The role of immune system in control of the influenza pandemic

Abstract

Virusi gripe su jednolončani RNA virusi koji pripadaju porodici Orthomyxoviridae. Postoje 3 tipa virusa: A, B i C, koji se razlikuju po virulenciji i genomskoj strukturi. Mutacijom gena dvaju površinskih proteina virusa influence, hemaglutinina i neuraminidaze, nastaju antigenske promjene na površini virusne čestice. Zahvaljujući tim promjenama, zaštitna uloga imunosustava može postati neadekvatna ako se virus influence izmijeni u tolikoj mjeri da sadrži antigene na koje osoba nema razvijenu niti humoralnu niti staničnu imunost. Težina kliničke slike u gripi ovisit će tada o sposobnosti virusa influence da zaobiđe ili inhibira različite imunološke mehanizme kojima je cilj eliminacija virusa iz organizma. Upravo sposobnost promjene antigenskih determinanti otežava razvoj cjepiva dovoljno sličnom epidemijskom odnosno pandemijskom soju virusa gripe. U ovom radu raspravit će se uloga imunološkog sustava u obrani organizma od virusa influence s posebnim osvrtom na dosadašnje spoznaje o imunološkoj reakciji u ljudi inficiranih mogućim pandemijskim virusom H5N1.Influenza virus is a single-stranded RNA virus of Orthomyxoviridae family. The 3 types of influenza virus, A, B and C, differ in virulence and genomic structure. Frequent mutations in viral surface glycoproteins, hemagglutinin and neuraminidase, result in the changes of antigenic determinants. As a consequence, protective role of immune system becomes inadequate if the changes of influenza virus are significant and accompanied with lack of existing humoral and cellular immunity in an infected individual. The severity of clinical presentation will depend on the capacity of influenza virus to evade or to inhibit different immunologic mechanism, which aim to eliminate the virus from the body. The frequent changes of influenza antigens also hamper the timely development of vaccine as a most important measure to protect from potential influenza epidemics or pandemics. In this paper we discuss the role of immune system in protection from influenza infection with special emphasis on the known findings of immune response in H5N1-infected individuals