126 LABORATORY COURSE IN SERUM STUDY 



Set up one tube (complement control) with 0.5 c.c. of sheep cells 

 and 0.5 c.c. of complement only, in order to make sure that the guinea 

 pig serum alone is not at all haemolytic. 



For the tests twice that amount of complement is used which just 

 gives complete haemolysis in 15 minutes. With average guinea pigs 

 0.25 c.c. gives this and 0.5 is used in the test. 



II. PREPARATION OF SERUM 



Inactivate at 56 C. for one half hour a known syphilitic and a 

 known normal serum and one or more sera to be examined. 



III. SETTING UP THE TESTS. PRIMARY INCUBATION 



Test tube racks with two rows of holes are used so that each serum 

 may have a "front" tube and a corresponding "back" tube. 



(a) Into each of a pair of 5 c.c. test tubes measure 0.1 c.c. of each of 

 the sera. 



(6) Into one (the front tube) of each pair measure a dose of diluted 

 antigen. (The dose is one third of the largest amount which by 

 previous titration has been found not to interfere with the action of the 

 amount of complement used in the test.) 



Into an extra tube measure two doses of antigen (antigen control 

 tube). 



(c) Into all tubes measure the predetermined dose of complement. 

 Shake each tube at once. Add enough saline to make the contents 

 of all the tubes approximately 2 c.c. 



(d) Incubate in water bath for one hour at 37 C. (With certain 

 antigens, as for instance with alcoholic heart extracts, somewhat more 

 delicate results can be obtained by a four hour preliminary incubation 

 in the ice box at 8-12 C. For class work, however, this is 

 impractical.) 



IV. ADDITION OF ILEMOLYTIC SYSTEM. SECONDARY INCUBA- 

 TION. READING OF RESULTS 



Into all tubes measure 0.5 c.c. of 5 per cent sheep cells to which 

 2 units of amboceptor have been added. Incubate at 37 C. Read the 

 results when the double antigen tube and all the serum control tubes 

 (i.e. those containing no antigen) are completely laked. 



Fill out a protocol of the degree of inhibition, if any, in the various 

 tubes : 



