Nature and properties of anticlon reagents
Anti-A and anti-B цоликлоны are used in surgery and transfusiology instead of standard isohemagglutinating sera. By their nature, they are monoclonal antibodies belonging to the IgM class.
They are produced by special cells—hybridomas. A hybridoma is the result of fusing mouse B-lymphocytes (which produce antibodies) with mouse myeloma cells. The ready-to-use reagent is a diluted ascitic fluid obtained from carrier mice of such hybridomas.
The main advantage of цоликлоны is that they provide a faster and more pronounced agglutination reaction. The preparations are available in liquid form (in vials or ampoules), with anti-A colored red and anti-B colored blue. The reagents must be stored in a refrigerator at a temperature of 2 to 8 °C, and their shelf life is 2 years.
Test procedure
To obtain reliable results, the methodology must be strictly followed. The reaction is carried out at an ambient temperature of 15 to 25 °C. A white porcelain plate or a marked dish is used as the working surface.
Step-by-step action algorithm:
- One large drop each of anti-A and anti-B цоликлоны is applied to the prepared surface.
- The blood to be tested is applied next to each drop of reagent. The volume of the blood drop must be 10 times smaller than the volume of the цоликлон drop.
- Using separate glass rods (or the corners of glass slides), the drops are carefully mixed.
- The plate is gently rocked for better interaction of the components.
Visually, the reaction usually begins to appear within the first 3–5 seconds. In positive cases, small red erythrocyte aggregates form, which quickly turn into large flakes. Final observation of the process and final evaluation are carried out within 2.5 minutes.
Interpretation of results
Evaluation of the AB0 blood group is based on the presence (+) or absence (–) of erythrocyte agglutination with a specific цоликлон. Four scenarios are possible:
- Group I (0): reaction is absent with both цоликлоны—anti-A (–) and anti-B (–). Conclusion: erythrocytes do not contain agglutinogens A and B.
- Group II (A): agglutination is observed only with anti-A (+) and is absent with anti-B (–). Conclusion: erythrocytes contain agglutinogen A.
- Group III (B): agglutination is absent with anti-A (–) and is observed with anti-B (+). Conclusion: erythrocytes contain agglutinogen B.
- Group IV (AB): clumping reaction occurs with both цоликлоны—anti-A (+) and anti-B (+). Conclusion: erythrocytes contain both agglutinogens A and B.
Additional control for group IV (AB)
If the test reveals a positive reaction with both reagents, blood group IV (AB) is preliminarily assigned. However, this result requires mandatory confirmation to exclude the phenomenon of nonspecific agglutination.
An isotonic sodium chloride (NaCl) solution is used for control. A large drop (0.1 ml) of physiological saline is applied to the plate and mixed with a small drop (0.01 ml) of the test blood. If agglutination is absent in this control drop, the validity of blood group IV is confirmed.
Note: If questionable agglutination occurs at any stage of the test, the цоликлон method is supplemented by the classic method using standard erythrocytes.
Briefly: answers to topical questions
What technical errors can lead to false agglutination when using цоликлоны?
Violations of the test methodology lead to false agglutination (false-positive result). The following main technical errors are distinguished:
- Drying of the drop—causes the formation of erythrocyte "rouleaux", leading to pseudo-agglutination.
- Cold agglutination—occurs when the reaction is carried out at ambient temperatures below 15 °C.
To prevent these errors, it is necessary to strictly maintain the temperature regime (above 15 °C) and add an isotonic sodium chloride solution to the drop with a questionable reaction.
To avoid mixing up the labels: anti-A is scarlet (red color), anti-B is blue.
Class and exam questions
Can the reaction be performed at 37 °C?
No, the test must be performed strictly at an ambient temperature of 15 to 25 °C.
In what proportion are blood and reagent mixed?
The drop of test blood should be approximately 10 times smaller than the drop of цоликлон.
What to do if agglutination is weakly expressed or questionable?
If questionable agglutination is present, it is necessary to proceed to blood typing using the standard erythrocyte method.
What else to study on this topic
- Structure and functions of monoclonal antibodies (IgM)
- Principles of hybridoma production in immunology
- Causes of nonspecific agglutination
- Methodology for blood typing with standard erythrocytes
- AB0 erythrocyte antigen system: agglutinogens and agglutinins
Master the entire topic in the "General Surgery" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Blood typing using цоликлоны" and 3,335 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 70 video lessons on the subject
Other topics in the section "CHAPTER 6. BLOOD TRANSFUSION"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.