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Viral infections and innate immunity (Master thesis)

Ευθυμίου, Γεώργιος/ Efthymiou, Georgios/ Λοιμώδη Νοσήματα - Διεθνής Ιατρική: από το Εργαστήριο στην Κλινική Πράξη

Respiratory Syncytial Virus (RSV) remains a major health concern, since it constitutes the leading cause of hospitalization among infants in developed countries and second most frequent reason of lower respiratory mortality globally. Neutrophils play a significant role in the host innate immune response and serve as the body’s first line of defense against infection. One of the three strategies they utilize in the elimination of invading microbes is the release of Neutrophil Extracellular Traps (NETs) which are composed of decondensed chromatin, decorated with antimicrobial proteins. Previous studies have shown that the human cathelicidin LL-37, in its active form, is expressed on NETs, and is also responsible for NETs’ antimicrobial activity. Clinical samples (serum and nasopharyngeal) from positive for RSV patients were collected and their ability to induce NETs were evaluated. Moreover, the expression of LL-37, as well as the levels of LL-37 mRNA were analyzed. RSV positive patients had higher LL-37 levels, on NETs when neutrophils were activated with nasopharyngeal samples, while LL37’s expression after activation with the serum showed no significant increase. The above indicates that the antimicrobial peptide accumulates and acts on the site of the RSV infection.