Antigenic drift

The two vaccines currently available for prevention of influenza are the trivalent influenza vaccine (TIV) and the live-attenuated influenza vaccine (LAIV). The specific strains included in the vaccine each year change based on antigenic drift. 

Some of the reasons for the return are as follows (i) new breeding grounds for the insects that are vectors for some pathogens (ii) antigenic drift in viruses and bacteria (iii) resistance to antibiotics (iv) a decrease in the effectiveness of the immune system due to the presence of other more chronic infections, poor nutrition or stress (v) expansion of air travel. 

Some additional subunit vaccines are being developed, based upon internal viral polypeptides, particularly the p24 core protein. This was chosen as it is known to contain epitopes capable of eliciting a T cell response, and core proteins are generally less subject to antigenic drift than envelope proteins. 

Both GW, Sleigh MJ, Cox NJ, Kendal AP. Antigenic drift in influenza virus H3 haemagglutinin from 1968 to 1980 multiple evolutionary pathways and sequential amino acid changes at key antigenic sites. J Virol 1983 48 52-60. 

Donnelly JJ, Friedman A, Martinez D, Montgomery DL, Shiver JW, Motzel SL, Ulmer JB, Liu MA. Preclinical efficacy of a prototype DNA vaccine enhanced protection against antigenic drift in influenza virus. Nature Med 1995 1 583-586. 

In specific reference to the expression of melanocytic markers in metastatic tumors, Plaza and colleagues °° have demonstrated that there is little if any antigenic drift as compared with primary melanoma. 

There is an inherent disadvantage when using highly specific antibodies. Antigenic drift or shift can make using monoclonal antibodies difficult. The evolution... 

Antigenic drift Process of antigenic variation that results from mutations in genes coding for hemagglutinin and neuramin-dase. 

Antigenic variation Mutations of influenza viruses that occur by antigenic drift and antigenic shift. 

Viruses often present a special class of mutants called escape mutants. The mutation(s) occurs at neutralizing immunogenic sites such that the alteration of antigenicity allows the virus to escape from the neutralizing antibodies of the host. Influenza viruses are notorious for their propensity to undergo such mutations, which are specifically called antigenic drift. 

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