Značaj prisutnosti CD4+ T limfocita specifičnih za SARS-CoV-2 u zdravih ljudi

master's thesis

• Title (english): Significance of presence of CD4+ T lymphocytes specific for SARS-CoV-2 in peripheral blood of helathy individuals
• Author: Matea Majta
• Mentor: Robert Likić (mentor)
• Committee member: Nadira Duraković (predsjednik povjerenstva)
• Committee member: Jasenka Markeljević (član povjerenstva)
• Committee member: Robert Likić (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; (Department of Internal Medicine); Zagreb
• Defense date and country: 2022-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences; Internal Medicine

Abstract

Pojavom pandemije SARS-CoV-2 znanost i čovječanstvo našli su se pred nizom novih izazova i prepreka. Od prvih karantena do razvoja cjepiva prošlo je nepunih godinu dana i medicina je napredovala nevjerojatnom brzinom. Pojavom novih varijanti virusa i rastom broja umrlih od COVID-19 znanstvenici su krenuli u detaljnu razradu imunosnog odgovora ljudskog organizma na infekciju SARS-CoV-2.
Od trenutka ulaska virusa u stanicu preko ACE2 receptora pokreću se mehanizmi urođenog imunosnog sustava te dolazi do aktivacije niza stanica kao što su neutrofili, makrofagi, dendritičke stanice, bazofili i eozinofili. Dolazi do lučenja velikih količina kemokina i citokina koji regrutiraju stanice imunosnog sustava na mjesto infekcije. Nakon samo 7 dana od infekcije dolazi do pojave protutijela usmjerenih protiv inficiranih stanica koja sprječavaju daljnji ulazak virusa u stanice domaćina vežući se za S protein. Paralelno s urođenim imunosnim sustavnom dolazi do aktivacije stanične imunosti te interakcija CD4+ i CD8+ T limfocita sa svrhom uništenja inficiranih stanica. Potom slijedi faza razrješenja bolesti i stvaranja stečenog imuniteta koji štiti od daljnjih reinfekcija. Dugo se mislilo da su za to zaslužna protutijela koja nastaju iz plazma stanica, ali danas se smatra da ta uloga pripada upravo CD4+ limfocitima T.
Ove stanice pokazale su križnu reaktivnost sa SARS-CoV-2 u neizloženih pojedinaca, a njihov odgovor na cijepljenje protiv SARS-CoV-2 daje vrlo burnu reakciju gdje dolazi do stvaranja velikih količina stanica koje u našem organizmu ostaju prisutne čak i do 9 mjeseci. Također se smatra da bi ove stanice mogle biti ključan odgovor na pitanje zašto je starija populacija susceptibilnija na infekciju SARS-CoV-2 te zašto imaju lošije ishode bolesti. Njihova uloga i značaj u dugotrajnoj imunosti protiv SARS-CoV-2 i drugih vrsta HCoV u zdravih pojedinaca do ovog trenutka nije u potpunosti poznata, ali je aktualna tema brojnih istraživanja.

Abstract (english)

With the emergence of the SARS-CoV-2 pandemic, science and humanity have been faced with several new challenges and obstacles. Less than a year passed from the first quarantines to the development of the vaccine, and medicine progressed at an incredible rate. With the emergence of new variants of the virus and the growing number of deaths from COVID-19, scientists have embarked on a detailed evaluation of the human body's immune response to the SARS-CoV-2 infection.
From the moment the virus enters the cell via ACE2 receptors, the mechanisms of the innate immune system are triggered and numerous cells such as neutrophils, macrophages, dendritic cells, basophils and eosinophils are activated. Large amounts of chemokines and cytokines are secreted that recruit immune system cells to the site of infection. Only 7 days after the infection, antibodies are directed against infected cells that prevent the virus from further entering the host cells by binding to the S protein. In parallel with the innate immune system, cellular immunity is activated and CD4 + and CD8 + T lymphocytes interact with the purpose of destroying infected cells. This is followed by a phase of resolving the disease and creating an acquired immunity that protects against further reinfections. It has long been thought that antibodies produced by the plasma cells are responsible for this, but today it is believed that this role belongs to CD4 + T lymphocytes.
These cells have shown cross-reactivity with SARS-CoV-2 in non-exposed individuals, and their response to vaccination against SARS-CoV-2 gives a very violent reaction where large amounts of cells are formed that remain present in our body for up to 9 months. It is also thought that these cells could be a key answer to the question of why the elderly population is more susceptible to SARS-CoV-2 infection and why they have poorer disease outcomes. Their role and importance in long-term immunity against SARS-CoV-2 and other types of HCoV in healthy individuals is not fully known to date but is a current topic of numerous studies.

• Keywords: SARS-CoV-2; COVID-19; CD4+ limfociti T; križna reaktivnost
• Keywords (english): SARS-CoV-2; COVID-19; CD4 + T lymphocytes; immunity
• Language: croatian
• URN:NBN: urn:nbn:hr:105:662727
• Study programme: Title: Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-01-17 12:44:12