Biomaterial Database

Immunological tolerance to the thymus-independent antigen dextran can be abrogated by thymus-dependent dextran conjugates: evidence against clonal deletion as the mechanism of tolerance induction. 1978

G Möller, and C Fernandez

Tolerance to the alpha1--6 epitope of native dextran B512 was found to be very stable and could not be broken by the injection of dextran conjugated to several substances, such as protein A, keyhole limpet haemocyanin, edistin, concanvalin A or Staphylococcus bacteria, strain Cowan. However, when tolerant mice were injected with dextranase, all the above conjugates induced a strong anti-alpha1--6 immune response. In contrast, native dextran itself never induced a response in tolerant, dextranase-treated mice. It was concluded that tolerance only affects the specific B-cell subpopulation that can respond to the polyclonal B-cell-activating (PBA) property of dextran, whereas other specific B cells having PBA receptors for, e.g., signals delivered by collaborating T cells remain in a resting state. These B cells can respond in a specific immune response against the tolerogen after removal of the antigen, which blocks the Ig receptors and therefore prevents them from passively focusing the antigen. Thus, immunological tolerance is not caused by clonal elimination of the antigen-specific clone, but only affects a small subfraction of cells with Ig receptors against the tolerogen.

UI	MeSH Term	Description	Entries
D007108	Immune Tolerance	The specific failure of a normally responsive individual to make an immune response to a known antigen. It results from previous contact with the antigen by an immunologically immature individual (fetus or neonate) or by an adult exposed to extreme high-dose or low-dose antigen, or by exposure to radiation, antimetabolites, antilymphocytic serum, etc.	Immunosuppression (Physiology),Immunosuppressions (Physiology),Tolerance, Immune
D007114	Immunization	Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).	Immunologic Stimulation,Immunostimulation,Sensitization, Immunologic,Variolation,Immunologic Sensitization,Immunological Stimulation,Sensitization, Immunological,Stimulation, Immunologic,Immunizations,Immunological Sensitization,Immunological Sensitizations,Immunological Stimulations,Sensitizations, Immunological,Stimulation, Immunological,Stimulations, Immunological,Variolations
D008815	Mice, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.	Inbred Mouse Strains,Inbred Strain of Mice,Inbred Strain of Mouse,Inbred Strains of Mice,Mouse, Inbred Strain,Inbred Mouse Strain,Mouse Inbred Strain,Mouse Inbred Strains,Mouse Strain, Inbred,Mouse Strains, Inbred,Strain, Inbred Mouse,Strains, Inbred Mouse
D011506	Proteins	Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.	Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002999	Clone Cells	A group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence. (From King & Stansfield, Dictionary of Genetics, 4th ed)	Clones,Cell, Clone,Cells, Clone,Clone,Clone Cell
D003208	Concanavalin A	A MANNOSE/GLUCOSE binding lectin isolated from the jack bean (Canavalia ensiformis). It is a potent mitogen used to stimulate cell proliferation in lymphocytes, primarily T-lymphocyte, cultures.
D003910	Dextranase	Enzyme that hydrolyzes DEXTRAN to OLIGOSACCHARIDES.	Endo-Dextranase,Glucanase 447-G,Endo Dextranase,Glucanase 447 G
D003911	Dextrans	A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.	Dextran,Dextran 40,Dextran 40000,Dextran 70,Dextran 75,Dextran 80,Dextran B-1355,Dextran B-1355-S,Dextran B1355,Dextran B512,Dextran Derivatives,Dextran M 70,Dextran T 70,Dextran T-40,Dextran T-500,Hemodex,Hyskon,Infukoll,Macrodex,Polyglucin,Promit,Rheodextran,Rheoisodex,Rheomacrodex,Rheopolyglucin,Rondex,Saviosol,Dextran B 1355,Dextran B 1355 S,Dextran T 40,Dextran T 500
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia