philippe

AU - Nussbaum, Gabriel

AU - Boyd, Lisa F.

AU - Margulies, David H.

AU - Scharff, Matthew D.

PY - 1996/8/9

Y1 - 1996/8/9

N2 - Cryptococcus neoformans is an encapsulated fungus that causes a life-threatening meningoencephalitis in patients with AIDS. Monoclonal antibodies to the capsular glucuronoxylomannan can modulate the infection in mice, but the epitopes on this complex polysaccharide recognized by protective and non-protective antibodies have not been defined. We have used 2H1, one of our most protective antibodies, to screen phage display peptide libraries for peptide mimotopes that would allow us to explore the fine specificity of anti-cryptococcal polysaccharide antibodies. Hexa- and decapeptides have been identified with sequence homologies that define four motifs: 1, (E)TPXWM/LM/L; 2, W/YXWM/ LYE; 3, DWXDW; and 4, (Ar)WDGQ(Ar). Peptides representing these motifs compete with each other for a shared binding site that overlaps the polysaccharide binding site. Motifs 1 and 2 confer high affinity binding, and PA1, which displays a motif 1 peptide with the sequence LQYTPSWMLV, binds to 2H1 with a K(d) Of 295 nM. Analysis of the interaction between the 2H1 binding peptides and 24 structurally related anti-polysaccharide antibodies reveals a complex pattern of reactivity that strongly suggests binding to or close to the complementary determining regions. Furthermore, those antibodies that have been shown to have different specificity, and in some cases different protective potential, do not bind any of the peptides selected by the protective 2H1 antibody. This study shows that peptide mimotopes for a complex microbial polysaccharide can be identified by screening phage peptide libraries and demonstrates the usefulness of such peptides in analyzing closely related interactive sites of proteins in general and of antibodies in particular.

AB - Cryptococcus neoformans is an encapsulated fungus that causes a life-threatening meningoencephalitis in patients with AIDS. Monoclonal antibodies to the capsular glucuronoxylomannan can modulate the infection in mice, but the epitopes on this complex polysaccharide recognized by protective and non-protective antibodies have not been defined. We have used 2H1, one of our most protective antibodies, to screen phage display peptide libraries for peptide mimotopes that would allow us to explore the fine specificity of anti-cryptococcal polysaccharide antibodies. Hexa- and decapeptides have been identified with sequence homologies that define four motifs: 1, (E)TPXWM/LM/L; 2, W/YXWM/ LYE; 3, DWXDW; and 4, (Ar)WDGQ(Ar). Peptides representing these motifs compete with each other for a shared binding site that overlaps the polysaccharide binding site. Motifs 1 and 2 confer high affinity binding, and PA1, which displays a motif 1 peptide with the sequence LQYTPSWMLV, binds to 2H1 with a K(d) Of 295 nM. Analysis of the interaction between the 2H1 binding peptides and 24 structurally related anti-polysaccharide antibodies reveals a complex pattern of reactivity that strongly suggests binding to or close to the complementary determining regions. Furthermore, those antibodies that have been shown to have different specificity, and in some cases different protective potential, do not bind any of the peptides selected by the protective 2H1 antibody. This study shows that peptide mimotopes for a complex microbial polysaccharide can be identified by screening phage peptide libraries and demonstrates the usefulness of such peptides in analyzing closely related interactive sites of proteins in general and of antibodies in particular.

KW - Antibody

KW - Cryptococcus

KW - Peptide library

KW - Phage

KW - Polysaccharide

UR - http://www.scopus.com/inward/record.url?scp=0030576498&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030576498&partnerID=8YFLogxK

U2 - 10.1006/jmbi.1996.0438

DO - 10.1006/jmbi.1996.0438

M3 - Article

C2 - 8760499

AN - SCOPUS:0030576498

VL - 261

SP - 11

EP - 22

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

SN - 0022-2836

IS - 1

ER -