DISINTEGRATION 07'' VIRUSES 



41 



is happening. It is merely a familiar trick of the physical chemist to dodge 

 an embarrassing issue. 



Influenza Virus 



In the remainder of this chapter the Inactlvation or denaturation of in- 

 fluenza virus will be discussed. Influenza virus has three Interesting bio- 

 logical activities, ju'irst and foremost is the ability of the virus to Infect 

 animals, Including man, the mouse, and the chicken embryo. Another interesting 

 property of influenza virus is its ability to agglutinate red blood cells of 

 chickens and of certain other animals. Xhis ability was first discovered by 

 Hirst of the Rockefeller foundation, it constitutes an extremely useful property 

 of the virus. A third biological activity of Influenza virus is the ability to 

 induce specific protecting antibodies in the blood stream of hosts which have 

 been inoculated with the virus or which have been subjected to influenza infect- 

 ions. All of these biological properties seem to be associated with the 100- 

 millimicron spherical particles now accepted as the Influenza virus. 



The ability to agglutinate red cells can be measured quantitatively with 

 a probable error of something like 10 to 2^%, This is done by finding the con- 

 centration of virus necessary to agglutinate half of the red cells in a 3/"* or 

 1% suspension. Since the agglutination ability can be estimated more or less 

 quantitatively, its rate of destruction can be measured more or less quantita- 

 tively. The rate of destruction of the ability to agglutinate red blood cells 

 has been studied under a variety of conditions. As can be seen in yigure 33» 

 when a solution of Influenza A virus is heated, the reciprocal of the square 

 root of red blood cell agglutinating activity is a linear function of time. 



-\^ 



FIGURE 33 - RECIPROCAL OF SQUARE ROOT OF HEJiAGGLUTININ 

 ACTIVITY OF PR 8 INFLUENZA A VIRUS PLOTTED A5? A FUNCTION 

 OF HEATING AT 6l° C. IN PHOSPHATE BUFFER AT pH 6.9 (M.A. 

 Lauffer and H.L. Carnelly, Arch Biochem. 8, 265 (194?; ;. 



This means that the ability to agglutinate is destroyed by heating and that the 

 relationship of the amount remaining to time is the one shown. This is an un- 

 expected complication. One would anticipate that the destruction of hemag- 

 glutinin would be a reaction of the first order. Instead, the data shown in 

 this figure indicate that the reaction is of the three halves order. In all 

 probability this apparent order is not real, for a complicated kinetic picture 

 such as this could result from inhomogeneity of the agglutinating factor with 

 respect to rate of destruction. In any case, the linear relationship between 

 the reciprocal of the square root of concentration and the time affords a con- 

 venient empirical method of determining the relative rates of the reaction under 



