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.

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.

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.

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 SIII 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 SIII-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 thyroditis 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.

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.

Increased 131I uptake by the thyroid glands of Obese strain (OS) chickens derived from non-Protamone-supplemented hens

The Obese strain (OS) of chickens spontaneously develops autoimmune thyroiditis several weeks after hatching, characterized by severe lymphoid infiltration and circulating thyroglobulin antibody. Sundick & Wick (1974) found that the thyroid glands of OS embryos and newly hatched chicks actually incorporated more ¹³¹I than normal controls when the parents of both groups were fed a Protamone-supplemented diet. Since this material—an iodinated casein containing thyro-active substances—drastically reduced thyroidal uptake of ¹³¹I, several experiments were designed to compare OS and normal chicks free from these effects. In the first experiment the dietary supplementation of OS and normal hens were changed from Protamone to pure thyroxine and triiodothyronine. Their eggs were collected daily and incubated. The hatched chicks were tested for 20-hr ¹³¹I uptake and it was determined that 11–18 days after the food switch, the inhibition of uptake by Protamone was reversed, and the newly hatched OS chicks still had a significantly increased 20-hr ¹³¹I uptake when compared to the normal controls. Comparison of the offspring of a special flock of OS hens that lays without hormonal supplementation, with the parental Cornell C strain from which the OS is derived, similarly revealed a higher 20-hr ¹³¹I uptake by the OS (P<0·005). The increased thyroidal uptake of OS was apparent as early as 4 hr after ¹³¹I administration and seemed to be independent of slight variations in the amount of ¹²⁷I available to the chicks, and also seemed to be independent of maternally derived thyroglobulin antibody vertically transferred into OS chicks.

These results suggest that an abnormality of the OS thyroid gland might be a prerequisite for the spontaneously occurring autoimmune thyroiditis in this strain.

Local production of immunoglobulin in the thyroid gland of obese strain (OS) chickens

Thyroid glands of Obese strain (OS) chickens with spontaneous hereditary autoimmune thyroiditis were studied by direct immunofluorescence (DIF) with an anti-chicken immunoglobulin–FITC conjugate for local immunoglobulin (Ig) production in plasma cells and germinal centres. Many plasma cells and most of the germinal centres showed positive staining in DIF. The Ig property of this stained material was verified by DIF blocking and indirect immunofluorescence (IIF) tests with specific unlabelled anti-chicken Ig sera. In a chronological DIF study of thyroid glands from OS chickens aged 1–18 weeks, Ig-producing plasma cells could be already detected in the 1st week of life. DIF tests with TRITC-labelled chicken thyroglobulin revealed positive staining of plasma cells with preferential localization in close proximity to, or even between, follicular epithelial cells, suggesting the anti-thyroglobulin autoantibody nature of at least some of the locally produced Ig.

Positive results in DIF and IIF tests performed on infiltrated thyroid glands of OS chickens immunized with bovine serum albumin indicated the capacity of many infiltrating lymphoid cells within the thyroid to respond to exogenous antigens too.

Immunoglobulin production in chicken Harderian glands

The Harderian gland of chickens is known to become infiltrated by plasmacytoid cells 2–4 weeks after hatching. Most of these cells carry immunoglobulin surface determinants (ISD). By indirect immunofluorescence procedures and using heavy-chain-specific antisera to chicken IgM, IgG and IgA, it was possible to delineate the percentage of cells with surface determinants of different immunoglobulin classes. It was found that up to the fourth week after hatching, most of the cells bear IgM as ISD. From the fourth to the ninth week, both IgG- and IgA-positive cells form the bulk of the lymphoid cell population, whereas later on, IgA alone was the predominant specificity of ISD. Cytoplasmatic staining of fixed cells revealed a similar pattern of immunoglobulin class distribution, the IgA-producing cells forming clusters within the stroma of the Harderian gland along and around the excretory ducts. IgG-producing cells were also encountered in groups in the interepithelial regions, but IgM-positive cells occurred singly. IgA was also detected in the cytoplasm of epithelial cells, mostly in the supranuclear portion.

Antigenic surface determinants of chicken lymphoid cells. I. Serologic properties of anti-bursa and anti-thymus sera

The serologic properties of turkey antisera to chicken bursa (ABS) and thymus (ATS) cells were assayed by cytolysis-in-agar, conventional cytotoxicity tests and indirect immunofluorescence. Using proper absorptions the following antigenic surface determinants were detected on bursal and thymic lymphoid cells: (a) common lymphocyte antigens present on both kinds of cells; (b) thymus-specific antigens; (c) bursa-specific antigens; (d) in addition to the latter, bursa cells displayed immunoglobulin surface determinants. Even before absorption the anti-thymus and anti-bursa sera gave higher titres of reactions with homologous target cell preparations. In complement dependent cytotoxicity tests ABS and ATS reacted specifically with bursa and thymus cells respectively. In the spleen of 2- and 3-week-old chickens 20–30% of lymphoid cells were killed by ABS and 40–50% by ATS. The advantage of avian antilymphocyte sera for in vivo studies in chickens are emphasized.

The influence of thymectomy on the development of erythrocyte-specific antinuclear factors in obese strain (OS) and normal white leghorn chickens

In addition to spontaneous autoimmune thyroiditis, chickens of the Obese strain (OS) develop a high incidence of erythrocyte-specific antinuclear factors (EANF). Normal White Leghorn (NWL) chickens also display EANF, although in low frequency and titre. Neonatal thymectomy leads to an increase in both frequency and titre of EANF in OS and NWL birds. While thymectomized OS chickens show the highest titres, those of thymectomized NWL birds are in the same range as in untreated OS chickens. In ovo bursectomy suppresses the development of EANF.

Immunoglobulin determinants on the surface of chicken lymphoid cells

The percentage of lymphoid cells carrying immunoglobulin surface determinants was examined for the yolk sac, bursa of Fabricius, thymus, bone marrow, blood lymphocytes, spleen, cecal tonsils and Harder’s glands in normal White Leghorn chickens from the 11th day of incubation until the 26th week after hatching, using direct immunofluorescent staining with a fluoresceinated rabbit anti-chicken immunoglobulin serum. The results clearly show that under the test conditions employed surface immunoglobulins are markers of a bursa cell population or of bursa-derived cells, whereas thymus cells react only minimally with anti-immunoglobulin conjugates in young chickens. The migration pattern and maturation of bursa cells were studied chronologically as reflected in appearance, quantity and morphology of immunoglobulin surface determinant bearing cells in different organs.

Serum lipid pattern in chickens of the obese strain

Blood sugar, the serum concentration of total lipids, total glycerol, cholesterol and phosphatides were determined in chickens from the Obese strain (OS) of White Leghorns. Over 90% of these chickens are afflicted with a spontaneously occurring autoimmune thyroiditis and show clinical symptoms of hypothyroidism. Blood glucose levels were increased above normal limits in OS chickens up to 5 weeks of age. Significantly increased serum lipid concentrations were found in the OS chickens at the ages of 1, 5, 8 and 15 weeks, while 3-week-old OS chickens showed almost normal serum lipid levels. A single intravenous injection of heparin in a dose which prolonged bleeding time, had no 'clearing effect' on the serum of OS birds. Insulin given subcutaneously for 4 days had no effect on blood sugar but decreased the serum phosphatides and total lipid concentrations. The short-term administration of high doses of thyroxine significantly lowered the serum levels of total lipids, cholesterol, phosphatides and total glycerol.

Photometric evaluation of indirect immunofluorescence chessboard titrations for the characterization of FITC-labelled antibodies

The immunofluorescent staining properties of three FITC-labelled anti-human IgG rabbit globulin preparations with very similar antibody concentration (595, 570 and 565 μg/ml), but different molar fluorescein/protein ratios (4.2, 1.4 and 0.7) were compared by means of indirect immunofluorescence chessboard titrations. A selected serum from a patient with systemic lupus erythematosus containing antinuclear factors was tested on formalinized chicken red blood cells using incident light illumination. Both visual and photometric readings were taken. The characteristic pattern of chessboard titrations with a constant titre (plateau titre) over a wide range of conjugate dilutions followed by an abrupt fall (plateau end-point) was obtained and showed good correlation by both methods of evaluation. The height of the plateau titre increased with increasing fluorescein/protein ratio, but no linear relationship could be established with the three conjugates under investigation. The plateau end-point was encountered at conjugate dilutions containing similar antibody concentrations namely 9.3, 8.9 and 8.8 μg/ml. From the good correlation between photometric and visual readings it is concluded that chessboard titrations provide an objectively-acceptable method for the evaluation of fluorescent conjugates and adoption of the procedure by manufacturers of conjugates is suggested.

Demonstration of thyroglobulin in the thyroid glands of obese strain and normal white leghorn chicken embryos

The earliest detectable presence of thyroglobulin has been measured in Obese Strain and normal White Leghorn chicken embryos of different ages by means of indirect immunofluorescent staining, double diffusion in gel, and haemagglutination-inhibition. Thyroglobulin could be demonstrated as early as the ninth day of incubation of OS or normal eggs. No antigenic differences could be demonstrated between thyroglobulin from OS and normal chickens or between thyroglobulin from embryos and from adult chickens. The implications of these findings for the pathogenesis of the autoimmune thyroiditis developed in the OS chickens are discussed.

Erythrocyte-specific anti-nuclear factors in chickens of the obese strain (OS)

By indirect immunofluorescence the sera of OS chickens were shown to contain anti-nuclear factor(s) (ANF) in high frequency and at titres up to 320. Normal White Leghorn (NWL) chickens also had circulating ANF, but in low percentage and in titres up to 40 only. Neonatal OS chickens lacked demonstrable ANF. Chicken ANF could be demonstrated only if nuclei of red blood cells from birds or fish were used as antigenic substrate, but not chicken leucocytes or cryostat sections of chicken, rat or guinea-pig liver, or sections of chicken or bovine thymus. Reactivity was equal on homologous and autologous red cell nuclei. Lower titres were observed with nuclei from fish as compared with avian red cell nuclei. Absorption of chicken sera with erythrocyte nuclei of different species resulted in removal of ANF in accordance with previously established reactivity with these nuclei. In reciprocal indirect immunofluorescence blocking tests with a human SLE serum a unidirectional inhibition of chicken ANF was observed. The findings suggest that chicken ANF may be directed against a serine-rich histone fraction unique for red cell nuclei. Preliminary studies of the sera of neonatally thymectomized OS chickens revealed a significant increase in frequency and titres of erythrocyte-specific ANF by comparison with untreated birds of this strain. This supports the hypothesis that the intact thymus exerts a control function over the immunological self-recognition mechanism.

Immunofluorescent studies of thyroid auto-antibodies in chickens of the obese strain (OS)

Chickens of the Obese strain (OS) exhibit a hereditary, spontaneous auto-immune thyroiditis. Thyroglobulin auto-antibodies have so far been demonstrated by passive haemagglutination and precipitation. A standardized indirect immunofluorescent staining system has been established as an additional technique for the demonstration of these antibodies. Two kinds of circulating thyroglobulin antibodies were found in OS chickens, one demonstrable by passive haemagglutination only, the other by both precipitation and indirect immunofluorescence using a fluorescein isothiocyanate conjugate directed predominantly against chicken IgG. Results obtained in chessboard type indirect immunofluorescence blocking tests and with column chromatographic fractions of OS sera are suggestive that the haemagglutinating kind of thyroglobulin antibodies are of the IgM class, while the antibodies reactive in precipitation and indirect immunofluorescence are of IgG type. The autoantibody nature of the thyroglobulin antibodies in OS chickens was demonstrated by indirect and direct immunofluorescent staining of autologous thyroid sections. With the immunofluorescence techniques employed so far, antibodies directed against antigenic components of the thyroid epithelium of OS chickens have not been demonstrated.

The effect of bursectomy, thymectomy and x-irradiation on the incidence of precipitating liver and kidney auto-antibodies in chickens of the obese strain (OS)

The Obese strain of White Leghorn chickens is afflicted with a spontaneously occurring autoimmune thyroiditis. Thyroglobulin auto-antibodies predominate in the sera of Obese strain chickens, but precipitating auto-antibodies against components of other organs—mainly liver and kidney—also occur in a low percentage, either in combination with or in the absence of thyroglobulin antibodies. Surgical bursectomy in ovo or on the day of hatching completely prevents the formation of precipitating non-thyroid antibodies in the Obese strain chickens. On the other hand, neonatal thymectomy results in a significant increase in the incidence of liver and kidney antibodies in Obese strain, and even in normal White Leghorn chickens. Thymo-bursectomy on the day of hatching has an effect similar to that of bursectomy alone, i.e. prevents the appearance of liver and kidney antibodies. Neonatal, sublethal total body X-irradiation also leads to a slightly lower frequency of liver and kidney antibodies in Obese strain chickens. A possible control function of the intact thymus over the self-recognition mechanism is discussed.

Quantitative studies of immunofluorescent staining. IV. Indirect immunofluorescence blocking tests with anti-perinuclear factors of human and goat origin

The antiperinuclear factor (APF) is found in a high percentage of sera from patients with rheumatoid arthritis. It can be demonstrated by direct immunofluorescence using the keratohyaline granules of human buccal mucosa as antigenic substrate. Mixing of some normal goat sera with an APF positive serum from a patient with rheumatoid arthritis resulted in an inhibition of the APF titre of the patient's serum. However, there was no clear cut correlation between the APF-positivity of normal goat sera and their inhibitory effect on the APF-reactivity of a human rheumatoid arthritis patient's serum. In reciprocal screening tests the human rheumatoid arthritis serum blocked only one of the APF-reactive goat sera. The reciprocal blocking activity of this goat serum and the patient's serum could be more exactly evaluated by the use of chessboard titrations in an indirect immunofluorescence blocking test. This test consisted of mixing equal volumes of serial dilutions of a goat serum and the patient's serum and subsequent examination of the mixtures for APF using an anti-human IgG conjugate and an anti-goat immunoglobulin conjugate, respectively. The results point to an antibody nature for the APF in preimmune, normal goat sera and to the value of chessboard titrations of this type in demonstrating the identity, non-identity, partial identity (or very close proximity of antigenic determinants) of the antibodies in different antisera which cannot be distinguished by their immunofluorescent staining patterns.

Immunogenicity and specificity of collagen. 8. Studies on the antigenic structure of soluble fish collagen

In rabbit antisera to acid-soluble carp collagen two antibody fractions differing in specificity were demonstrated by passive haemagglutination. The antibody fractions were separable from each other on an immunoadsorbent prepared from rabbit collagen. One reacted exclusively with carp collagen, the other reacted additionally with various mammalian collagens including that from rabbit. The results were interpreted as evidence for the presence of at least two different antigenic determinants on carp collagen resembling former results for calf collagen.