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Results for “Models, Immunological”

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At least 19 recordsLinked to original sources
PubMed1994

High-dimensional simulation of simple immunological models.

We propose a simple model for idiotypic-antiidiotypic immunological networks which represents a simplification of the model originally suggested by Stewart & Varela, and de Boer, van der Laan & Hogeweg. Window cellular automata enlarge the antibody concentration if the influence of the immediate neighborhood lies between 70 and 99% of its maximum value; in addition random recruitment is possible. We simulate the model on large square lattices as well as in higher dimensions. The results are in qualitative agreement with those of the earlier model. Moreover, in five to ten dimensions we find phase separation for not too large recruitment, which then leads to domains growing to "infinity" for infinite times.

Animals↗
PubMed1997

Intracorneal bovine albumin: an immunologic model of corneal angiogenesis.

BACKGROUND: We characterized the neovascularization that follows the intracorneal injection of bovine albumin (BA) in rabbits as a model of corneal angiogenesis. METHODS: New Zealand white rabbits received intracorneal injections of phosphate-buffered saline with and without various amounts of BA. The rabbits were co-sensitized or pre-sensitized by intramuscular BA or were not sensitized. The corneal vascular response was quantified by ranking photographs taken periodically after the injection. RESULTS: In pre-sensitized animals, blood vessels were apparent within 4 days and reached maximum intensity 14 days after the intracorneal injection. Corneas also vascularized in non-sensitized rabbits, but a larger dose (> 0.2 mg BA) was required than in pre-sensitized animals (> 0.02 mg BA). Vascularization began later in non-sensitized animals and was less extensive than in pre-sensitized animals. CONCLUSION: The intracorneal injection of BA is a reproducible model of corneal angiogenesis in rabbits and should allow the involved immunological mechanisms to be elucidated.

Animals↗
PubMed1981

An immunological model of epilepsy: seizures induced by antibodies to GM1 ganglioside.

Following observations that the intracerebral injection into rats of antiserum to brain gangliosides resulted in recurrent epileptiform activity and that seizure activity was not seen if antibodies were removed by absorption of the antiserum with pure GM1 ganglioside, a study was undertaken to establish characteristics of the immunological agents used to produce this model of epilepsy. It was determined that the potencies (antibody titers with GM1 ganglioside) of antiganglioside sera can be correlated with the intensities of epileptiform activity they induce; that immunoglobulin fractions from antiganglioside sera are even more effective biologically than the antisera; and that antibodies to GM1 ganglioside purified by affinity chromatography can also induce recurrent epileptiform discharges but are not as effective as either native antiserum or immunoglobulin fractions.

Animals↗
PubMed1978

[Cervix carcinoma as an immunological model. Part 2. In vitro studies and HLA system typing].

Carcinoma of the cervix uteri is one of the most important tumors in women. The tumor induces an immunological defense reaction against itself in the tumor host. The round cell infiltrate at the tumor invasion line, which predominantly consists of small lymphocytes is the morphological equivalent of this interrelationship. In the lymph-nodes of the drainage area of the tumor certain patterns of reaction can be differentiated, which may be interpreted as humoral or cellular immune reactions. Cellular immune reactions in lymph-nodes of patients operated according to the method of Wertheim-Meigs were correlated with a better prognosis of the tumor disease. The hypothesis of an involvement of the HSV-type II in the genesis of the cervical carcinoma is supported by the increased incidence of antibodies against the virus. Therewith, relations between the stage of disease and the age of the patient were found as a possible basis for the virus hypothesis and the immune reaction to the tumor associated antigens an altered genetic situation may be presumed. Typing in the HLA-system demonstrates an accumulation of the frequency of the antigen B12 in patients with carcinoma of the cervix. These investigations may lead to a differentiated outlook with regard to the detection of risk groups and therapeutical consequences for cervical cancer.

Antibodies, Viral↗
PubMed1996

Inability to establish ectopic endometrium in a natural killer cell-deficient murine model. Immunologic, histologic and histochemical assessment.

OBJECTIVE: To investigate what effect natural killer (NK) cells have on the implantation of heterologous endometrial scrapings. STUDY DESIGN: Anti-asialo GM1 (AA-GM1) anti-sera have been shown to eliminate NK cell activity in various strains of rats and mice. Either AA-GM1 antibodies (+) or rabbit antiglobulin (-) was administered to beige mice (NK cell deficient) or beige control mice (not NK cell deficient of the same strain). The heterologous endometrial scrapings were prepared by scraping seven pairs of uterine horns from normal mice of the same strain. Beige and normal mice were then injected intraperitoneally every 3 days with the heterologous endometrial scraping and antibodies for a period of 50 days. The four experimental groups (n = 10 per group) can be summarized as being beige (+), beige (-), normal (+) and normal (-). RESULTS: There was no evidence of ectopic endometrial tissue in any of the four test groups by histologic examination or by using immunohistochemical staining techniques. Histologic evidence of an impaired immune response was clearly demonstrated in the beige mice receiving AA-GM1 antibodies. CONCLUSION: Using this model, a deficiency of NK cell activity did not appear to enhance the implantation of endometrial tissue on the abdominal peritoneum of mice.

Animals↗
PubMed1980

Action of gold salts in some inflammatory and immunological models.

Several gold salts were compared in kaolin-induced rat paw oedema, u.v. erythema in guinea pigs, delayed type hypersensitivity and humoral immunity in mice, and adjuvant-induced arthritis in the rat. In the latter the additional parameters of serum gold and copper levels and lysosomal enzyme activity were determined. In addition, the in vitro inhibition of several lysosomal enzymes derived from mouse macrophages was studied. The gold compounds examined were aurothiomalate, aurothioglucose, triethylphosphine gold chloride (SK & F 36914) and its glucopyranoside derivative (SK & F D-39162), triphenylphosphine gold chloride and sodium gold chloride dihydrate. SK & F 36914 and SK & F D-39162 has significant activity after oral dosage upon paw kaolin and u.v. erythema in rats and guinea pigs, respectively. Gastric swelling also occurred. In Wistar rats, adjuvant arthritis was little affected by the gold salts but in the Lewis rats there was suppression. In both strains there was less elevation in serum copper levels with treatment by SK & F 36914 and SK & F D-39162, but not by aurothiomalate. None of the compounds had any measurable effect on delayed hypersensitivity or humoral antibody levels in mice. The in vitro activities of cathepsin B1 and cathepsin D were inhibited by all the gold compounds. Reactivity of gold compounds with glutathione and cysteine in vitro was dependent on compound solubility and the nature of the gold ligand. Considerable differences exist between the profiles of activity for the different gold salts evaluated. These observations indicate that some gold salts do possess anti-inflammatory activity with a potency similar to that of indomethacin.

Animals↗
PubMed1982

Immunological model of epilepsy. Epileptiform activity induced by fragments of antibody to GM1 ganglioside.

Antibodies to GM1 ganglioside injected into the sensorimotor cortex of the rat induce recurrent epileptiform activity. We now find that the divalent F(ab')2 and monovalent Fab' fragments derived from antiganglioside IgG molecules are able to induce epileptiform seizures. This result supports the view that the binding of antibodies to ganglioside receptors in the synaptic membrane is sufficient in itself to initiate changes in membrane processes which lead to epileptiform spiking. These changes do not appear to be dependent on linking of ganglioside receptors or on the presence of serum factors such as complement.

Animals↗
PubMed1998

An immunological model connecting the pathogenesis of stress, depression and carcinoma.

Recently there has been considerable conjecture in the literature concerning a possible relationship between stress, depression and bereavement, and carcinoma. We shall propose a causal model in which the relationship between stress, depression and carcinoma is clarified. This relationship is grounded on dysregulation of the inflammatory cytokines in stress and depression. Stress is associated with increased expression of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), and reduced expression of IL-2, interferon-gamma (IFN-gamma), major histocompatability complex (MHC) class II molecules and natural killer cell activity (NKA). Depression is associated with elevated IFN-gamma and IL-1 beta, downregulated IL-2, and reduced NKA. Most organ-related carcinomas are associated with elevated TNF-alpha, which inhibits the activity of protein tyrosine phosphatase (PTPase), the enzyme that initiates activation of the MHC class I pathway. Sustained elevation of TNF-alpha inhibits the activity of PTPase which results in diminished expression of the MHC class I antigen on the cell surface and thus, malignant cells escape immune surveillance. Therefore, stress and depression can foster tumor progression by means of inhibiting the expression of MHC class I and II molecules and through the reduction of NKA.

Cytokines↗
PubMed1999

Pargyline conjugate-induced long-term activation of monoamine oxidase as an immunological model for depression.

We describe an animal model of long-term depression based on active immunization of albino rats against BSA-conjugated inhibitor of monoamine oxidase, antidepressant, pargyline. Immunization resulted in anti-pargyline antibody formation and significant activation of monoamine oxidase A in brain. Immunized rats demonstrated potent decrease of motor, orientation and exploratory activity, increase of the immobility time ("despair") in Porsolt test, as well as notable signs of fear and anxiety in elevated plus maze. The cognitive processes were not significantly affected: the speed of learning with negative and positive reinforcement was not diminished. Complex effect on craving for alcohol (long-term suppression after short-term increase) was also demonstrated. The long-term (more than 45 days) depression achieved in this model makes it potentially important tool for testing new antidepressant pharmaceuticals.

Animals↗
PubMed1988

Immunologic modeling of a 75-kDa malarial protein with carrier-free synthetic peptides.

A protein of 75 kDa is produced in large quantities by the human malarial parasite Plasmodium falciparum and is present on the surface of the merozoite, whose function is to infect erythrocytes. Based on nucleotide sequence coding for 40% of this protein, two nonoverlapping model peptides 13 and 19 residues long were synthesized, coupled to a keyhole limpet hemocyanin carrier, and used to immunize rabbits. Although both antisera had high titers of anti-peptide antibodies, only that raised against the 13-residue peptide showed good reactivity against the original protein. Although the 19-mer adopted the helical secondary structure predicted for the corresponding protein region, antisera against this peptide reacted with the native protein weakly or not at all. Concluding that the poor anti-protein reactivity was due to modification of lysine-containing epitopes by glutaraldehyde conjugation, we used a carrier-free 28-residue peptide presented as a 56-residue disulfide-bonded dimer to model the same region. This peptide, in contrast to the conjugated 19-mer, stimulated the production of IgG antibodies that reacted at high dilution with the authentic protein in immunoblots, ELISA, and radioimmunoprecipitation assays. These data indicate that large carrier-free peptides may be successfully used as immunogens. In addition, our results show that this strategy may greatly improve the ability of conjugation-sensitive peptides to stimulate antibodies reactive with the original protein and therefore has substantial practical application.

Animals↗