78 LABORATORY COURSE IN SERUM STUDY 



Set up the following experiment in agglutination tubes : 



Tube No. 1 Serum (1-20) 0.5 c.c. + Typhoid suspension 0.5 c.c. 



2 Serum (1-100) 0.5 c.c. + Typhoid suspension 0.5 c.c. 



3 Serum (1-500) 0.5 c.c. + Typhoid suspension 0.5 c.c. 



4 Serum (1-2000) 0.5 c.c. + Typhoid suspension 0.5 c.c. 



5 Salt solution 0.5 c.c. + Typhoid suspension 0.5 c.c. 



6 Serum (1-20) 0.5 c.c. + Colon suspension 0.5 c.c. 



7 Serum (1-100) 0.5 c.c. + Colon suspension 0.5 c.c. 



8 Serum (1-500) 0.5 c.c. + Colon suspension 0.5 c.c. 



9 Serum (1-2000) 0.5 c.c. + Colon suspension 0.5 c.c. 



10 Salt solution 0.5 c.c. + Colon suspension 0.5 c.c. 



Incubate one hour at 37 C. and record the results. 



B. ABSORPTION 

 Place in small centrifuge tubes : 



A. Serum (1-10) 1.5 c.c. + Thick typhoid suspension 1.5 c.c. 



B. Serum (1-10) 1.5 c.c. + Thick colon suspension 1.5 c.c. 



Incubate one hour. (For complete absorption, incubation in the 

 thermostat should be followed by 12 or more hours in the refrigerator.) 

 Centrifugalize at high speed and remove the clear supernatant fluid. 1 



C. TITRATION OF THE SERUM AFTER ABSORPTION 



The supernatant fluid obtained by centrifugation should be tested 

 undiluted (it corresponds to a 1-20 dilution of the original serum) against 

 the same organism used for absorption, and as the absorption is often 

 incomplete after this short incubation a similar test should be set up 

 of the supernatant fluid diluted 1-5 (corresponding to a 1-100 dilution 

 of the original serum). The supernatant fluid should also be tested 

 against the organism not used in absorption in the highest dilution in 

 which agglutination was found in the preliminary titration. 



1. Supernatant fluid A 0.5 c.c. + Typhoid suspension 0.5 c.c. 



2. Supernatant fluid A (1-5) 0.5 c.c. + Typhoid suspension 0.5 c.c. 



3. Supernatant fluid A 0.5 c.c. + Colon suspension 0.5 c.c. 



4. Supernatant fluid in high- 



est dilution in which it 

 agglutinated colon in pre- 

 liminary titration 0.5 c.c. + Colon suspension 0.5 c.c. 



1 It should be noted that absolutely complete removal of agglutinins is not 

 possible except by many times repeated absorption. 



