3.'iO Mirroorgaiiisms (chap. 20) 



results: 



Negri bodies — deep red 



comments: 



Massignani and Refinetti in their paper (1958) adapted the Papani- 

 colaou stain for Negri bodies. Further study, however, led to the 

 discovery that eosin combined ^vith phosphotiingstic acid is respon- 

 sible for Negri body staining and the above stain was developed 

 specifically for these bodies. 



Antigen-Antibodies 



The subject of immunity is complex and has filled several large text- 

 books. It is mentioned briefly here to bring to mind certain principles 

 used in this field, and to highlight one of the most important technics 

 developed for locating antigens and antibodies in tissues. 



If foreign materials, living or nonliving — bacteria and viruses, for 

 instance — invade the body, certain substances are formed in body fluids 

 to combat these foreis^n materials and "neutralize" them. The defense 

 substances are proteins called antibodies that have the po^ver to com- 

 bine specifically with the invading foreign materials (antigens) which 

 induced the formation of the antibodies. Eventual immunity to an 

 infection can be brought about either by entrance of the antigen natu- 

 rally or artificially — by "shots," for instance. In the latter case, serum, 

 called antiserum (immune serum) from an artificially immunized ani- 

 mal can be injected into a nonimmune animal to induce immunity. 

 Antiserum can be used in this way to combat an infection already 

 present (mumps, measles, anthrax, tetanus) or it can be used to prevent 

 infection (measles, poliomyelitis, tetanus, diphtheria). 



If the fluid portion of blood plasma is allowed to clot (fibrinogen 

 precipitates out) a relatively stable serum remains. This is made up of 

 two protein fractions: albumin and globulin. The globulins consist of 

 two alpha globulins, one beta globulin, and one gamma globulin. It is 

 the latter globulin which is associated with immiuiity. Antibodies have 

 been classically identified with gamma globulin (to a lesser extent with 

 the other globulins, also) and are considered modified serum globulin. 

 It has become a common practice to use for immime serum the gamma 

 globulin fraction, which can be isolated from the other serum proteins 

 and used in a concentrated form. The difference, therefore, between 

 immune and normal serum globulin lies in the ability of the former to 

 combine with an antigen. 



