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Biomedical subjects

G Wick

Publications and source records attributed to G Wick.

At least 307 records · Page 17Linked to original sources
PubMed1982

Avian lymphokines: 1. Thymic cell growth factor in supernatants of mitogen stimulated chicken spleen cells.

The present study provides first evidence for the presence of a thymic cell growth factor (TCGF) in supernatants (20 hrs) of mitogen (Con A) stimulated chicken spleen cells. 2 out of 3 batches of supernatant prepared according to a procedure originally described for the mouse system (10) induced a vigorous proliferative response of Con A prestimulated chicken spleen cells without significant mitogenic effect on unstimulated lymphocytes. No crossreactivity of this chicken-TCGF was observed with prestimulated murine lymphocytes, nor did potent mouse-TCGF preparations exhibit any proliferative effect on chicken cells. The implications of these data for both phylogenetic as well as practical experimental aspects are discussed.

Animals↗
PubMed1982

Monoclonal antibodies against human chorionic gonadotropin (hCG): I. production, specificity, and intramolecular binding sites.

Thirty-nine monoclonal antibody (MCA) producing hybridoma cell lines derived from fusions of mouse myeloma cells with spleen cells from mice immunized with human chorionic gonadotropin (hCG) have been established. Their products have been tested in radioimmunoassays using 125I-labeled hCG, luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), the alpha (alpha) and beta (beta) subunits of hCG and LH, and the C-terminal peptide 109-145 (CTP) of CG. All MCA were, in addition, tested in indirect immunofluorescence (IIF) on paraffin sections of human pituitary glands. According to the intramolecular localization of the determinants recognized, three main groups of MCA can be distinguished: 1) MCA directed against epitopes on the alpha-chain(alpha-MCA), 2) MCA directed against beta-chain determinants(beta-MCA), and 3) MCA reacting with a conformational determinant only present on the native hormone and not on either subunit (conformational-MCA). All alpha-MCA cross-react with human LH, FSH, and TSH. The beta-MCA do not react with FSH or TSH, but do react to a varying degree with LH. The conformational-MCA show no binding of labeled FSH or TSH and very little or no cross-reactivity with LH. (Am J Reprod Immunol. 1982; 2:212-216.)

Animals↗
PubMed1982

Effector mechanisms in the spontaneous autoimmune thyroiditis of obese strain (OS) chickens: analysis of cytotoxic cells.

Different forms of cellular cytotoxicity that may constitute potential effector mechanisms in the spontaneous autoimmune thyroiditis (SAT) arising in Obese strain (OS) chickens have been investigated. A microcytotoxicity assay (MCA) employing 51Cr-labelled-, thyroglobulin (Tg) coated-chicken red blood cells (Tg-CRBC) was used to detect cells mediating Tg-specific direct cellular cytotoxicity (DCC). Tg-CRBC presensitized with anti-Tg autoantibody (Tg-AAB) obtained from high titer OS sera served as targets for antibody-dependent cell-mediated cytotoxicity (ADCC). Tannic acid-only treated CRBC (TA-CRBC) were used simultaneously as specificity controls for DCC and also as targets for cells eliciting spontaneous cellular cytotoxicity (SCC) to surface-modified normal cells. The results demonstrated that Tg-specific cytotoxic cells exist in the OS and thus represent an effector mechanism in SAT, in addition to the previously well-documented role of antibody. This DCC appears to be unrelated to the presence and titer of circulating Tg-AAb. It is present in highest levels in the peripheral blood of OS chickens, but in only 55% of the animals tested, indicating either a secondary importance to humoral immunity in the disease process or the possibility of different effector mechanisms prevailing in different birds. There were no overall differences in ADCC between OS and normal chickens when the two strains were considered as a whole. Chronological analysis, however, revealed very low ADCC in the peripheral blood of young OS birds, followed by a later elevation above that in the normal control chickens. Destruction of the gland by ADCC may be initiated via maternally-derived of in situ-produced anti-Tg antibody. No overall significant differences in SCC were observed between OS and normal chickens.

Animals↗
PubMed1982

Tissue localization of lymphocyte surface antigens and receptors for immunoglobulin G Fc and complement in the chicken.

Frozen sections of chicken lymphoid organs were examined for lymphocyte surface antigens by antisera to T and B lymphocytes (ATS;ABS), and for the presence of immunoglobulin (Ig) G Fc and complement receptors (FcR;CR) by hemadsorption with sheep erythrocytes (E) coated with chicken IgG(EA), and E coated with rabbit IgG and chicken complement (EAC). In the spleen FcR positive cells were confined to the periellipsoidal sheaths and the germinal centers. CR positive cells were found in the same spleen areas, as well as in the medulla of bursal follicles. These lymphoid areas reacted strongly with ABS, but they also stained with neutral alpha-naphthyl butyrate esterase, and phagocytosed carbon particles were found in the periellipsoidal sheaths. Furthermore, in vivo treatment with cyclophosphamide, which resulted in pronounced B-lymphocyte depletion, did not affect FcR activity, but reduced CR activity significantly. These data indicate that the FcR activity demonstrated in tissue sections is mainly confined to mononuclear phagocytes, while the CR positive cells are mainly B lymphocytes.

Animals↗
PubMed1982

Predisposition to organ-specific autoimmunity in Obese strain (OS) chickens: reactivity to thyroid, gastric, adrenal and pancreatic cytoplasmic antigens.

In addition to thyroglobulin autoantibodies, some Obese strain (OS) chickens gave organ-specific reactions with the cytoplasm of thyroid acinar cells when the sera were tested by immunofluorescence. The staining pattern was similar to that seen with human antibodies to thyroid microsomes. A proportion stained the proventricular glands of the chicken stomach in a manner indistinguishable from that of pernicious anaemia sera containing parietal cell antibodies. Isolated examples of organ-specific reactions with adrenal and exocrine pancreas were also recorded. These findings strengthen the notion that the OS chicken represents an authentic model for human organ-specific autoimmune disease. The high incidence of non-organ specific reactions complicates but does not necessarily invalidate this view since normal chickens show a propensity to develop such antibodies. However the OS chicken appears to differ from the human in being hyper-responsive to antigens in general.

Adrenal Glands↗
PubMed1981

In vivo studies on prolactin function in the female rat: divergent effects of treatment with bromergocryptine and antisera to rat prolactin.

The effect of suppression of prolactin (PRL) serum levels on early pregnancy and lactation in the rat by means of either bromergocryptine (BEC) or rabbit antiserum to rat PRL has been examined. BEC terminated early pregnancy when given on any day from 1 to 6 and significantly impaired lactation performance when injected during the lactation period. Antibodies against rat PRI, however, showed no effect on either early pregnancy or lactation, although the sera of the treated rats contained free PRL antibodies as evidence for sufficient dosage of antiserum. This finding can be explained in two ways: either the antibodies are not able to neutralize the biological activity of the bound PRL, or the effect of BEC is not mediated by PRL-suppression alone but requires a second component not provided by the specific antiserum.

Animals↗
PubMed1981

Production and characterization of monoclonal antibodies against bovine luteinizing hormone.

Five mouse hybridoma cell lines producing monoclonal antibody against bovine luteinizing hormone (LH) have been established and the respective antibodies characterized by radioimmunoassay, immunofluorescence and immunoelectrophoresis. All antibodies belong to the IgG class and bind to staphylococcus protein A. Intraspecies cross-reactivity studies revealed no reaction with bovine follicle stimulating hormone (FSH). However, all antibodies showed partial cross-reaction with bovine thyroid stimulating hormone (TSH) suggesting a close conformational similarity between bovine LH and TSH. Studies on interspecies cross-reactivity (rat and human) showed that three of these five antibodies strongly react with rat LH but not at all with either rat FSH or rat TSH thus representing monospecific reagents for investigations concerning LH in this species. One of these three antibodies also strongly binds to human LH and to the same extent to human chorionic gonadotropin (CG) but not to human FSH or TSH. It was concluded that at least three different epitopes on the bovine LH molecule are recognized and that they are located on the beta-chain of the hormone.

Animals↗
PubMed1981

Immunological characterization of the 7-S domain of type IV collagens.

Antisera were raised against the long and short form of mouse and human 7-S collagen and against type IV collagens solubilized by acid extraction or limited digestion with pepsin. All the antisera showed strong binding for 7-S collagen in radioimmunoassays demonstrating that the 7-S domain which serves as a cross-linking region of type IV collagen is the most immunogenic portion of the molecule. Cross-reaction studies and analysis of fragments showed a complex antigenic structure including some determinants common to the long and short form of 7-S collagen and others unique for the long form. Purified antibodies against 7-S collagen reacted in indirect immunofluorescence with almost all basement membranes of the body indicating that the 7-S domain is a common structural element of type IV collagens.

Animals↗
PubMed1981

Localization of IgGFc and complement receptors in chicken lymphoid tissue.

Chicken lymphoid organs were examined for IgGFc and complement receptors (FcR/CR) by immune adherence on frozen tissue sections. Indicator systems were sheep erythrocytes (E) coated with chicken anti-E IgG (EAch), E coated with rabbit anti-E IgG (EArab) and normal chicken serum (EAC), and FITC-labelled zymosan particles coated with chicken serum (ZyC). In the spleen, FcR and CR activity was confined to B-dependent areas, i.e. the periellipsoidal sheaths and germinal centres and the red pulp. No FcR were found in the thymic or bursal lymphoid tissue, but CR activity was observed in the medulla of bursal follicles. Chicken and turkey IgG, chicken IgGFc, and bovine serum albumin (BSA)--chicken anti-BSA complexes inhibited binding of Each. No inhibition was obtained with chicken IgGF(ab')2, IgM or albumin, or with BSA--rabbit anti-BSA complexes and human or rabbit IgG. E did not adhere to the sections, nor did EArab, EArab incubated with heat-inactivated chicken serum, or EAC complexes prepared with EArab and guinea-pig complement. The data suggest that chicken B lymphocytes and macrophages have receptors for avian IgGFc and C which can be demonstrated in tissue sections.

Animals↗
PubMed1981

Chicken major histocompatibility complex and disease.

The chicken MHC (B complex) initially described by Briles as controlling blood antigens, is now known to be composed of at least three regions, L, F and G. Two of these, F and G, were described on the basis of recombinants found in a study of over 10,000 chickens. On the basis of biochemical, tissue distribution and functional analyses, F corresponds to the murine H-2 K/D regions. The G region is unique to the chicken since the antigenic product is expressed only on erythrocytes and their progenitors. L was identified by serological studies and corresponds to the H-2 I region; the L antigen is expressed predominantly on B lymphocytes, monocytes and 10% of T lymphocytes, and differences in the L region result in variations in immune responsiveness. A number of functional similarities exist between the chicken MHC and that of other species such as regulation of graft rejection, graft-versus-host reaction (GVHR) and mixed lymphocyte reactions (MLR), mitogenic and immune responsiveness and resistance to RNA and DNA virus infection. The chicken MHC also controls the severity of autoimmune disease, as exemplified by the spontaneous thyroiditis of Obese strain (OS) chickens. It differs from mammalian MHC's by having of lower crossing-over frequency and no apparent gene duplication.

Animals↗
PubMed1981

Requirement of T cells for the development of spontaneous autoimmune thyroiditis in obese strain (OS) chickens.

A combination of neonatal thymectomy and intensive treatment with a highly specific turkey anti-chicken T cell serum effectively abrogates the spontaneous development of thyroiditis and thyroglobulin autoantibodies in the Obese strain chicken. Thus, in addition to a restraining influence of suppressor T cells on the disease process indicated by earlier studies, it would appear that T cells also make a positive contribution to pathogenesis.

Animals↗
PubMed1980

[Timing of ovulation in clomiphene-induced cycles (author's transl)].

214 menstrual cycles, induced by clomiphene in 121 women desiring a family but manifesting disturbances of cycle, type WHO II (1976) were investigated with regard to pattern of cervical function. 184 were ovulatory cycles. The time of ovulation was predictable within a range of two days in 58.7% of cases by means of the cervical score, consisting of the dilatation of the cervical os, the degree of transparency, the quantity and the consistency of the cervical mucus. The occurence of the "LH peak" and the rise in basal body temperature (BBT) were set in relation to this. In 41.3% of cycles the cervical score, influenced by the antioestrogenic effect of clomiphene, gave only insufficient evidence. In subsequent treatment cycles the cervical function, in relation to the individual case and the inducible quality of the cycle, showed a similar response rate as in the first treatment cycle. Our results suggest that, after examination of the first clomiphene-induced cycle by the combined means of cervical score and hormoneanalytic methods, patients with a positive cervical response, can be investigated by any interested doctor, even if he doesn't have a laboratory at his disposal, in order to assess the timing of ovulation for therapeutic measures.

Body Temperature↗
PubMed1980

Killer cells in the chicken: a microcytotoxicity assay using antigen-coated erythrocytes as targets.

A 51chromium (51Cr)release microcytotoxicity assay has been established for studying cell-mediated immunity in chickens to a potentially wide variety of antigens. The system investigated in detail uses thyroglobulin-coated chicken red blood cells (Tg-CRBC) to analyse effector cell mechanisms operative in spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. A variety of technical parameters were investigated in order to optimise reliable, reproducible target cell preparation and to minimise spontaneous 51Cr-release. The final method adopted used tannic acid for coupling antigen to carefully selected donor erythrocytes of uniform MHC genotype. For the study of antibody dependent, cell-mediated cytotoxicity, Tg-CRBC were pre-sensitised with OS serum containing high titre Tg-autoantibody. Tannic acid-treated CRBC (TA-CRBC) served simultaneously as controls for the Tg specificity of direct cellular cytotoxicity (DCC) to Tg-CRBC, and also as target cells for natural, or spontaneous cellular cytotoxicity (SCC). With such an assay, cells capable of mediating Tg-specific DCC were demonstrated in the OS, but not in normal chickens. No differences in ADCC or SCC were observed when the two strains were considered as a whole, i.e. regardless of age, sex, MHC genotype or extent of disease.

Animals↗