scholarly journals Design of M protein immunogens to elicit broadly reactive antibodies against Streptococcus pyogenes

2021 ◽  
Author(s):  
Kuei-Chen Wang ◽  
Victor Nizet ◽  
Partho Ghosh
Keyword(s):  
Amino Acids ◽  
Streptococcus Pyogenes ◽  
Three Dimensional ◽  
Bacterial Pathogen ◽  
M Protein ◽  
Vaccine Immunogen ◽  
Protective Response ◽  
Antibody Recognition ◽  
M Proteins ◽  
Virulence Trait

M proteins of the widespread and potentially deadly bacterial pathogen Streptococcus pyogenes (Strep A) are immunodominant targets of opsonizing antibodies. However, the antigenic sequence variability of the M protein into >220 M types has limited its utility as a vaccine immunogen, as antibody recognition is usually type-specific. At present no vaccine against Strep A exists. Unlike type-specific antibodies, C4BP binds type-promiscuously to M proteins. We recently showed that this was due to a three-dimensional (3D) pattern of amino acids that is conserved in numerous M types. We hypothesized that M protein immunogens biased towards the 3D pattern and away from variable sequences would evoke a broadly protective response. We show here that an immunogen containing only 34 amino acids of M2 protein retained C4BP-binding and was sufficient to evoke antibodies that were cross-reactive and opsonophagocytic against multiple M types. These proof-of-principle experiments provide significant evidence that an essential Strep A virulence trait (i.e., C4BP binding) can be targeted in the design of an immunogen that evokes a broadly protective response.

scholarly journals Protective and heart-crossreactive epitopes located within the NH2 terminus of type 19 streptococcal M protein.

1988 ◽  
Vol 167 (6) ◽  
pp. 1849-1859 ◽  
Author(s):  
M S Bronze ◽  
E H Beachey ◽  
J B Dale
Keyword(s):  
Amino Acids ◽  
Heart Disease ◽  
Primary Structure ◽  
Synthetic Peptide ◽  
Human Myocardium ◽  
M Protein ◽  
Streptococcal M Protein ◽  
M Proteins ◽  
Rheumatic Heart

M protein was purified to homogeneity from limited pepsin digests of intact type 19 streptococci (pep M19). The purified pep M19 when emulsified in CFA and injected into rabbits evoked type-specific and crossreactive opsonic antibodies, as well as heart-crossreactive antibodies. The NH2-terminal primary structure of pep M19 was determined and a peptide copying the first 24 amino acids [SM19(1-24)C] was chemically synthesized. Rabbits that were immunized with the unconjugated peptide developed antibodies that recognized the native pep M19, as determined by ELISA, and opsonic antibodies against type 19 streptococci, as determined by in vitro opsonophagocytosis tests. The synthetic peptide also evoked antibodies that crossreacted with a 60-kD sarcolemmal membrane protein of human myocardium. By using overlapping synthetic subpeptides as immunoinhibitors, the opsonic and heart-crossreactive epitopes of SM19(1-24)C were localized to SM19(11-24)C. Our data confirm the presence of heart-crossreactive epitopes within the primary structure of pep M19 and show that these potentially harmful autoimmune epitopes may be located in the NH2-terminal regions of certain M proteins. We conclude that continued efforts to identify the primary structures of protective and heart-crossreactive epitopes will be necessary to elucidate the pathogenesis of acute rheumatic heart disease and to develop safe and effective streptococcal vaccines.

scholarly journals Evasion of Phagocytosis through Cooperation between Two Ligand-binding Regions in Streptococcus pyogenes M Protein

2003 ◽  
Vol 198 (7) ◽  
pp. 1057-1068 ◽  
Author(s):  
Fredric Carlsson ◽  
Karin Berggård ◽  
Margaretha Stålhammar-Carlemalm ◽  
Gunnar Lindahl
Keyword(s):  
Ligand Binding ◽  
Streptococcus Pyogenes ◽  
M Protein ◽  
Classical Pathway ◽  
Human Immune System ◽  
M Proteins ◽  
Binding Regions ◽  
Protective Antibodies ◽  
Bacterial Virulence Factor

The M protein of Streptococcus pyogenes is a major bacterial virulence factor that confers resistance to phagocytosis. To analyze how M protein allows evasion of phagocytosis, we used the M22 protein, which has features typical of many M proteins and has two well-characterized regions binding human plasma proteins: the hypervariable NH2-terminal region binds C4b-binding protein (C4BP), which inhibits the classical pathway of complement activation; and an adjacent semivariable region binds IgA-Fc. Characterization of chromosomal S. pyogenes mutants demonstrated that each of the ligand-binding regions contributed to phagocytosis resistance, which could be fully explained as cooperation between the two regions. Deposition of complement on S. pyogenes occurred almost exclusively via the classical pathway, even under nonimmune conditions, but was down-regulated by bacteria-bound C4BP, providing an explanation for the ability of bound C4BP to inhibit phagocytosis. Different opsonizing antisera shared the ability to block binding of both C4BP and IgA, suggesting that the two regions in M22 play important roles also under immune conditions, as targets for protective antibodies. These data indicate that M22 and similar M proteins confer resistance to phagocytosis through ability to bind two components of the human immune system.

Characterization of group A streptococcal M-proteins purified by two methods

1976 ◽  
Vol 22 (8) ◽  
pp. 1072-1082
Author(s):  
David C. Straus ◽  
Charles F. Lange
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Molecular Size ◽  
M Protein ◽  
M Proteins ◽  
Group A ◽  
Terminal Amino ◽  
High Concentrations

Ten different group A streptococcal M-protein preparations purified by trichloroacetic acid precipitation and three M-protein preparations purified by cellulose chromatography were examined by SDS and polyacrylamide gel electrophoresis, and analyzed for amino acid composition and N-terminal amino acids. Fingerprinting (both tryptic and chymotryptic) was performed on the cellulose-purified preparations of M1, M12, and M29 proteins which showed these proteins to be structurally related. Trypsin produced maps with 37 to 42 peptides, whereas chymotrypsin digestion resulted in 8 to 12 peptides, depending on the M-type. Sequencing was performed on the M12 protein and tentative identification of nine N-terminal amino acids was made. Molecular weights of the cellulose and TCA-purified M-proteins were determined by SDS gel electrophoresis and chromatography on G-200 Sephadex, with comparable results, indicating molecular size of at least 23 000. The amino acid analyses of the 10 TCA-purified proteins followed the patterns established for M-proteins, with high concentrations of lysine, aspartic acid, glutamic acid, alanine, and leucine. All 10 proteins had L-alanine as their N-terminal amino acid. Evidence for a one way cross-reaction between type 1 and type 29 streptococci was also found.

scholarly journals The M Protein of Streptococcus pyogenes Strain AP53 Retains Cell Surface Functional Plasminogen Binding after Inactivation of the Sortase A Gene

2020 ◽  
Vol 202 (10) ◽  
Author(s):  
Brady T. Russo ◽  
Yetunde A. Ayinuola ◽  
Damini Singh ◽  
Katelyn Carothers ◽  
Vincent A. Fischetti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Membrane ◽  
Cell Surface ◽  
Streptococcus Pyogenes ◽  
Cytoplasmic Membrane ◽  
M Protein ◽  
Sortase A ◽  
Content Type ◽  
M Proteins ◽  
Group A

ABSTRACT Streptococcus pyogenes (Lancefield group A Streptococcus [GAS]) is a β-hemolytic human-selective pathogen that is responsible for a large number of morbid and mortal infections in humans. For efficient infection, GAS requires different types of surface proteins that provide various mechanisms for evading human innate immune responses, thus enhancing pathogenicity of the bacteria. Many such virulence-promoting proteins, including the major surface signature M protein, are translocated after biosynthesis through the cytoplasmic membrane and temporarily tethered to this membrane via a type 1 transmembrane domain (TMD) positioned near the COOH terminus. In these proteins, a sorting signal, LPXTG, is positioned immediately upstream of the TMD, which is cleaved by the membrane-associated transpeptidase, sortase A (SrtA), leading to the covalent anchoring of these proteins to newly emerging l-Ala–l-Ala cross-bridges of the growing peptidoglycan cell wall. Herein, we show that inactivation of the srtA gene in a skin-tropic pattern D GAS strain (AP53) results in retention of the M protein in the cell membrane. However, while the isogenic AP53 ΔsrtA strain is attenuated in overall pathogenic properties due to effects on the integrity of the cell membrane, our data show that the M protein nonetheless can extend from the cytoplasmic membrane through the cell wall and then to the surface of the bacteria and thereby retain its important properties of productively binding and activating fluid-phase host plasminogen (hPg). The studies presented herein demonstrate an underappreciated additional mechanism of cell surface display of bacterial virulence proteins via their retention in the cell membrane and extension to the GAS surface. IMPORTANCE Group A Streptococcus pyogenes (GAS) is a human-specific pathogen that produces many surface factors, including its signature M protein, that contribute to its pathogenicity. M proteins undergo specific membrane localization and anchoring to the cell wall via the transpeptidase sortase A. Herein, we explored the role of sortase A function on M protein localization, architecture, and function, employing, a skin-tropic GAS isolate, AP53, which expresses a human plasminogen (hPg)-binding M (PAM) Protein. We showed that PAM anchored in the cell membrane, due to the targeted inactivation of sortase A, was nonetheless exposed on the cell surface and functionally interacted with host hPg. We demonstrate that M proteins, and possibly other sortase A-processed proteins that are retained in the cell membrane, can still function to initiate pathogenic processes by this underappreciated mechanism.

scholarly journals Role of Small Envelope Protein in Sustaining the Intracellular and Extracellular Levels of Hepatitis B Virus Large and Middle Envelope Proteins

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 613
Author(s):  
Jing Zhang ◽  
Yongxiang Wang ◽  
Shuwen Fu ◽  
Quan Yuan ◽  
Qianru Wang ◽  
...  
Keyword(s):  
Envelope Proteins ◽  
Full Length ◽  
M Protein ◽  
Intracellular Level ◽  
S Protein ◽  
L Protein ◽  
M Proteins ◽  
B Virus ◽  
Subviral Particle ◽  
Genotype A

Hepatitis B virus (HBV) expresses co-terminal large (L), middle (M), and small (S) envelope proteins. S protein drives virion and subviral particle secretion, whereas L protein inhibits subviral particle secretion but coordinates virion morphogenesis. We previously found that preventing S protein expression from a subgenomic construct eliminated M protein. The present study further examined impact of S protein on L and M proteins. Mutations were introduced to subgenomic construct of genotype A or 1.1mer replication construct of genotype A or D, and viral proteins were analyzed from transfected Huh7 cells. Mutating S gene ATG to prevent expression of full-length S protein eliminated M protein, reduced intracellular level of L protein despite its blocked secretion, and generated a truncated S protein through translation initiation from a downstream ATG. Truncated S protein was secretion deficient and could inhibit secretion of L, M, S proteins from wild-type constructs. Providing full-length S protein in trans rescued L protein secretion and increased its intracellular level from mutants of lost S gene ATG. Lost core protein expression reduced all the three envelope proteins. In conclusion, full-length S protein could sustain intracellular and extracellular L and M proteins, while truncated S protein could block subviral particle secretion.

scholarly journals Two Overlapping Domains of a Lyssavirus Matrix Protein That Acts on Different Cell Death Pathways

2010 ◽  
Vol 84 (19) ◽  
pp. 9897-9906 ◽  
Author(s):  
Florence Larrous ◽  
Alireza Gholami ◽  
Shahul Mouhamad ◽  
Jérôme Estaquier ◽  
Hervé Bourhy
Keyword(s):  
Cell Death ◽  
Amino Acid ◽  
Matrix Protein ◽  
Full Length ◽  
M Protein ◽  
Genotype 3 ◽  
Cell Death Pathways ◽  
Acid Fragment ◽  
M Proteins ◽  
Cellular Apoptosis

ABSTRACT The lyssavirus matrix (M) protein induces apoptosis. The regions of the M protein that are essential for triggering cell death pathways are not yet clearly defined. We therefore compared the M proteins from two viruses that have contrasting characteristics in terms of cellular apoptosis: a genotype 3 lyssavirus, Mokola virus (MOK), and a genotype 1 rabies virus isolated from a dog from Thailand (THA). We identified a 20-amino-acid fragment (corresponding to positions 67 to 86) that retained the cell death activities of the full-length M protein from MOK via both the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and inhibition of cytochrome c oxidase (CcO) activity. We found that the amino acids at positions 77 and 81 have an essential role in triggering these two cell death pathways. Directed mutagenesis demonstrated that the amino acid at position 77 affects CcO activity, whereas the amino acid at position 81 affects TRAIL-dependent apoptosis. Mutations in the full-length M protein that compromised induction of either of these two pathways resulted in delayed apoptosis compared with the time to apoptosis for the nonmutated control.

scholarly journals Factor H Binds to the Hypervariable Region of Many Streptococcus pyogenes M Proteins but Does Not Promote Phagocytosis Resistance or Acute Virulence

2013 ◽  
Vol 9 (4) ◽  
pp. e1003323 ◽  
Author(s):  
Mattias C. U. Gustafsson ◽  
Jonas Lannergård ◽  
O. Rickard Nilsson ◽  
Bodil M. Kristensen ◽  
John E. Olsen ◽  
...  
Keyword(s):  
Streptococcus Pyogenes ◽  
Hypervariable Region ◽  
Factor H ◽  
M Proteins

scholarly journals Biochemical and biological activity of arginine deiminase from Streptococcus pyogenes M22

2016 ◽  
Vol 94 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eleonora A. Starikova ◽  
Alexey V. Sokolov ◽  
Anna Yu. Vlasenko ◽  
Larisa A. Burova ◽  
Irina S. Freidlin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Group A ◽  
Micro Organisms ◽  
Dose Dependent

Streptococcus pyogenes (group A Streptococcus; GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This micro-organism has developed complex virulence mechanisms to avoid the host’s defenses. We have previously reported that SDSC from GAS type M22 causes endothelial-cell dysfunction, and inhibits cell adhesion, migration, metabolism, and proliferation in a dose-dependent manner, without affecting cell viability. This work aimed to isolate and characterize a component from GAS type M22 supernatant that suppresses the proliferation of endothelial cells (EA.hy926). In the process of isolating a protein possessing antiproliferative activity we identified arginine deiminase (AD). Further study showed that this enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mmol·L–1 and 42 s−1, respectively. A distinctive feature of AD purified from GAS type M22 is that its optimum activity and the maximal rate of the catalytic process is close to neutral pH by comparison with enzymes from other micro-organisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time, in the presence of AD, the proportion of cells in G0/G1 phase increased. When l-Arg was added at increasing concentrations to the culture medium containing AD (3 μg·mL–1), the enzyme’s capacity to inhibit cell proliferation became partially depressed. The proportion of cells in phases S/G2 increased concomitantly, although the cells did not fully recover their proliferation activity. This suggests that AD from GAS type M22 has potential for the suppression of excessive cell proliferation.

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