Biomedical subjects

G Wick

Publications and source records attributed to G Wick.

At least 379 records · Page 21Linked to original sources

PubMed1975

The nature of active and passive thyroglobulin binding lymphoid cells in Obese strain (OS) chickens.

Thyroglobulin-binding lymphoid cells were identified in the spleen of Obese strain (DS) chickens by their capacity to form rosettes with thyroglobulin-coated chicken red blood cells. The nature of these cells was studied in inhibition experiments using turkey anti-chicken bursa or thymus cell sera and rabbit antisera specific for chicken Ig, gamma, mu, alpha, Fabgamma or Fcgamma. Spleen cells actively synthesizing surface receptors for thyroglobulin were identified as B cells and the receptors found to be complete IgM molecules. Normal T cells became thyroglobulin-rosette-forming cells via passive adsorption of thyroglobulin antibodies, a phenomenon which could be inhibited competitively by the addition of normal chicken serum to the incubation medium. Thyroglobulin antibodies passively adsorbed onto the surface of normal T cells also belong to the IgM class as verified both by inhibition experiments and studies employing IgM and IgG fractions of a high titered OS serum for the preincubation of the cell suspensions. Only preincubation with the IgM fraction of the anti-thyroglobulin antibodies resulted in the formation of significant numbers of passive rosette-forming cells.

Animals↗

PubMed1975

Investigation of the recovery phenomenon in immunofluorescence after laser excitation.

Laser excitation was applied in two standard immunopathological indirect immunoflorescence systems in order to investigate bleaching and recovery of fluorescence intensity upon repeated illuminations. Variation of illumination times and dark periods between these showed that the recovery phenomenon is a function of both the (time times energy) product of excitation and the length of dark intervals. The value of high energy excitation in immunofluorescence in providing insight into the mechanisms of bleaching and recovery is discussed.

Antibodies, Antinuclear↗

PubMed1975

Purified antibodies to collagen: an immunofluorescence study of their reaction with tissue collagen.

Antibodies to soluble calf or rat skin collagen were purified by appropriate immunoadsorption and separated into three subfractions directed either to antigenic sites on unfolded alpha-chains (denatured collagen), to nonhelical sites, or to helical sites exposed on the triple helical molecule. In indirect immunofluorescence tests each of the antibody solutions reacted with collagen of skin and kidney tissue, although the latter two antibody solutions appeared to be more active. Distinct activity was also observed with antibodies to the N-terminal antigenic determinant of rat skin collagen alpha2-chain, a structure usually involved in cross-linking. Indirect immunofluorescence tests with anti-collagen sera on sections of skin resulted in the staining of the whole dermis, while anti-procollagen sera revealed binding only to the uppermost subepithelial layer of the dermis (stratum papillare). On kidney sections only the interstitial connective tissue reacted with purified anti-collagen or anti-procollagen sera. Both skin and glomerular basement membranes remained unstained with either kind of purified antibodies. However, antisera not subjected to immunoadsorption do react with the glomerular basement membrane. Antibodies to noncollagenous contaminants are considered to be responsible for this finding which emphasizes the necessity to use purified antibodies exclusively for this type of immunofluorescence analysis.

Adsorption↗

PubMed1975

Heteroagglutinins and spontaneous rosette-forming cells in obese strain (OS) chickens.

Sera of OS chickens with spontaneous autoimmune thyroiditis (SAT) and of normal white Leghorn (NWL) controls, aged 4-20 weeks, were studied for the presence of heteroagglutinins to sheep (SRBC) and rabbit red blood cells (RRBC). Significantly higher frequency and titers of SRBC- and RRBC-agglutinins were found in OS as compared to NWL birds, the difference being more accentuated with RRBC. The number of spontaneously rosette-forming peripheral blood lymphocytes (RFC) with SRBC and RRBC was determined in 20-week-old OS and NWL chickens. The number of RRBC-RFC was found to be significantly elevated in the OS. The value of RFC did not correlate with the individual heteroagglutinin titers. RFC and heteroagglutinin secreting cells are considered to be nonidentical. These results are discussed in the light of the previously established hyperreactivity of the B-dependent portion of the immune system in OS chickens.

Animals↗

PubMed1975

Thyroglobulin-binding lymphoid cells in obese strain (OS) chickens.

The binding of chicken thyroglobulin-coated chicken red blood cells by splenic, thymic, and bursal lymphoid cells was analysed in Obese strain (OS) chickens with spontaneous autoimmune thyroiditis and normal white Leghorn controls aged 1 week to 2.5 yr. Chicken erythrocytes coated with pneumococcal polysaccharide SIIII served as controls. The specificity of thyroglobulin-rosette-forming cells was verified by inhibition experiments. OS chickens showed significantly higher counts of thyroglobulin-rosette-forming cells in the spleen and thymus as compared to normal controls while no such difference was found for SII-rosette-forming cells. The values obtained with bursal lymphoid cells were in the same range in both OS and normal white Leghorn birds. The appearance of thyroglobulin-rosette-forming cells and their peak values clearly preceded the maximum frequency and severity of thyroiditis and the peak of the thyroglobulin antibody curve. It is concluded that the presence of thyroglobulin rosette-forming cells is a prerequisite for the future development of spontaneous autoimmune thyroiditis in the OS. Inhibition studies with specific turkey anti-chicken bursa and thymus cell sera revealed the B cell nature of active thyroglobulin-rosette-forming cells and suggested that passive rosette-forming cells were of T cell origin.

Animals↗

PubMed1975

Antigenic surface determinants of chicken lymphoid cells. II. Selective in vivo and in vitro activity of anti-bursa and anti-thymus sera.

Appropriately absorbed turkey antisera to antigenic surface determinants of chicken bursa (ABS) or thymus cells (ATS) were assessed for their selective immunosuppressive activy in vitro and in vivo. The intraperitoneal injection of ABS or ATS into 2-3-week-old normal white Leghorn chickens entailed a significant depletion of B or T cells respectively from spleen and peripheral blood, while bursa and thymus themselves remained unaffected. The potential of this 'peripheral serological bursectomy and thymectomy' paralleled that found after the conventional surgical procedures with subsequent sublethal irradiation. The mean survival time of skin allografts from donors of genotype B4B4 onto B8B8 recipients was significantly prolonged by treatment with ATS (29 plus or minus 12 days) as compared to untreated (14 plus or minus 2 days), normal turkey serum (12 plus or minus 3 days) or ABS-injected (13 plus or minus 2 days) groups. This selective suppression of a T cell-dependent immune reaction by ATS was also confirmed in vitro by its inhibitory action on the graft-versus-host reactivity of adult peripheral blood lymphocytes in the chorioallantoic membrane assay, where normal turkey serum and ABS were again ineffective. Thus, ABS or ATS produced in avian species may serve not only to delineate B and T cells in vitro, but can also be used for selective manipulation of immune reactions of the chicken in vivo.

Animals↗

PubMed1974