CJD is one of the Transmissible Spongiform Encephalopathy (TSE) that affect man (human, homo sapien), the others are Kuru, Gerstmann Straussler Scheinker syndrome (GSS) and Fatal Familial Insomnia (FFI).
Other examples of TSEs are Bovine Spongiform Encephalopathies (BSE, mad cow disease, cattle), Scrapie (sheep, goats), Chronic Wasting Disease (CWD, CWDD, mule deer, white-tailed deer, black-tailed deer, elk), Feline Spongiform Encephalopathy (FSE, cats), Transmissible Mink Encephalopathy (TME, mink), Transmissible Spongiform Encephalopathy of Captive Wild Ruminants ( eland, Arabian oryx, greater kudu, gemsbok, nyala, scimitar horned oryx, ankole, bison).
Summary of Prion Diseases and transmission
| Disease | Host | Mechanism of Pathogenesis |
|---|---|---|
| Kuru | Human beings | Infection through ritualistic cannibalism |
| Gerstmann Straussler Scheinker syndrome(GSS) | Human beings | Germ-line mutations in PrP gene |
| Fatal Familial Insomnia (FFI) | Human beings | Germ-line mutations in PrP gene |
| Sporadic Familial Insomnia (SFI) | Human beings | Spontaneous conversion of PrPC to PrPSc |
| Iatrogenic CJD (iCJD) | Human beings | Infection from prion-contaminated human growth Hormone (hGH),dura mater grafts etc |
| Variant CJD (vCJD) | Human beings | Infection from bovine prions |
| Familial CJD (fCJD) | Human beings | Germ-line mutations in PrP gene |
| Sporadic CJD (sCJD) | Human beings | Somatic mutations, or spontaneous conversion of PrPC to PrPSc |
| Scrapie | Sheep, Goats | Infection in genetically susceptible sheep |
| Bovine Spongiform Encephalopathy (BSE) | Cattle | Infection with prions from sheep or cattle |
| Transmissible Mink Encephalopathy (TME) | Mink | Infection with prions from sheep or cattle |
| Chronic wasting disease | Mule deer, White-tailed deer, Black-tailed deer, Elk | Unknown |
| Feline spongiform encephalopathy | Cats | Infection with prion-contaminated bovine tissues or meat and bone meal |
| Exotic ungulate encephalopathy | Eland, Arabian oryx, Greater kudu, Gemsbok, Nyala, Scimitar horned oryx, Ankole, Bison | Infection with prion-contaminated meat and bone meal |
TSEs are degenerative disorders of the central nervous system (CNS) and brain that lead to motor dysfunction, dementia, and death.
The exact mechanisms for transmission are yet unknown, however normal prion protein, PrP or PrPc (a ubiquitously expressed protein) undergoes conversion to an abnormal prion protein termed PrPsc. The sc designation means scrapie but other labels such as cjd, and res have been used to describe the abnormal form.
PrPsc accumulates in the brain and amyloid like aggregates are visible upon histological analysis. These aggregates are associated with the appearance of large patterns of vacuolation. The vacuolation indicates neuronal cell death and the pattern makes the tissue resemble a sponge like appearance.
The samples we have available are human brain and spleen homogenates from sporadic CJD (sCJD, spCJD) sources, new variant CJD (vCJD, nvCJD) sources and control (clinically non-CJD, normal, ctrl) sources and 16-20 amino acid long peptides (synthesised fragments of the prion protein). We also have available limited quantities of sheep (ovine) scrapie and cow (bovine) BSE brain, spleen, blood and blood components. We are also in the process of developing other resources (and making available reference materials) to facilitate research into this area.
These brain samples and spleen samples have been characterised (so far) by Immunoblot (Western Blotting), ELISA, DNA sequencing, Protein Assay and STR. Other diagnostic and characterisation tests are currently undergoing investigation.
Some of the brain samples are now classed as CJD brain reference standards by the WHO (World Health Organisation) after collaborative studies. Other samples are due to or are currently undergoing collaborative study evaluation.