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An integrated approach to epitope analysis II: A system for proteomic-scale prediction of immunological characteristics.

Bremel RD, Homan EJ - Immunome Res (2010)

Bottom Line: These are characterized as coincident epitope groups (CEGs).A desktop application with interactive graphic capability is shown to be a useful platform for development of prediction and visualization tools for epitope mapping at scales ranging from individual proteins to proteomes from multiple strains of an organism.The possible functional implications of the patterns of peptide epitopes observed are discussed, including their implications for B-cell and T-cell cooperation and cross presentation.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1ioGenetics LLC, 3591 Anderson Street, Madison, WI 53704, USA. robert_bremel@iogenetics.com.

ABSTRACT

Background: Improving our understanding of the immune response is fundamental to developing strategies to combat a wide range of diseases. We describe an integrated epitope analysis system which is based on principal component analysis of sequences of amino acids, using a multilayer perceptron neural net to conduct QSAR regression predictions for peptide binding affinities to 35 MHC-I and 14 MHC-II alleles.

Results: The approach described allows rapid processing of single proteins, entire proteomes or subsets thereof, as well as multiple strains of the same organism. It enables consideration of the interface of diversity of both microorganisms and of host immunogenetics. Patterns of binding affinity are linked to topological features, such as extracellular or intramembrane location, and integrated into a graphical display which facilitates conceptual understanding of the interplay of B-cell and T-cell mediated immunity.Patterns which emerge from application of this approach include the correlations between peptides showing high affinity binding to MHC-I and to MHC-II, and also with predicted B-cell epitopes. These are characterized as coincident epitope groups (CEGs). Also evident are long range patterns across proteins which identify regions of high affinity binding for a permuted population of diverse and heterozygous HLA alleles, as well as subtle differences in reactions with MHCs of individual HLA alleles, which may be important in disease susceptibility, and in vaccine and clinical trial design. Comparisons are shown of predicted epitope mapping derived from application of the QSAR approach with experimentally derived epitope maps from a diverse multi-species dataset, from Staphylococcus aureus, and from vaccinia virus.

Conclusions: A desktop application with interactive graphic capability is shown to be a useful platform for development of prediction and visualization tools for epitope mapping at scales ranging from individual proteins to proteomes from multiple strains of an organism. The possible functional implications of the patterns of peptide epitopes observed are discussed, including their implications for B-cell and T-cell cooperation and cross presentation.

No MeSH data available.


Related in: MedlinePlus

Example of long range variation in mean MHC II affinity across a single protein (Thermonuclease precursor Staphylococcus aureus COL gi 57650135). (A) DRB4*0101 and (B) DRB1*0404 have a high correlation (r = 0.6) while (C) DRB3*0101 and (D) DRB1*0901 have a low correlation.
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Figure 3: Example of long range variation in mean MHC II affinity across a single protein (Thermonuclease precursor Staphylococcus aureus COL gi 57650135). (A) DRB4*0101 and (B) DRB1*0404 have a high correlation (r = 0.6) while (C) DRB3*0101 and (D) DRB1*0901 have a low correlation.

Mentions: By examining the plots of many different proteins with different types of data portrayal we observed that, despite individual 15-mer peptides showing widely different predicted binding affinities for the different MHC supertypes, there was a tendency for high binding for all supertypes to locate in certain regions of molecules and low binding in other regions. This can be seen by undulations in the averaged mean affinities across a protein sequence. Not only was this the case among MHC-II supertypes, but was also seen with the overall means of all MHC-I and MHC-II supertypes (Figure 3; Table 4). After examining many different proteins individually it emerged that each protein has a characteristic undulation pattern regardless of the supertype or MHC. Computed on an affinity basis the variations are very large with the mean affinity varying over a thousand-fold for peptides from different regions within a protein molecule. This long-range variation is superimposed on a large peptide to peptide variation within the protein.


An integrated approach to epitope analysis II: A system for proteomic-scale prediction of immunological characteristics.

Bremel RD, Homan EJ - Immunome Res (2010)

Example of long range variation in mean MHC II affinity across a single protein (Thermonuclease precursor Staphylococcus aureus COL gi 57650135). (A) DRB4*0101 and (B) DRB1*0404 have a high correlation (r = 0.6) while (C) DRB3*0101 and (D) DRB1*0901 have a low correlation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2991286&req=5

Figure 3: Example of long range variation in mean MHC II affinity across a single protein (Thermonuclease precursor Staphylococcus aureus COL gi 57650135). (A) DRB4*0101 and (B) DRB1*0404 have a high correlation (r = 0.6) while (C) DRB3*0101 and (D) DRB1*0901 have a low correlation.
Mentions: By examining the plots of many different proteins with different types of data portrayal we observed that, despite individual 15-mer peptides showing widely different predicted binding affinities for the different MHC supertypes, there was a tendency for high binding for all supertypes to locate in certain regions of molecules and low binding in other regions. This can be seen by undulations in the averaged mean affinities across a protein sequence. Not only was this the case among MHC-II supertypes, but was also seen with the overall means of all MHC-I and MHC-II supertypes (Figure 3; Table 4). After examining many different proteins individually it emerged that each protein has a characteristic undulation pattern regardless of the supertype or MHC. Computed on an affinity basis the variations are very large with the mean affinity varying over a thousand-fold for peptides from different regions within a protein molecule. This long-range variation is superimposed on a large peptide to peptide variation within the protein.

Bottom Line: These are characterized as coincident epitope groups (CEGs).A desktop application with interactive graphic capability is shown to be a useful platform for development of prediction and visualization tools for epitope mapping at scales ranging from individual proteins to proteomes from multiple strains of an organism.The possible functional implications of the patterns of peptide epitopes observed are discussed, including their implications for B-cell and T-cell cooperation and cross presentation.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1ioGenetics LLC, 3591 Anderson Street, Madison, WI 53704, USA. robert_bremel@iogenetics.com.

ABSTRACT

Background: Improving our understanding of the immune response is fundamental to developing strategies to combat a wide range of diseases. We describe an integrated epitope analysis system which is based on principal component analysis of sequences of amino acids, using a multilayer perceptron neural net to conduct QSAR regression predictions for peptide binding affinities to 35 MHC-I and 14 MHC-II alleles.

Results: The approach described allows rapid processing of single proteins, entire proteomes or subsets thereof, as well as multiple strains of the same organism. It enables consideration of the interface of diversity of both microorganisms and of host immunogenetics. Patterns of binding affinity are linked to topological features, such as extracellular or intramembrane location, and integrated into a graphical display which facilitates conceptual understanding of the interplay of B-cell and T-cell mediated immunity.Patterns which emerge from application of this approach include the correlations between peptides showing high affinity binding to MHC-I and to MHC-II, and also with predicted B-cell epitopes. These are characterized as coincident epitope groups (CEGs). Also evident are long range patterns across proteins which identify regions of high affinity binding for a permuted population of diverse and heterozygous HLA alleles, as well as subtle differences in reactions with MHCs of individual HLA alleles, which may be important in disease susceptibility, and in vaccine and clinical trial design. Comparisons are shown of predicted epitope mapping derived from application of the QSAR approach with experimentally derived epitope maps from a diverse multi-species dataset, from Staphylococcus aureus, and from vaccinia virus.

Conclusions: A desktop application with interactive graphic capability is shown to be a useful platform for development of prediction and visualization tools for epitope mapping at scales ranging from individual proteins to proteomes from multiple strains of an organism. The possible functional implications of the patterns of peptide epitopes observed are discussed, including their implications for B-cell and T-cell cooperation and cross presentation.

No MeSH data available.


Related in: MedlinePlus