32 LABORATORY COURSE IN SERUM STUDY 



1 or more outfits for bleeding guinea pigs : 



scissors, 

 forceps, 

 ether cone, 

 centrifuge tubes. 



MATERIALS 

 Each student will require : 



Washed sheep cells 5 % 6.0 c.c. 



Guinea pig serum 1-10 6.0 c.c. 



Inactive serum of rabbit immunized against 

 sheep cells, diluted so that each c.c. con- 

 tains 2-4 hsemolytic doses 6.0 c.c. 



LESSON IV 



QUANTITATIVE RELATIONSHIPS OF AMBOCEPTOR AND 



COMPLEMENT 



METHODS OF TITRATION 



THE haemolysis of red cells by specific sensitizer [or ambocep- 

 tor] and alexin [or complement] is a delicately quantitative 

 reaction in which very definite amounts of the three substances 

 are necessary to produce a complete reaction. As a unit of red 

 cells, one cubic centimeter of a 5 per cent suspension of red 

 cells is conveniently taken. This means that the cells after 

 washing are sedimented in the centrifuge and 1.0 c.c. of the 

 sediment is added to 19.0 c.c. of salt solution. (Some investi- 

 gators have worked with suspensions representing 5 per cent of 

 the original blood. Assuming the cells to constitute 50 per 

 cent of the blood volume, suspensions so made up are just half 

 as concentrated as the ones here used. In all the work here de- 

 scribed the term 5 per cent suspension is taken to represent 5 per 

 cent by actual volume of erythrocyte sediment in salt solution.) 



Definite amounts of sensitizer and of alexin are necessary to 

 lake completely one cubic centimeter of such a suspension, and it 

 is necessary for accurate experimentation to determine for each 

 set of reagents the minimal amounts necessary to accomplish 



