scholarly journals Identification of Murine B-Cell and T-Cell Epitopes of Escherichia coli Outer Membrane Protein F with Synthetic Polypeptides

2000 ◽  
Vol 68 (5) ◽  
pp. 2535-2545 ◽  
Author(s):  
Kristina M. Williams ◽  
Elmer C. Bigley ◽  
Richard B. Raybourne
Keyword(s):  
Escherichia Coli ◽  
T Cell ◽  
B Cell ◽  
Outer Membrane ◽  
Synthetic Peptides ◽  
Outer Membrane Proteins ◽  
T Cell Epitopes ◽  
Native Protein ◽  
Cell Responses ◽  
Synthetic Polypeptides

ABSTRACT The major pore-forming outer membrane proteins (Omps) of gram-negative bacteria demonstrate numerous immunomodulating properties and are involved in the virulence of pathogenic strains. BecauseEscherichia coli OmpF is the best-characterized porin in terms of structural and functional characteristics, in vitro B-cell and T-cell responses to this porin in six different strains of mice were analyzed. Mice were immunized with purified OmpF trimers or overlapping synthetic polypeptides (20-mers) spanning the entire 340-amino-acid sequence of the OmpF monomer. T-cell proliferative responses and immunoglobulin G antibody responses to native OmpF and the peptide analogues were determined. For each strain, patterns of T-cell proliferation were similar regardless of whether native OmpF or synthetic peptides were inoculated, although all strains recognized one or more cryptic determinants. Mice exhibited several haplotype-specific responses, but genetically permissive epitopes were also identified. Four peptides (75-94, 265-284, 295-314, and 305-324) elicited strong T-cell proliferative responses from all strains of mice when mice were presensitized with native OmpF or a homologous peptide. In general, 10 or fewer peptides were recognized by sera from mice immunized with native OmpF or synthetic peptides, and most sera from peptide-immunized mice reacted poorly with the native protein. Four peptides spanning amino acids 45 to 64, 95 to 114, 115 to 134, and 275 to 294 were recognized by sera from all strains immunized with native OmpF but not by sera from peptide-immunized mice. Peptides 245-264 and 305-324 were universally recognized by sera from peptide-immunized mice, but these sera reacted weakly or were negative when tested against the native protein. Based on the pattern of cytokine secretion by proliferating T cells, immunization with native OmpF polarizes T helper cells toward development of a TH1 response. T-cell and B-cell responses have been investigated based on the assumption that differences in epitope specificity could influence protective or pathologic host reactions. Because of the high level of structural homology of OmpF to porins isolated from other enteric pathogens, the identification of T- and B-cell-stimulatory determinants of E. coli OmpF may have broader application.

scholarly journals CD4 T-Cell Epitopes Associated with Protective Immunity Induced following Vaccination of Mice with an Ehrlichial Variable Outer Membrane Protein

2007 ◽  
Vol 75 (11) ◽  
pp. 5453-5459 ◽  
Author(s):  
Bisweswar Nandi ◽  
Kathryn Hogle ◽  
Nicholas Vitko ◽  
Gary M. Winslow
Keyword(s):  
T Cell ◽  
Outer Membrane ◽  
Protective Immunity ◽  
Outer Membrane Proteins ◽  
T Cell Responses ◽  
Cd4 T Cell ◽  
T Cell Epitopes ◽  
Heterologous Immunity ◽  
Cell Responses ◽  
Ifn Γ

ABSTRACT The ehrlichiae express variable outer membrane proteins (OMPs) that play important roles in both pathogenesis and host defense. Previous studies revealed that OMPs are immunodominant B-cell antigens and that passive transfer of anti-OMP antibodies can protect SCID mice from fatal ehrlichial infection. In this study, we used a model of fatal monocytotropic ehrlichiosis caused by Ehrlichia bacteria from Ixodes ovatus (IOE) to determine whether OMP immunization could generate protective immunity in immunocompetent mice. Immunization of C57BL/6 mice with a purified recombinant OMP expressed by IOE omp19 generated protection from fatal IOE infection and elicited robust humoral and CD4 T-cell responses. To identify CD4 T-cell epitopes within OMPs, we performed enzyme-linked immunospot analyses for gamma interferon (IFN-γ) production using a panel of overlapping 16-mer peptides from IOE OMP-19. Five immunoreactive peptides comprising residues 30 to 45, 77 to 92, 107 to 122, 197 to 212, and 247 to 264 were identified; the strongest response was generated against OMP-19107-122. Most of the peptides are conserved between E. muris and E. chaffeensis OMP-19, and they elicited IFN-γ production in CD4 T cells from E. muris-infected mice, indicating that T-cell epitope cross-reactivity likely contributes to heterologous immunity. Accordingly, CD4 T-cell responses to both OMP-19 and OMP-19107-122 were of greater magnitude following high-dose IOE challenge of mice that had been immunized by prior infection with E. muris. Our studies cumulatively identify B- and T-cell epitopes that are associated with protective homologous and heterologous immunity during ehrlichial infection.

scholarly journals Enhanced T- and B-cell responses to simian immunodeficiency virus (SIV)agm, SIVmac and human immunodeficiency virus type 1 Gag DNA immunization and identification of novel T-cell epitopes in mice via codon optimization

2009 ◽  
Vol 90 (10) ◽  
pp. 2513-2518 ◽  
Author(s):  
Christine S. Siegismund ◽  
Oliver Hohn ◽  
Reinhard Kurth ◽  
Stephen Norley
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
B Cell ◽  
Simian Immunodeficiency Virus ◽  
Codon Optimization ◽  
T Cell Epitopes ◽  
Gm Csf ◽  
Cell Responses ◽  
Immunodeficiency Virus

As a prelude to primate studies, the immunogenicity of wild-type and codon-optimized versions of simian immunodeficiency virus (SIV)agm Gag DNA, with and without co-administered granulocyte–macrophage colony-stimulating factor (GM-CSF) DNA, was directly compared in two strains of mice. Gag-specific T cells in the splenocytes of BALB/c and C57BL/6 mice immunized by gene gun were quantified by ELISpot using panels of overlapping synthetic peptides (15mers) spanning the entire capsid proteins of SIVagm, SIVmac and human immunodeficiency virus type 1. Specific antibodies were measured by ELISA. Codon optimization was shown to significantly increase the immune response to the DNA immunogens, reducing the amount of DNA necessary to induce cellular and antibody responses by one and two orders of magnitude, respectively. Co-administration of murine GM-CSF DNA was necessary for the induction of high level T- and B-cell responses. Finally, it was possible to identify both known and novel T-cell epitopes in the Gag proteins of the three viruses.

Murine cross-reactive T-cell epitopes of Neisseria meningitidis outer membrane proteins

Vaccine ◽  
1992 ◽  
Vol 10 (3) ◽  
pp. 159-163 ◽  
Author(s):  
M.Robert Lifely ◽  
Mark V. Rogers ◽  
Jane Esdaile ◽  
Michael Payne ◽  
John P. Tite
Keyword(s):  
T Cell ◽  
Membrane Proteins ◽  
Neisseria Meningitidis ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
T Cell Epitopes

scholarly journals Physical Linkage of Naturally Complexed Bacterial Outer Membrane Proteins Enhances Immunogenicity

2007 ◽  
Vol 76 (3) ◽  
pp. 1223-1229 ◽  
Author(s):  
Henriette Macmillan ◽  
Junzo Norimine ◽  
Kelly A. Brayton ◽  
Guy H. Palmer ◽  
Wendy C. Brown
Keyword(s):  
T Cell ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Surface Protein ◽  
Host Cells ◽  
Effective Vaccine ◽  
T Cell Epitopes ◽  
Carrier Effect ◽  
Major Surface

ABSTRACTThe outer membrane proteins (OMPs) of bacterial pathogens are essential for their growth and survival and especially for attachment and invasion of host cells. Since the outer membrane is the interface between the bacterium and the host cell, outer membranes and individual OMPs are targeted for development of vaccines against many bacterial diseases. Whole outer membrane fractions often protect against disease, and this protection cannot be fully reproduced by using individual OMPs. Exactly how the interactions among individual OMPs influence immunity is not well understood. We hypothesized that one OMP rich in T-cell epitopes can act as a carrier for an associated OMP which is poor in T-cell epitopes to generate T-dependent antibody responses, similar to the hapten-carrier effect. Major surface protein 1a (MSP1a) and MSP1b1 occur as naturally complexed OMPs in theAnaplasma marginaleouter membrane. Previous studies demonstrated that immunization with the native MSP1 heteromer induced strong immunoglobulin G (IgG) responses to both proteins, but only MSP1a stimulated strong CD4+T-cell responses. Therefore, to test our hypothesis, constructs of CD4+T-cell epitopes from MSP1a linked to MSP1b1 were compared with individually administered MSP1a and MSP1b1 for induction of MSP1b-specific IgG. By linking the T-cell epitopes from MSP1a to MSP1b1, significantly higher IgG titers against MSP1b1 were induced. Understanding how the naturally occurring intermolecular interactions between OMPs influence the immune response may lead to more effective vaccine design.

Mapping of the immunodominant B- and T-cell epitopes of the outer membrane protein P1 of H. influenzae type b using overlapping synthetic peptides

Peptides ◽  
1992 ◽  
pp. 697-698
Author(s):  
Pele C. S. Chong ◽  
Gloria Zobrist ◽  
Yan-Ping Yang ◽  
Raafat Fahim ◽  
Charles Sia ◽  
...  
Keyword(s):  
T Cell ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Synthetic Peptides ◽  
T Cell Epitopes ◽  
Type B

Unraveling the Danger Signal Necessary for the Immune Response to Therapeutic Factor VIII.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1220-1220
Author(s):  
Jonathan Skupsky ◽  
Ai-Hong Zhang ◽  
David W. Scott
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Factor Viii ◽  
B Cell ◽  
T Cell Responses ◽  
Foreign Protein ◽  
Antibody Concentration ◽  
T Cell Epitopes ◽  
Danger Signal ◽  
Cell Responses

Abstract It is well established that mice which do not produce endogenous factor VIII (fVIII−/−) can manifest a robust immune response to exogenous fVIII treatments. They form B-cell and T-cell responses even when they encounter fVIII through traditionally tolerogenic routes (e.g., intravenous or intraperitoneal). In the fVIII−/− mouse, repeated administration of recombinant human fVIII has emerged as a useful model for studying the physiologic response in hemophilic patients iatrogenically immunized to therapeutic factor VIII treatments. While environmental factors likely offer some co-stimulatory signals, nonetheless, the ability to respond effectively in the absence of extrinsic adjuvant begs the questions of what is the “danger signal” required for immune responsiveness to fVIII? We have previously shown that when factor VIII is heat inactivated (56°, 30′), it completely losses function and much of its immunogenicity (Skupsky and Scott, Blood110: 2685 Abstract, 2007). Heated fVIII lacks several of its B-cell epitopes (we did not find a subsequent response to neo-epitopes), but retains its T-cell epitopes. We concluded that fVIII’s immunogenicity is inherently tied to its function. To explore this topic further, we have immunized hemophilic mice with rfVIII and compared the response to mice treated with both rfVIII and Hirudin. Hirudin is the reactive agent found in medicinal leech saliva and its anti-coagulant activity is based on its ability to inhibit thrombin. We found that T cell responses to rfVIII in mice protected with Hirudin are significantly reduced (p<0.05) and the anti-fVIII antibody concentration has decreased by 25%. As a control, we injected a third group of mice i.v. with an equivalent amount of another foreign protein, ovalbumin (OVA) in PBS. As expected, the mice did not respond to this historically tolerogenic treatment. Interestingly, when mice were injected simultaneously with rfVIII and OVA, they did form a humoral response to both the fVIII (200 μg/ml) and the OVA (30μg/ml). This suggests that fVIII may have adjuvant properties remaining to be discovered. Overall, these data suggest that the activation of thrombin provides co-stimulatory signals necessary for the immune response. Activated thrombin does this directly or indirectly through the activation of other blood components, including platelets.

Different B-cell responses to human T-cell lymphotropic virus type I (HTLV-I) envelope synthetic peptides in HTLV-I-infected individuals

1991 ◽  
Vol 11 (3) ◽  
pp. 143-151 ◽  
Author(s):  
Hiroaki Ida ◽  
Akihiko Kurata ◽  
Katsumi Eguchi ◽  
Atsushi Kawakami ◽  
Kiyoshi Migita ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Virus Type ◽  
Synthetic Peptides ◽  
Type I ◽  
Cell Responses ◽  
Human T Cell ◽  
B Cell Responses

scholarly journals Landscape and selection of vaccine epitopes in SARS-CoV-2

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Christof C. Smith ◽  
Kelly S. Olsen ◽  
Kaylee M. Gentry ◽  
Maria Sambade ◽  
Wolfgang Beck ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Cell Epitope ◽  
T Cell Responses ◽  
Sequence Conservation ◽  
Conformational Space ◽  
T Cell Epitope ◽  
T Cell Epitopes ◽  
Cell Responses ◽  
B Cell Epitope

Abstract Background Early in the pandemic, we designed a SARS-CoV-2 peptide vaccine containing epitope regions optimized for concurrent B cell, CD4+ T cell, and CD8+ T cell stimulation. The rationale for this design was to drive both humoral and cellular immunity with high specificity while avoiding undesired effects such as antibody-dependent enhancement (ADE). Methods We explored the set of computationally predicted SARS-CoV-2 HLA-I and HLA-II ligands, examining protein source, concurrent human/murine coverage, and population coverage. Beyond MHC affinity, T cell vaccine candidates were further refined by predicted immunogenicity, sequence conservation, source protein abundance, and coverage of high frequency HLA alleles. B cell epitope regions were chosen from linear epitope mapping studies of convalescent patient serum, followed by filtering for surface accessibility, sequence conservation, spatial localization near functional domains of the spike glycoprotein, and avoidance of glycosylation sites. Results From 58 initial candidates, three B cell epitope regions were identified. From 3730 (MHC-I) and 5045 (MHC-II) candidate ligands, 292 CD8+ and 284 CD4+ T cell epitopes were identified. By combining these B cell and T cell analyses, as well as a manufacturability heuristic, we proposed a set of 22 SARS-CoV-2 vaccine peptides for use in subsequent murine studies. We curated a dataset of ~ 1000 observed T cell epitopes from convalescent COVID-19 patients across eight studies, showing 8/15 recurrent epitope regions to overlap with at least one of our candidate peptides. Of the 22 candidate vaccine peptides, 16 (n = 10 T cell epitope optimized; n = 6 B cell epitope optimized) were manually selected to decrease their degree of sequence overlap and then synthesized. The immunogenicity of the synthesized vaccine peptides was validated using ELISpot and ELISA following murine vaccination. Strong T cell responses were observed in 7/10 T cell epitope optimized peptides following vaccination. Humoral responses were deficient, likely due to the unrestricted conformational space inhabited by linear vaccine peptides. Conclusions Overall, we find our selection process and vaccine formulation to be appropriate for identifying T cell epitopes and eliciting T cell responses against those epitopes. Further studies are needed to optimize prediction and induction of B cell responses, as well as study the protective capacity of predicted T and B cell epitopes.

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