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Studies the delineation of different antigenic surface determinants on the surface of adult peripheral T cells by means of a specific horse anti-human T-cell serum. Evidence showing the presence of a close steric relationship between E receptors and T antigens; Evidence showing that the E receptor and T antigens are separately mobile within the T-cell membrane.

Appropriately absorbed turkey antisera to antigenic surface determinants of chicken bursa (ABS) or thymus cells (ATS) were assessed for their selective immunosuppresive activity in vitro and in vivo. The intraperitoneal injection of ABS or ATS in 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 in skin allografts from donors of genotype B4B4 onto B8B8 recipients was significantly prolonged by treatment with ATS (29 ± 12 days) as compared to untreated (14 ± 2 days), normal turkey serum (12 ± 3 days) or ABS-injected (13 ± 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. [ABSTRACT FROM AUTHOR]

Basement membrane (type IV) collagens were extracted from a mouse tumour with acetic acid and from human placenta after limited enzymatic digestion. Antisera were produced against both collagens in rabbits and guinea-pigs and examined by various assays. These antisera were found to be specific for basement membrane collagen and showed little or no cross-reactions with the interstitial collagens, types I, II and III or with human placenta collagen consisting of αA and αB chains. Varying degrees of cross-reaction were observed between antisera to human and mouse type IV collagen. Immunochemical analyses demonstrated the presence of three distinct determinants in the tumour type IV collagen. Rabbit antisera against this antigen reacted with either collagenase-resistant segments or with a collagenous, disulphide-bonded segment (P3). Guinea-pig antisera recognized primarily antigenic determinants in the P3 segment. Antisera to placenta type IV collagen reacted with another collagenous, pepsin fragment (P1) which lacks disulphide bonds. These antisera showed complete cross-reaction with collagenous αI(IV) chains prepared from pepsin-digests of human placenta and bovine lens capsule. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 front fish as compared with avian red cell nuclei. Absorption of chicken sera with eryhrocyte 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. [ABSTRACT FROM AUTHOR]

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 APFreactivity 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 irnmunofluorescence 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Antibodies against basement zone in the sera of two patients with bullous pemphigoid were studied by indirect immunofluorescence. Monkey and guinea-pig lip and oesophagus were used as antigen and the effects were observed of using various concentrations of the human serum and the fluorescein-labelled goat anti-hun-tan IgG conjugate. The plateau titre of the human serum depends upon the fluorescein/protein ratio of the conjugate. The highest dilution of conjugate giving this plateau titre is called the plateau endpoint and depends upon the amount of antibody in the conjugate, i.e. the unitage of the conjugate. A serum with a high titre of antibody gave similar results with monkey and guinea-pig tissues but a serum with a low titre gave variations in the plateau titre and plateau endpoint even when tissue from only one species was used. It was concluded that quantitative differences exist in the antigenic strength of basement membranes of different tissues even within one species. Guinea-pig lip appears to be suitable for diagnosis of bullous pemphigoid. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

CR2, the receptor for the C3d fragment of the third complement component and for Epstein-Barr virus (EBV) has been shown, on mouse B cells, to be involved in the control of B-cell proliferation by acting as a receptor for macrophage-derived growth factors. We examined whether the growth of a Burkitt lymphoma cell line, RAJI, could be influenced by ligands of human CR2. In serum-free culture, purified human C3d, as well as three monoclonal antibodies to distinct epitopes on human CR2, were capable of enhancing the growth rate of RAJI cells two to five-fold. This effect could not be observed if even trace amounts of serum were present in the culture medium. Simultaneous addition of pairs of antibodies did not enhance the growth rate, suggesting that a particular engagement of CR2 may be critical in order to induce a stimulatory effect. These results indicate that in a homologous serum-free human B-cell system human C3d as well as monoclonal antibodies to human CR2 can induce B-cell proliferation and that CR2-mediated triggering of B cells can be induced via epitopes other than the C3d-binding site. In addition we conclude that--unlike normal human B cells--at least some human B-lymphoma cells respond to CR2-mediated stimuli in the absence of any T-cell derived factors. Therefore the control mechanisms exerted through CR2 must still be intact on these autonomously growing cells.