Antigenic shift

Antigenic shift refers to the exchange of genetic information between different virus types or subtypes. For this, the virus must have a segmented genome, so that individual segments can be switched between the viruses within the same cell during the reproduction; the genetic process itself is called reassortment or reassortment.

The term antigenic shift is especially known influenza viruses as a result of antigenic shift leads to the appearance of new pathogenic variants and is responsible for the outbreak of a global pandemic. In contrast to the antigenic drift an entire gene segment is replaced here just. Thus, new subtypes with new combinations of surface antigens (for example, haemagglutinin and neuraminidase in influenza A/H5N1 ). Condition for an antigenic shift is the simultaneous infection of a host cell (for example, in the common host pork or duck) by different virus strains. It is suspected that the antigenic shift a targeted viral mechanism is based on the antigenic shift so does not happen by accident.