Heptad motifs within the distal subdomain of the coiled-coil rod region of M protein from rheumatic fever and nephritis associated serotypes of group A streptococci are distinct from each other: Nucleotide sequence of the M57 gene and relation of the deduced amino acid sequence to other M proteins

Manjula, Belur N.; Khandke, Kiran; Fairwell, T; Relf, Wendy A.; Sriprakash, Kadaba S.

doi:10.1007/bf01025251

Cited by 34 publications

(23 citation statements)

References 45 publications

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“…However, the response of PLN cells from rM5-immunized mice to sM5[300-3191 was not detectable, as shown previously, whereas sM5 [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] induced significant responses, as achieved previously with the longer peptide M5[1-35] (28).…”

Section: Resultssupporting

confidence: 61%

“…Groups of BALB/c mice were immunized with synthetic peptides in FCA and boosted with the same peptide in FIA to determine whether T-cell recognition sites within the peptide could provide help for anti-peptide antibody responses. IgG was measured by ELISA in sera from individual mice immunized with sM5[300-319], sM5 [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], or rM5 ( Fig. 6).…”

Section: Resultsmentioning

confidence: 99%

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Characterization of a conserved helper-T-cell epitope from group A Streptococcal M proteins

1993

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We have previously defined major histocompatibility complex (MHC) class II-restricted T-cell epitopes from the carboxy-terminal region of group A streptococcal type 5 M protein. In this report, T-cell responses to one of these epitopes have been characterized in detail. T-cell clones from recombinant M5-immunized mice and popliteal lymph node cells from peptide-immunized mice were used to show that sM5[300-3191 is recognized in the context of I-A alleles of four of nine independent MHC class II haplotypes: I-Ad, I-Af, I-Ak, and I-AS. This epitope was also recognized by both helper (Th2) and inflammatory (Thl) subsets of murine T cells. The I-Ad-restricted epitope recognized by BALB/c mice was mapped to the 12-amino-acid peptide sM5[308-3191 and was shown to provide helper function for an immunoglobulin G anti-peptide antibody response in BALB/c mice. Anti-peptide antibody was shown to be specific for M5[304-3151 but failed to recognize intact rM5, suggesting that the conformation of the epitope differed between peptide and protein. However, the results demonstrate that overlapping epitopes can be the focus for both immunoglobulin G antibodies and the T cells which augment their production. Comparison of the available sequences for M proteins indicated that the T-cell epitope within M5[300-319] was highly conserved between M types and hence may elicit helper function for protective antibody responses to a wide range of M types. T-cell epitopes from conserved regions of M proteins which are recognized in the context of multiple MHC haplotypes have potential for the design of multivalent streptococcal vaccines.

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Section: Resultssupporting

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Characterization of a conserved helper-T-cell epitope from group A Streptococcal M proteins

1993

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“…This association does not seem to be due to a metabolic relationship between enzymes involved in the biotypic delineation and the protein M epitopes. Indeed, it has been demonstrated that the antigenic diversity of protein M is associated with sequence and structure variations of polypeptidic variable regions (5,16). Restricted associations between unrelated phenotypic characteristics within the same species might be explained by different mechanisms.…”

Section: Resultsmentioning

confidence: 99%

Restricted association between biotypes and serotypes within group A streptococci

et al. 1994

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Investigating individual variations between different isolates of group A streptococci, we observed a close correlation between biotypes and serotypes in 46 strains from pharyngitis patients. Biotyping, carried out with a commercially available rapid identification gallery, delineated 10 different associations of characteristics, designated biotypes 1 to 10, observed both in the manufacturer's (127 strains) and our personal (98 strains) collections of group A strains. Only the most frequent biotypes (biotypes 1 to 6) were observed in the pharyngitis cohort, but the overall frequencies of the biotypes did not display striking differences compared with the control collections. Serotyping of the pharyngitis strains showed that each M type was restricted to a sole biotype. For example, M types 1, 4, and 28 were found only in biotype 1 and M type 6 was found only in biotype 6 strains. This association was not due to an epidemiologic bias, since it was also observed in a control series consisting of reference strains and isolates from distant countries (the United States and Czech Republic versus France). An exception was for M type 78, which exhibited biotype 3 or biotype 4. Investigation of the heterogeneity of the strains at the DNA level showed no significant variations of the ribotype patterns between strains of different biotypes, confirming that group A streptococci belong to a unique and homogeneous species. This previously undescribed association between serotypes and biotypes is of interest for a rapid and preliminary characterization of strains isolated in individual patients or during an outbreak. A possible pathogenic association of some biotypic characteristics with specific M proteins is envisaged.Group A streptococci (Streptococcus pyogenes) are the most frequent cause of human pharyngitis (13). This species includes several serotypes which can be specifically involved in acute infections, such as bacteremia and toxic shock-like syndrome, or cause severe complications: nephritis, chorea, and rheumatic fever (12,13,22). Since the 1980s, important changes have arisen in the incidence and clinical features of invasive S. pyogenes infections, and a new emergence of rheumatic fever has been observed all over the world (2,14,17). Recent epidemiological findings have reinforced the interest in this species and led to reassessment of both the efficiency and significance of the methods of strain characterization. The usual classification has been based on antigenic variations of two surface molecules, M protein (15) and T protein (7), and allows delineation between more than 80 and 20 different serotypes, respectively (5); with the presence, or absence, of the serum opacity factor (OF) being correlated with the M protein typing (18).In this study, new typing methods were used to reappraise the homogeneity of the species and to investigate individual variations between different isolates. The S. pyogenes strains are confirmed as belonging to a unique species, with a close correlation between biotypes and serotype...

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“…The exceedingly high predicted a-helical values for the cellular antigens (X = 58 ± 4%) has been noted previously for several of these proteins and has been confirmed by direct structural analysis in a few cases. [19][20][21] The wide fluctuations in DNA base composition among bacteria and between different segments of the eukaryotic genome have most often been attributed to a directional mutation bias that pushes the G and C level of the entire genome or subgenomic segment toward some level.2,3'7,10 By analogy, we suggested that the asymmetrical variation in base frequencies of retroviral genomes arises from directional mutation biases imposed on the genomes when they reside in single-stranded states.13 One line of supporting evidence for this view was the observation that untranslated DNA and silent sites in coding sequences displayed biases that were similar to those that characterized the entire genomes. As shown in Table 2, influenza and tymoviruses display the characteristic biases in the third codon positions of the 4-fold degenerate codons.…”

Section: Resultsmentioning

confidence: 99%

Compositional Similarities between the Human Immunodeficiency Virus and Surface Antigens of Pathogens

Fitzgerald¹,

Bronson²,

Anderson³

1996

AIDS Research and Human Retroviruses

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The genome of the human immunodeficiency virus (HIV) is rich in A but not U and deficient in C but not G. This asymmetric nucleotide bias is the major factor in determining the unusual composition of HIV proteins. In this report, we have identified the cellular genes in the GenBank database that are compositionally similar to HIV in order to further understand the significance of the nucleotide bias of the viral genome. A total of 101 genes in the bacterial and invertebrate subdivisions of the database were found to have a base composition that is similar to the composition of the HIV genome. The identified cellular sequences represent a discrete subset of the database since 81 of the 101 entries code for antigens from pathogens and nearly all of these organisms infect humans. The amino acid compositions of these surface antigens are also similar to the unusual composition of HIV proteins, which are deficient in proline and rich in lysine and other polar residues encoded by A-rich codons. The similarities between the HIV proteins and the immunodominant antigens from other pathogens may indicate a common pathogenic strategy for the promotion of immune dysregulation.

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Heptad motifs within the distal subdomain of the coiled-coil rod region of M protein from rheumatic fever and nephritis associated serotypes of group A streptococci are distinct from each other: Nucleotide sequence of the M57 gene and relation of the deduced amino acid sequence to other M proteins

Cited by 34 publications

References 45 publications

Characterization of a conserved helper-T-cell epitope from group A Streptococcal M proteins

Characterization of a conserved helper-T-cell epitope from group A Streptococcal M proteins

Restricted association between biotypes and serotypes within group A streptococci

Compositional Similarities between the Human Immunodeficiency Virus and Surface Antigens of Pathogens

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