Page 344 - The Veterinary Laboratory and Field Manual 3rd Edition

Serology and immunology 313

Figure 6.7(b) The quantitative precipitin test. When an increasing amount of soluble antigen is added to a
constant amount of antibody, antigen–antibody complexes of different ratios are formed. At equivalence,
all of the antigen–antibody is precipitated yielding the greatest amount of insoluble precipitin. Source:
M. Sarjoon Abdul-Cader, University of Calgary, Canada.

Example of the tube agglutination test in tubes No. 2 to No. 8, add 0.5 ml of phenol
saline solution.
Materials • Deliver 0.2 ml serum to be tested in tube No.
• 37°C water bath 1 and mix thoroughly. Next transfer 0.5 ml
• microtitre pipettes (200–1000 µl) of suspension from tube No. 1 to tube No. 2
• tubes and racks. and mix. T wofold serial dilution is continued
to tube No. 8 from which 0.5 ml is discarded.
Hence, tubes No. 1 to No. 8 contain diluted
Method
serum from 1 : 5 to 1 : 640.
• Place tubes in a rack and number (1–10). • Into each tube deliver 0.5 ml of the antigen
• In tube No. 1 put 0.8 ml of phenol saline so that the final dilution of sera is now 1 : 10
solution (0.85% NaCl and 0.5% phenol) and to 1 : 1280.

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