Promiscuous T-cell epitopes of Plasmodium merozoite surface protein 9 (PvMSP9) induces IFN-γ and IL-4 responses in individuals naturally exposed to malaria in the Brazilian Amazon

ABSTRACT Cross-sectional seroepidemiological studies of populations naturally exposed to Plasmodium falciparum suggest an association between protection from malaria and circulating antibodies to the carboxyl terminus of merozoite surface protein 1 (MSP1). Questions remain regarding the significance of cell-mediated immunity to MSP1 in conferring protection and inducing immunologic memory. Vaccine constructs have been based on the 42-kDa recombinant MSP1 protein (MSP142), which includes the 19-kDa (MSP119) and 33-kDa (MSP133) fragments containing the major B- and T-cell epitopes, respectively. To evaluate T-cell responses to the MSP133 fragment, two libraries of overlapping 18-mer peptides from the 3D7 and FVO MSP133 regions were used to screen a cohort of asymptomatic Kenyan adults. Gamma interferon (IFN-γ) measured by enzyme-linked immunospot assay (ELISPOT) at multiple time points assessed the magnitude and stability of these responses. The percentage of individuals with IFN-γ responses to single MSP133 peptides ranged from nil to 24%, were clustered among a subset of peptides, and were not consistently recalled over time. In comparison to peptide responses, IFN-γ ELISPOT responses to recombinant MSP142 were more prevalent, more frequently elicited by the 3D7 as opposed to the FVO allele, and more stable over time. The prevailing MSP133 genotype infection was 3D7, with few mixed infections and no sole FVO infections. This study demonstrates that immunity against MSP133 after cumulative natural infections consists of low-magnitude and difficult-to-detect IFN-γ responses. Although immunity against MSP1 alone will not confer protection against malaria, demonstrating a relative and sustained increase in T-cell immunity to MSP1 after vaccination would be a reasonable measurement of vaccine responsiveness.

Download Full-text

Evaluation of the Immunogenicity and Vaccine Potential of Recombinant Plasmodium falciparum Merozoite Surface Protein 8

Infection and Immunity ◽

10.1128/iai.00211-12 ◽

2012 ◽

Vol 80 (7) ◽

pp. 2473-2484 ◽

Cited By ~ 11

Author(s):

James R. Alaro ◽

Evelina Angov ◽

Ana M. Lopez ◽

Hong Zhou ◽

Carole A. Long ◽

...

Keyword(s):

Plasmodium Falciparum ◽

T Cell ◽

Surface Protein ◽

Merozoite Surface Protein ◽

Plasmodium Yoelii ◽

Full Length ◽

T Cell Epitopes ◽

Content Type ◽

Rich Domain ◽

Vaccine Potential

ABSTRACTThe C-terminal 19-kDa domain of merozoite surface protein 1 (MSP119) is the target of protective antibodies but alone is poorly immunogenic. Previously, using thePlasmodium yoeliimurine model, we fusedP. yoeliiMSP119(PyMSP119) with full-lengthP. yoeliimerozoite surface protein 8 (MSP8). Upon immunization, the MSP8-restricted T cell response provided help for the production of high and sustained levels of protectivePyMSP119- andPyMSP8-specific antibodies. Here, we assessed the vaccine potential of MSP8 of the human malaria parasite,Plasmodium falciparum. Distinct fromPyMSP8,P. falciparumMSP8 (PfMSP8) contains an N-terminal asparagine and aspartic acid (Asn/Asp)-rich domain whose function is unknown. Comparative analysis of recombinant full-lengthPfMSP8 and a truncated version devoid of the Asn/Asp-rich domain,PfMSP8(ΔAsn/Asp), showed that both proteins were immunogenic for T cells and B cells. All T cell epitopes utilized mapped within rPfMSP8(ΔAsn/Asp). The dominant B cell epitopes were conformational and common to both rPfMSP8 and rPfMSP8(ΔAsn/Asp). Analysis of nativePfMSP8 expression revealed thatPfMSP8 is present intracellularly in late schizonts and merozoites. Following invasion,PfMSP8 is found distributed on the surface of ring- and trophozoite-stage parasites. Consistent with a low and/or transient expression ofPfMSP8 on the surface of merozoites,PfMSP8-specific rabbit IgG did not inhibit thein vitrogrowth ofP. falciparumblood-stage parasites. These studies suggest that the further development ofPfMSP8 as a malaria vaccine component should focus on the use ofPfMSP8(ΔAsn/Asp) and its conserved, immunogenic T cell epitopes as a fusion partner for protective domains of poor immunogens, includingPfMSP119.

Download Full-text

Identification of frequently recognized dimorphic T-cell epitopes in plasmodium falciparum merozoite surface protein-1 in West and East Africans: lack of correlation of immune recognition and allelic prevalence.

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.2001.64.194 ◽

2001 ◽

Vol 64 (3) ◽

pp. 194-203 ◽

Cited By ~ 19

Author(s):

E A Lee ◽

A V Hill ◽

W H Reece ◽

K Odhiambo ◽

M Pinder ◽

...

Keyword(s):

Plasmodium Falciparum ◽

T Cell ◽

Surface Protein ◽

Merozoite Surface Protein ◽

Immune Recognition ◽

T Cell Epitopes ◽

Merozoite Surface Protein 1 ◽

Falciparum Merozoite

Download Full-text

Anaplasma marginale Major Surface Protein 2 CD4+-T-Cell Epitopes Are Evenly Distributed in Conserved and Hypervariable Regions (HVR), Whereas Linear B-Cell Epitopes Are Predominantly Located in the HVR

Infection and Immunity ◽

10.1128/iai.72.12.7360-7366.2004 ◽

2004 ◽

Vol 72 (12) ◽

pp. 7360-7366 ◽

Cited By ~ 35

Author(s):

Jeffrey R. Abbott ◽

Guy H. Palmer ◽

Chris J. Howard ◽

Jayne C. Hope ◽

Wendy C. Brown

Keyword(s):

T Cell ◽

B Cell ◽

Surface Protein ◽

Anaplasma Marginale ◽

T Cell Epitopes ◽

B Cell Epitopes ◽

Major Surface Protein ◽

Hypervariable Regions ◽

Major Surface ◽

Linear B

ABSTRACT Organisms in the genus Anaplasma express an immunodominant major surface protein 2 (MSP2), composed of a central hypervariable region (HVR) flanked by highly conserved regions. Throughout Anaplasma marginale infection, recombination results in the sequential appearance of novel MSP2 variants and subsequent control of rickettsemia by the immune response, leading to persistent infection. To determine whether immune evasion and selection for variant organisms is associated with a predominant response against HVR epitopes, T-cell and linear B-cell epitopes were localized by measuring peripheral blood gamma interferon-secreting cells, proliferation, and antibody binding to 27 overlapping peptides spanning MSP2 in 16 cattle. Similar numbers of MSP2-specific CD4+ T-cell epitopes eliciting responses of similar magnitude were found in conserved and hypervariable regions. T-cell epitope clusters recognized by the majority of animals were identified in the HVR (amino acids [aa] 171 to 229) and conserved regions (aa 101 to 170 and 272 to 361). In contrast, linear B-cell epitopes were concentrated in the HVR, residing within hydrophilic sequences. The pattern of recognition of epitope clusters by T cells and of HVR epitopes by B cells is consistent with the influence of protein structure on epitope recognition.

Download Full-text

Protective Vaccine Efficacy of the Complete Form of PPE39 Protein from Mycobacterium tuberculosis Beijing/K Strain in Mice

Clinical and Vaccine Immunology ◽

10.1128/cvi.00219-17 ◽

2017 ◽

Vol 24 (11) ◽

Cited By ~ 4

Author(s):

Ahreum Kim ◽

Yun-Gyoung Hur ◽

Sunwha Gu ◽

Sang-Nae Cho

Keyword(s):

T Cells ◽

Mycobacterium Tuberculosis ◽

T Cell ◽

Vaccine Development ◽

Protective Efficacy ◽

Interleukin 2 ◽

T Cell Epitopes ◽

Content Type ◽

Complete Form ◽

Ifn Γ

ABSTRACT The aim of this study was to evaluate the protective efficacy of MTBK_24820, a complete form of PPE39 protein derived from a predominant Beijing/K strain of Mycobacterium tuberculosis in South Korea. Mice were immunized with MTKB_24820, M. bovis Bacilli Calmette-Guérin (BCG), or adjuvant prior to a high-dosed Beijing/K strain aerosol infection. After 4 and 9 weeks, bacterial loads were determined and histopathologic and immunologic features in the lungs and spleens of the M. tuberculosis-infected mice were analyzed. Putative immunogenic T-cell epitopes were examined using synthetic overlapping peptides. Successful immunization of MTBK_24820 in mice was confirmed by increased IgG responses (P < 0.05) and recalled gamma interferon (IFN-γ), interleukin-2 (IL-2), IL-6, and IL-17 responses (P < 0.05 or P < 0.01) to MTBK_24820. After challenge with the Beijing/K strain, an approximately 0.5 to 1.0 log10 reduction in CFU in lungs and fewer lung inflammation lesions were observed in MTBK_24820-immunized mice compared to those for control mice. Moreover, MTBK_24820 immunization elicited significantly higher numbers of CD4+ T cells producing protective cytokines, such as IFN-γ and IL-17, in lungs and spleens (P < 0.01) and CD4+ multifunctional T cells producing IFN-γ, tumor necrosis factor alpha (TNF-α), and/or IL-17 (P < 0.01) than in control mice, suggesting protection comparable to that of BCG against the hypervirulent Beijing/K strain. The dominant immunogenic T-cell epitopes that induced IFN-γ production were at the N terminus (amino acids 85 to 102 and 217 to 234). Its vaccine potential, along with protective immune responses in vivo, may be informative for vaccine development, particularly in regions where the M. tuberculosis Beijing/K-strain is frequently isolated from TB patients.

Download Full-text

Plasmodium falciparumMSP3 Exists in a Complex on the Merozoite Surface and Generates Antibody Response during Natural Infection

Infection and Immunity ◽

10.1128/iai.00067-18 ◽

2018 ◽

Vol 86 (8) ◽

Cited By ~ 2

Author(s):

Arunaditya Deshmukh ◽

Bishwanath Kumar Chourasia ◽

Sonali Mehrotra ◽

Ikhlaq Hussain Kana ◽

Gourab Paul ◽

...

Keyword(s):

Malaria Vaccine ◽

Transmembrane Domain ◽

Natural Infection ◽

Surface Protein ◽

Merozoite Surface Protein ◽

Mass Spectrometry Analysis ◽

Enzyme Linked Immunosorbent Assay ◽

T Cell Epitopes ◽

Hyperimmune Serum ◽

Content Type

ABSTRACTPlasmodium falciparummerozoite surface protein 3 (MSP3) is an abundantly expressed secreted merozoite surface protein and a leading malaria vaccine candidate antigen. However, it is unclear how MSP3 is retained on the surface of merozoites without a glycosylphosphatidylinositol (GPI) anchor or a transmembrane domain. In the present study, we identified an MSP3-associated network on thePlasmodiummerozoite surface by immunoprecipitation ofPlasmodiummerozoite lysate using antibody to the N terminus of MSP3 (anti-MSP3N) followed by mass spectrometry analysis. The results suggested the association of MSP3 with other merozoite surface proteins: MSP1, MSP6, MSP7, RAP2, and SERA5. Protein-protein interaction studies by enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) analysis showed that MSP3 complex consists of MSP1, MSP6, and MSP7 proteins. Immunological characterization of MSP3 revealed that MSP3N is strongly recognized by hyperimmune serum from African and Asian populations. Furthermore, we demonstrate that human antibodies, affinity purified against recombinant MSP3N (rMSP3N), promote opsonic phagocytosis of merozoites in cooperation with monocytes. At nonphysiological concentrations, anti-MSP3N antibodies inhibited the growth ofP. falciparum in vitro. Together, the data suggest that MSP3 and especially its N-terminal region containing known B/T cell epitopes are targets of naturally acquired immunity against malaria and also comprise an important candidate for a multisubunit malaria vaccine.

Download Full-text

Identification of Rotavirus VP6-Specific CD4+ T Cell Epitopes in a G1P[8] Human Rotavirus-Infected Rhesus Macaque

Virology Research and Treatment ◽

10.4137/vrt.s563 ◽

2008 ◽

Vol 1 ◽

pp. VRT.S563 ◽

Cited By ~ 1

Author(s):

Wei Zhao ◽

Bapi Pahar ◽

Karol Sestak

Keyword(s):

T Cell ◽

Rhesus Macaques ◽

Immunoglobulin A ◽

Cd4 T Cell ◽

T Cell Epitopes ◽

Primate Model ◽

Human Rotavirus ◽

Ifn Γ ◽

Rotavirus Vp6

A non-human primate model was used to evaluate its potential for identification of rotavirus viral protein 6 (VP6) CD4+ T cell epitopes. Four juvenile rhesus macaques were inoculated with a mixed inoculum (G1P[8] and G9P[8]) of human rotaviruses. Infection accompanied by G1P[8] shedding was achieved in the two macaques that had no rotavirus immunoglobulin A (IgA) in plasma. To measure the interferon gamma (IFN-γ) and tumor necrosis factor (TNF) anti-viral cytokines produced by peripheral CD4+ cells that recognize VP6 epitopes, whole blood cells from one infected macaque were stimulated in vitro with VP6 peptides. Stimulation with peptide pools derived from the simian rotavirus VP6161–395 region revealed reactivity of CD4+ T cells with the VP6281–331 domain. A VP6301–315 region was identified as the epitope responsible for IFN-γ production while a broader VP6293–327 domain was linked to TNF production. These results suggest that human rotavirus-infected macaques can be used for identification of additional epitopes and domains to address specific questions related to the development of pediatric vaccines.

Download Full-text

T-Cell Epitopes in Severe Acute Respiratory Syndrome (SARS) Coronavirus Spike Protein Elicit a Specific T-Cell Immune Response in Patients Who Recover from SARS

Journal of Virology ◽

10.1128/jvi.78.11.5612-5618.2004 ◽

2004 ◽

Vol 78 (11) ◽

pp. 5612-5618 ◽

Cited By ~ 76

Author(s):

Yue-Dan Wang ◽

Wan-Yee Fion Sin ◽

Guo-Bing Xu ◽

Huang-Hua Yang ◽

Tin-yau Wong ◽

...

Keyword(s):

T Cell ◽

Cell Epitope ◽

T Cell Response ◽

Cell Immune Response ◽

T Cell Epitopes ◽

Online Database ◽

Database Analysis ◽

S Protein ◽

Healthy Donors ◽

Ifn Γ

ABSTRACT The immunogenicity of HLA-A2-restricted T-cell epitopes in the S protein of the Severe acute respiratory syndrome coronavirus (SARS-CoV) and of human coronavirus strain 229e (HCoV-229e) was analyzed for the elicitation of a T-cell immune response in donors who had fully recovered from SARS-CoV infection. We employed online database analysis to compare the differences in the amino acid sequences of the homologous T epitopes of HCoV-229e and SARS-CoV. The identified T-cell epitope peptides were synthesized, and their binding affinities for HLA-A2 were validated and compared in the T2 cell system. The immunogenicity of all these peptides was assessed by using T cells obtained from donors who had fully recovered from SARS-CoV infection and from healthy donors with no history of SARS-CoV infection. HLA-A2 typing by indirect immunofluorescent antibody staining showed that 51.6% of SARS-CoV-infected patients were HLA-A2 positive. Online database analysis and the T2 cell binding test disclosed that the number of HLA-A2-restricted immunogenic epitopes of the S protein of SARS-CoV was decreased or even lost in comparison with the homologous sequences of the S protein of HCoV-229e. Among the peptides used in the study, the affinity of peptides from HCoV-229e (H77 and H881) and peptides from SARS-CoV (S978 and S1203) for binding to HLA-A2 was higher than that of other sequences. The gamma interferon (IFN-γ) release Elispot assay revealed that only SARS-CoV-specific peptides S1203 and S978 induced a high frequency of IFN-γ-secreting T-cell response in HLA-A2+ donors who had fully recovered from SARS-CoV infection; such a T-cell epitope-specific response was not observed in HLA-A2+ healthy donors or in HLA-A2− donors who had been infected with SARS-CoV after full recovery. Thus, T-cell epitopes S1203 and S978 are immunogenic and elicit an overt specific T-cell response in HLA-A2+ SARS-CoV-infected patients.

Download Full-text

Thyrotropin-Receptor and Thyroid Peroxidase-Specific T Cell Clones and Their Cytokine Profile in Autoimmune Thyroid Disease1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.82.11.4336 ◽

1997 ◽

Vol 82 (11) ◽

pp. 3655-3663

Author(s):

Maria Elena Fisfalen ◽

Ellen M. Palmer ◽

Gijs A. van Seventer ◽

Keyoumars Soltani ◽

Yoshikuni Sawai ◽

...

Keyword(s):

Amino Acid ◽

T Cell ◽

Thyroid Tissue ◽

Cytokine Profile ◽

Thyroid Peroxidase ◽

Amino Acid Residues ◽

T Cell Epitopes ◽

T Cell Clones ◽

Cell Clones ◽

Ifn Γ

We studied the cytokine profile and the immune responses to thyroid antigens of specific T cell clones (TCC) isolated from patients with Hashimoto’s thyroiditis (HT) and Graves’ disease (GD). Antigen-specific TCC were reactive to thyroid peroxidase (TPO), thyroglobulin (Tg) or human recombinant TSH-receptor extracellular domain (TSH-R), and/or their respective peptides. Of the 43 clones derived from HT patients, 65% were reactive to TPO, and 59% of the 32 clones derived from GD patients were reactive to TSH-R. TPO epitopes 100–119 and 625–644 were recognized by 75% of HT-derived clones, whereas TSH-R epitopes 158–176, 207–222, and 343–362/357–376 were recognized by 85% of GD-derived TCC. The TCC were classified according to their cytokine profile into T helper cell (Th)0 [secreting interleukin (IL)-4, IL-5, interferon (IFN)-γ], Th1 (secreting IFN-γ) and Th2 (secreting IL-4 and/or IL-5). Tumor necrosis factor-β and IL-10 were produced by all subsets. The specific TCC were predominantly Th1-like cells in HT, and were Th0- and Th1-like cells in GD. Fifty three percent of Th0 clones were derived from GD patients and were reactive to TSH-R, whereas 50% of Th1 clones were derived from HT patients and were reactive to TPO or Tg. Most Th2 clones (82%) were reactive to TPO and were established from peripheral blood. All these clones produced IL-5, and 64% produced IL-4 and IL-10. Interestingly, IFN-γ was highly produced by TPO- or Tg-specific clones established from HT thyroid tissue. These results confirm at the clonal level our previous studies regarding T cell epitopes on TPO and TSH-R molecules and support the concept that immunodominant T cell epitopes are located on amino acid residues 100–119 and 625–644 of TPO in HT and amino acid residues 158–176, 207–222 and 343–362/357–376 of TSH-R in GD. Our studies also demonstrate that thyroid-specific T cells can be classified into Th0, Th1, and Th2 subsets. TPO- or Tg-specific clones with Th1 phenotype appear to be involved in the pathogenesis of HT, mediating thyroid tissue destruction, whereas TSH-R clones with Th0 phenotype may induce thyroid-stimulating autoantibodies in GD.

Download Full-text