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Biomedical subjects

H Bazin

Publications and source records attributed to H Bazin.

At least 289 records · Page 16Linked to original sources
PubMed1979

The effect of age on IgE production in rats.

Inbred BN-rats were immunized at different ages with a standardized amount of ovalbumin and a1(OH)3. The specific IgE antibody response and total serum IgE levels were significantly influenced by age. The IgE antibody response increased to a maximum in 2-month-old rats and decreased progressively at a more advanced age. Total serum IgE levels increased progressively from the age of 1 month to the age of 5 months and decreased again at the age of one year.

Aging↗
PubMed1979

[The LOUVAIN rat and its importance in cancerology].

The LOUVAIN rat model is characterized by a high incidence of spontaneous tumors which is extremely rare in animals. Presently, the spectrum of monoclonal immunoglobulins synthetized by these tumors is the largest ever discovered in animals. Particularly, the LOUVAIN rat tumors produced the only IgD and IgE monoclonal immunoglobuling discovered in an animal species up to now. The contributions of this model to experimental cancerology were multiple: some of them originate in its high incidence, its anatomopathological type or its production of homogenous proteins, others, in the antigenic properties of the monoclonal immunoglobulins synthetized by these tumors, allowing the study of their natural analogues in absolutely new experimental conditions.

Animals↗
PubMed1979

Serum IgE levels in rats infected with Dipetalonema viteae L3 larvae.

Serum IgE levels were measured by radioimmunoassay in rats infected with various doses of L3 infective stage larvae of Dipetalonema viteae. A high stimulation in total serum IgE levels was found with minute doses as well as with large doses of parasite, and IgE levels remained elevated for several months. No further increase in IgE levels was induced by a secondary infection.

Animals↗
PubMed1978

Rapid disappearance from serum of intravenously injected rat myeloma IgA and its secretion into bile.

Intravenously injected monoclonal rat IgA is first removed from rat serum at a very fast rate (93% in 4 h), then at a much slower rate (t/2 = 24 h). The rapid initial disappearance is thought to be due in part to secretion into rat bile. This was demonstrated by rat liver perfusions with semisynthetic medium containing diluted (1:200) IgA myeloma serum. During perfusion, the cannulated bile displayed increasingly high levels of this IgA, with a bile to medium ratio of 38 after 1 h of perfusion; at the same time, there was a 40% drop of the rat monoclonal IgA concentration in the medium, which was not observed for rat IgG2a and albumin. All of the monoclonal biliary IgA was bound to secretory component. The rat liver is thus able to actively secrete a monoclonal IgA from the circulation into bile against a strong concentration gradient.

Animals↗
PubMed1978

Eosinophil-dependent cytotoxicity in rat schistosomiasis. Involvement of IgG2a antibody and role of mast cells.

Using Schistoma mansoni schistosomula collected in vitro and sensitized with 42-day-infected rat serum, normal rat peritoneal cells enriched in eosinophils were proven to subsequently adhere to and kill the schistosomula within 24 to 48 h. The cell-dependent, heat-stable antibody in infected rat serum reached a peak between 30 and 42 days after infection. Inhibition experiments with aggregated immunoglobulins indicated the role of IgG2a antibody in the adherence of eosinophils to sensitized schistosomula. The immune absorption technique showed that IgG2a antibody was involved in the mechanism of cytotoxicity of effector to target cells, whereas the role of IgE antibody could be excluded. Ultrastructural studies revealed the constant presence of eosinophils and mast cells in contact with schistosomula. The use of purified cell populations showed that the cytotoxic effect of the original cell population was significantly decreased after depletion of mast cells and partially restored after addition of mast cells. These observations, together with those concerning the role of IgE immune complexes in macrophage cytotoxicity, suggest the possible participation of anaphylactic antibodies in immunity to schistosomes in the rat.

Animals↗
PubMed1978

Effect on rat IgA synthesis by isotypic suppression with an anti-rat delta heavy chain serum.

It is highly probable that IgA precursor cells have IgD receptors during their ontogeny, however isotypic suppression with anti-delta serum did not demonstrate this possibility at least in our experimental conditions. Moreover, isotypic suppression with anti-delta serum seems ineffective in diminishing the serum levels of Ig classes other than IgD under these conditions, as IgM, IgE and IgG serum levels were relatively unaffected, at least during the first month of the rat life.

Animals↗
PubMed1978

TB mice. A model of high and long lasting reaginic responders.

Reaginic (IgE) antibodies are normally difficult to induce in laboratory rodents. The TB inbred mice constitute an exceptionally suitable model for the study of reaginic responses because of their ability to mount a strong and long lasting (over 4 months) IgE antibody response to hapten carrier conjugates, such as DNP3-OVO, administered in the presence of adjuvant. The maximum individual PCA titres determined for the sera of 8 animals after primary sensitization were in the range of 2,048 to 65,536 (geometric mean: 9,733) and after secondary sensitization the maximum individual PCA titres augmented to a level of 8,192 to 131,072 (geometric mean: 50,490).

Adjuvants, Immunologic↗
PubMed1978

Incidence of spontaneous ileocecal immunocytomas in hybrids of LOU/C rats and rat strains with low spontaneous tumor incidence.

Monoclonal immunoglobulin-secreting tumors (immunocytomas or plasmacytomas) appear in many species, but they occur at a low incidence and usually originate in lymphoid tissues. However, in the rat, the incidence of malignant spontaneous immunocytomas (or plasmacytomas) was high and the tumors consistently arose in the ileocecal lymph nodes. In inbred LOU/C/Wsl rats, these immunocytomas developed in twice as many males (31%) as females (16%). The susceptibility of the rats to immunocytoma was under genetic control; e.g., LOU/C/Wsl rats had a dominant locus (or loci) of susceptibility that could induce immunocytoma in inbred AUG/Wsl or inbred A X C9935/Wsl rats. However, inbred Okamoto/Wsl rats had at least one dominant locus of resistance that did not exist in LOU/C/Wsl, LOU/M/Wsl, AUG/Wsl, or A X C9935/Wsl rats.

Animals↗
PubMed1978

Effect of antigen dose on the secondary IgE response in BN rats.

Inbred Brown Norway rats were immunized at day 0 with a single dose of ovalbumin and 1 mg A1(OH)3. Various doses of ovalbumin without adjuvant were given at day 28. The secondary IgE antibody was antigen dose-dependent. Total serum IgE levels decreased after immunization and during the IgE antibody response.

Aluminum Hydroxide↗
PubMed1978

Rat ileocecal immunocytoma. An ultrastructural study with special attention to the presence of viral particles.

Fifteen spontaneous immunocytomas originating in the ileocecal lymph nodes of Lou/C/Wsl rats were studied by means of electron microscopy. The histology was characteristic, the tumor being formed by an accumulation of large, rounded cells with slightly eccentric ovoid nuclei, large nucleoli, and finely condensed chromatin along the nuclear walls; the cytoplasma was rich in polyribosomes. The appearance of the rough endoplasmic reticulum was apparently the same whether or not the tumor was secretory. Its development varied from one cell to another, and in only a small proportion of cells did it attain any considerable volume. In all the tumors examined, we noted the presence of intracisternal A-particles. In its morphology, the rat immunocytoma resembled the plasmacytomas induced in mice, and it also resembled certain human tumors such as Burkitt's lymphoma.

Animals↗
PubMed1978

IgE in experimental schistosomiasis. II. Quantitative determination of specific IgE antibodies against S. mansoni: a follow-up study of two strains of infected rats. Correlation with protective immunity.

Parasite specific IgE antibodies in rats infected with Schistosoma manoni were measured by passive cutaneous anaphylaxis (PCA) reactions and by the technique of immuno-adsorption. Two strains, one a low IgE producer (Fischer rats) and the other a high IgE producer (Hooded-Lister rats) were studied. In Fischer rats, a time course study of the occurrence of IgE antibodies and resistance to reinfection was made. Parasite specific IgE levels measured by immuno-adsorpiton were much lower than total IgE levels and a similar percentage of specific IgE (about 8%) was in the two strains.IgE antibodies were maximum at day 30 and day 60 after infection; however, a third peak at day 90 was observed only in Fischer rats. Some discrepancies between results obtained by PCA and immunosorbent techniques have been observed, which could be explained by differences in the affinity of IgE antibodies during infection or by the presence of total IgE in the PCA assay. There was a close parallelism between specific IgE antibodies levels and the course of immunity in Fischer rats. This parallelism supports the view that IgE could play a pre-eminent role in protective immunity in rat schistosomiasis.

Animals↗
PubMed1978

[Contribution to the study of ontogeny of the cells synthetizing IgE class immunoglobulins (author's transl)].

It is known that a treatment, initiated with birth, of repeated injections of anti-mu heavy chain sera leads in mice to considerable decrease of the serum level of the various classes of immunoglobulins : IgM, IgA, IgG1, IgG2. A similar treatment led to similar results in rats but, in addition, made it clear that the IgE serum level was also decreased by the treatment. Moreover, a series of injections of an anti-rat IgD serum also produced a significative decrease of the IgE serum level. The results suggest that the precursor cells of the IgE plasma cells are bearing molecules of IgM and IgD classes on their membrane.

Animals↗
PubMed1978

Ontogeny of IgE-bearing lymphocytes in the rat.

IgE-bearing lymphocytes were detected by immunofluorescence in the spleen of neonatal Hooded Lister strain rats within 24 hr after birth. The same cells were detected in the bone marrow as early as the 4th day after birth. Both fetal spleen and liver obtained 1 day before birth contained IgM-bearing cells but no detectable IgE-bearing cells. The proportion of IgE-bearing cells in the spleen and bone marrow increased during the neonatal period and reached an adult level within 3 to 4 weeks after birth. In adult Hooded Lister rats, IgE-bearing cells were 3 to 6% of total spleen cells and 1.5 to 2.2% of bone marrow cells. Most of the IgE-bearing cells from bone marrow cells. Most of the IgE-bearing cells from both newborn and adult animals carried IgM determinants on their surface. Capping experiments showed that epsilon chain determinants and mu chain determinants belonged to separate molecules. IgG2a-bearing lymphocytes were detected in the neonatal spleen as early as the 4th day after birth, but a significant number of these cells was not detected in the bone marrow until the 4th week. In newborn spleen the percentage of IgE-IgM double bearing cells was higher than that of IgG2a-bearing cells.

Animals↗
PubMed1978

Transplantable IgD immunoglobulin-secreting tumors in rat.

The LOU/C/Wsl rat inbred strain presents a high incidence of spontaneous malignant ileocecal immunocytomas or monoclonal immunoglobulin-secreting tumors. Some tumors have been transplanted in histocompatible animals over years without any change in their secretion products. Among approximately 600 different monoclonal proteins we have studied so far, we recognized six showing properties different from those of rat IgM, IgA, IgE, or IgG classes, and characteristic of the IgD class.

Animals↗
PubMed1978

Rat mast cell-eosinophil interaction in antibody-dependent eosinophil cytotoxicity to Schistosoma mansoni schistosomula.

The involvement of IgG2a antibodies and mast cells in antibody-dependent eosinophil cytotoxicity suggested a possible interaction between mast cells and eosinophils for in vitro killing of Schistosoma mansoni schistosomula. Cell purification procedures showed that a minimum ratio of mast cells was required to obtain eosinophil cytotoxicity. The incubation of mast cells with heat-aggregated IgG2a immunoglobulins before addition to a mast cell-depleted eosinophil population induced a significant degree of inhibition of cytotoxicity, Similarly, the heat-aggregated IgG2a Fc fragment had a strong inhibitory effect whereas incubation of mast cells with Fab fragment failed to inhibit the cytotoxic effect. The Fc portion of IgG2a immunoglobulins therefore seemed to be involved in binding to the mast cell surface. Furthermore, it was demonstrated that soluble mediators released after mast cell activation either by compound 48/80, or by IgE, or IgG2a-dependent reaction had the same effect as intact mast cells. These observations suggest that the eosinophil-dependent cytotoxicity mechanism requires a signal provided by soluble mast cell mediators in addition to antibody.

Animals↗