Evaluating the Prevalence and Characteristics of Chlamydia pneumoniae, Its Structural Components and Infection-Induced Leukocyte-Derived Extracellular Vesicles in the Blood of Finnish Blood Donors

Project: Research project

Project Details

Description (abstract)

The microbiological quality of biopharmaceuticals is an important factor for assuring their safety and effectiveness and this also holds true for donated blood and blood products. They can contain a variety of infectious agents, of which only the most dangerous ones are included in the WHO screening recommendations on donated blood to prevent transfusion-transmitted infection. The small, Gram-negative and obligate intracellular bacterium Chlamydia pneumoniae is not one of them. C. pneumoniae infections affect primarily the respiratory tract and even though they often remain asymptomatic, complete bacterial eradication is, due to triggered as well as spontaneously occurring, antibiotic-refractory, yet incompletely understood persistence mechanisms, very difficult to impossible. C. pneumoniae's ability to survive phagocytosis by peripheral blood mononuclear cells contributes to its dissemination to extrapulmonary body sites where a causal relationship with the development of chronic inflammatory diseases, e.g., atherosclerosis and Alzheimer's disease, is suspected. We employ PCR methods and flow cytometry to detect C. pneumoniae DNA, RNA and antigens in the blood of Finnish blood donors and conduct viability and infectivity studies with positive samples. This may contribute to hemovigilance and the microbiological safety of blood products.
As a field of emerging quality assurance for blood products extracellular vesicles (EVs) are gaining more and more popularity. EVs are characterized based on their parental cell line, state and environmental conditions and play important roles in cell-cell communication and excretion of unwanted intracellular material. In disease they are linked to inflammation, immune response and thrombosis and seem to play an important role in tumor development. Leuko-, erythro- and thrombocyte-derived EVs are prone to emerge through the processing steps of donated blood alone, and at least the latter two show a direct proportional increase with advanced storage time and, therefore, cellular disintegration. About leukocyte-derived EVs little to nothing is known in regard to assessing blood quality except for the inability of leukoreduction processes to clear the blood products of them and their contribution to disease progression in e.g., pulmonary hypertension, diabetes and cardiovascular diseases. We use a nanoparticle tracker, PCR methods and flow cytometry to characterize leukocyte-derived and chlamydial infection-induced leukocyte-derived EVs. This will contribute to our understanding of chlamydial persistence and could pave the way for leukocyte-derived EVs being used as an emerging field for assuring the quality of blood products.
Effective start/end date01/05/202330/04/2027

Fields of Science

  • 317 Pharmacy
  • biopharmaceuticals
  • quality assurance
  • transfusion-transmitted infection
  • extracellular vesicles