The enhancement phenomenon and its mechanisms
Historically, the enhancement phenomenon (enhancement phenomenon) was first discovered in the early 20th century while working with tumor grafts, such as rat sarcomas and mouse mammary carcinomas. The essence of the process is that preliminary administration of hyperimmune serum containing antibodies to the recipient causes the tumor to engraft and grow much more intensively.
Later, this effect was successfully reproduced on normal homologous skin flaps. According to the theory of tolerance, an excess amount of antibodies or antigens blocks specific cell proliferation centers, causing their death. This halts the inductive and productive phases of immunogenesis, establishing artificial tolerance in the organism.
Application of antilymphocytic serum
Antilymphocytic serum is being actively introduced into clinical practice as a potent immunosuppressive agent of biological origin. It is obtained from animals such as horses or rabbits, which are pre-immunized by repeated administration of human lymphocytes.
This preparation contains preformed specific antibodies that effectively suppress the activity of the recipient's lymphoid tissue. Physicians use this agent to suppress tissue incompatibility reactions and prevent the rejection of transplanted organs and tissues.
Surgical methods of immunosuppression
In addition to sera, direct surgical methods targeting the organs of the lymphatic system are used in practice. These include the removal of key immune organs:
- Splenectomy (removal of the spleen);
- Removal of the thymus gland (thymectomy);
- Excision of lymph nodes.
Nevertheless, at present, a universal and universally recognized reliable surgical method for the complete suppression of innate immunity has not yet been found, and research in this area continues.
Briefly: answers to topical questions
What modern monoclonal antibodies are used as biological immunosuppression?
Sources classify the following monoclonal antibody preparations used as immunosuppressants/to prevent rejection:
- To the IL-2 receptor (CD25): daclizumab, basiliximab — block IL-2 receptors on T-lymphocytes and prevent/block their activation.
- To the CD3 molecule: anti-CD3 antibodies; only blocking antibodies are used in therapy. Muromonab-CD3 is listed in the immunosuppressant classification.
- To CD52: alemtuzumab — causes lysis of lymphocytes and their clearance from the bloodstream.
- To TNF-α: etanercept, infliximab.
A promising direction is antibodies against co-stimulatory receptors, for example, CD80.
For what purpose is splenectomy performed when preparing a recipient for transplantation?
Splenectomy is performed as a surgical method of immunosuppression during transplantation. Sources classify the removal of the spleen among surgical methods for suppressing the recipient's immune response/immunity.
Which lymphocyte subpopulations are predominantly affected by antilymphocytic serum?
Antilymphocytic serum selectively acts on lymphoid cells circulating in the blood, enveloping and destroying them. At the same time, it has a weak effect on lymphocytes located in the lymph nodes and bone marrow.
Serum + Surgery = Graft success (ALS takes antibodies from animals against human lymphocytes, while the scalpel removes lymphoid organs — the thymus and spleen).
Class and exam questions
What lies at the basis of the enhancement phenomenon?
The enhancement phenomenon is based on the action of humoral antibodies. An excess of antibodies or antigens blocks specific cell proliferation centers, leading to their death and the induction of tolerance.
How is antilymphocytic serum obtained?
It is obtained from laboratory animals, such as horses or rabbits, by immunizing them with repeated injections of human lymphocytes.
Which surgical procedures are used for immunosuppression?
To suppress immune responses, removal of the organs of the lymphatic system is used: splenectomy, removal of the thymus gland (thymectomy), and lymph nodes.
What else to study on this topic
- History of studying the enhancement phenomenon on tumor grafts
- Theory of tolerance and blocking of cell proliferation centers
- Features of obtaining antilymphocytic serum from animals
- The role of the thymus and spleen in the immune response
- Challenges in finding reliable methods for suppressing innate immunity
Master the complete topic in the "Topographic Anatomy" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Biological methods of immunosuppression" and 2,777 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 91 video lessons on the subject
Other topics in the section "Internal Organ Transplantation (Overview)"
Free video lessons: topographic anatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.