Which or tile following is true about antigenic drift?
(A) It is seen only in influenza virus type A (B) It is a result of framesshift mutation (C) It mostly affects the matrix protein (D) It mostly affects the matrix protein
(D) Ans: D. It mostly affects the matrix protein(Ref: Park 24/e p164, 23/e p154, 22/e p145)Antigenic drift:Mechanism for variation in viruses that involves the accumulation of mutations within genes that code for antibody binding sites.Results from genetic recombination of human with animal or an virus, providing a major antigenic change.This can cause a major epidemic or pandemic involving most or all age groups.Antigenic drift involves point mutation in the genes owing to selection pressure by immunity in the host population.This results in a new strain of virus paicles, which cannot be inhibited as effectively by the antibodies that were originally targeted against previous strains, making it easier for the virus to spread throughout a paially immune population, responsible for seasonal epidemics of influenza.