Projects / Programmes
A study of the cellular immune response to peptides from prion protein
| Code |
Science |
Field |
Subfield |
| 3.01.00 |
Medical sciences |
Microbiology and immunology |
|
| Code |
Science |
Field |
| B000 |
Biomedical sciences |
|
| B500 |
Biomedical sciences |
Immunology, serology, transplantation |
Prion diseases, peptides, in vitro assays, T lymphocytes, activation and proliferation, cytokine activation, specific cell marker expression.
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
28281 |
PhD Mascia Ghielmetti |
Microbiology and immunology |
Head |
2007 - 2008 |
6 |
Organisations (1)
Abstract
Prion diseases, including Bovine Spongiform Encephalopathy (BSE), Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS) and Fatal Familial Insomnia (FFI) are fatal and neurodegenerative infectious disorders in animals and humans, respectively. Normal cellular prion protein (PrPC) is expressed on the surface of various cell types, but most abundantly on neurons. Posttranslational conversion of PrPC into a pathological scrapie prion protein (PrPSc) leads to extensive neuronal cell loss by a yet unclear mechanism. Irreversible brain damage is reflected as loss of coordination and dementia.
Since prion diseases are transmissible within and even between species, the need for pre- and post-exposure treatment is evident. In fact, BSE has been transmitted from cattle to humans to cause a new variant of Creutzfeldt-Jakob disease (vCJD). In recent years, transmission by blood transfusion was reported.
So far, prion diseases are best investigated in the mouse model. In prion-infected mice, the abnormal proteins can be detected on cells in the spleen and lymph nodes before they reach the brain. Surprisingly, PrPSc infection of the host does not induce an antibody (Ab) response, indicating immune tolerance due to the similarity with the normal PrPC. Since the pathologic effect is limited to the brain, the effective treatment in early prion infection is needed. To overcome a long incubation period, in vitro assays are required to investigate the effect of PrP on cells of the human immune system.
In the recent years, the research group Biomedicine in the Centre for the Production of Diagnostic Reagents and Research, Blood Transfusion Center of Slovenia, Ljubljana, was able to improve the knowledge and techniques in the basic prion research, having also applicative value. In particular, a sensitive assay was developed to detect the pathological PrPSc isoform by generating a monoclonal Ab, specific for human prion protein that discriminates between CJD – affected and normal brain tissue1,2,3. Furthermore, the laboratory developed a fast technology, based on the Real Time PCR, to analyze genetic risk factors, associated with CJD in Slovenians4.
To continue prion research, the main goal of the present project is to assess the capacity of different synthetic peptides, based on the human PrP sequence, which were already used to stimulate B lymphocytes in vivo1,2, to activate T lymphocytes in vitro. The methods will be established first in in vitro assays on isolated mouse and later also on human T lymphocytes. In particular, we will focus on T cell proliferation, cytokine production and specific cell marker expression. The results will provide the amino acid sequence required for lymphocyte activation. Since it is known that the pathogenic prion protein forms aggregates, we will investigate the activation capacity of different conformations, including dimers and polymers of the most effective peptide, P11,2,5. In a final step, we will establish a system to predict the stimulatory potency of prion peptides on human T cells in vitro.
Our investigations will support the generation of a specific prion treatment, particularly a vaccine formulation appropriate also for human use.
1Čurin Šerbec V, Bresjanac M, Popović M, Pretnar Hartman K, Galvani V, Rupreht R, Černilec M, Vranac T, Hafner I, Jerala R., J Biol Chem, 2004; 279: 3694-3698.
2Vranac T, Hartman KP, Popović M, Venturini A, Zerovnik E, Čurin Šerbec V. Peptides. 2006 Jul 19; [Epub ahead of print]
3 Čurin Šerbec, V. Antibodies capable to selectively detect prion PrPSc isoforms. EP 1158003, 2005.
4Galvani V., Rupreht RR, Čurin Šerbec V, Vidan-Jeras, B, Transfus Med, 2005; 15: 197-207.
5Poklar Ulrih N, Skrt M, VeraniČ P, Galvani V, Vranac T, Čurin Šerbec V, BBRC, 2006 ; 344 : 1320-1326.
Significance for science
To date, no efficeint treatment for prion diseases are available. Here we focused on the cellular immune system. The main problem is the similarity between PrPC and PrPSc. In the past years our group studied specific antibody responses to chosen peptides from the human prion protein sequence.
To improve our understanding of immune tolerance and the immunogenicity of prion peptides we expanded our investigations to cellular immune responses. To this aim we set up two models, a human and a mouse model, which are very useful for the detection of autoimmune side effects of particulate peptides.
With the help of a human in vitro model we could optimize the mouse model. From the blood of healthy blood donors we got enough cells to investigate different conditions, which were then adapted accordingly in the mouse model.
In the mouse model it is possible to study the whole immune response to a peptide; i.e. T-cell response and specific antibodies. With this, we can better understand the immune response to a selected prion peptide as such.
These results are and will be important for the understanding of immunity in prion diseases and the possible vaccine development.
Significance for the country
In the last years, the reasearch group Biomedicine was able to improve basic prion research. With this project we succeeded in expanding our knowledge and techniques in the filed of immunology and therefore also in prion diseases. This will be helpful for the development of other projects and the setup of new ideas. Further, the investigations will support the generation of a specific prion treatment.
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