Inhibition of the development of spontaneous autoimmune thyroiditis in the obese strain (OS) chickens by in vivo treatment with anti-CD4 or anti-CD8 antibodies.

The involvement of CD4+ and CD8+ T cells in pathogenesis of spontaneous autoimmune thyroiditis (SAT) in obese strain (OS) chickens has not been studied in depth until now. We depleted CD4+ or CD8+ T cells in OS chickens by treatment with murine monoclonal anti-CD4 or anti-CD8 antibodies at 3 day intervals beginning at hatching. The birds were killed at 19-25 days of age.

Preclinical evaluation of biotin labeling for red cell survival testing.

Biotin labeling of red cells was tested in dogs as a preclinical study for cell survival. Red cells were labeled with either spacered Biotin-X-NHS (BxNHS) or water-soluble biotin compounds. After reinfusion, biotinylated red cells were detected in small blood samples (5 microliters) with flow cytometry.

Comparison of T-cell subpopulations in cats naturally infected with feline leukaemia virus or feline immunodeficiency virus.

T-cell subsets were studied by flow cytometry in 58 feline leukaemia virus (FeLV)-positive cats with naturally acquired FeLV infection to determine whether the changes in CD4+ or CD8+ T cell populations differed from those observed in 55 feline immunodeficiency virus (FIV)-positive cats with naturally acquired FIV infection. The sole criterion for inclusion into the study was seropositivity. Mean (SD) CD4+ T cell values of FeLV positive cats were decreased to 31.

Prevention of spontaneous autoimmune thyroiditis in the obese strain (OS) chickens by treatment with a monoclonal anti-CD4 antibody.

Untreated control OS chickens develop spontaneous autoimmune thyroiditis (SAT). In contrast, OS chickens treated with a monoclonal anti-CD4 antibody failed to develop SAT. The preventive effect of anti-CD4 antibody on SAT was associated with the marked depletion of CD4+ T-cells by anti-CD4 treatment.

Peripheral blood leukocyte grafts that induce human to mouse graft-vs.-host disease reject allogeneic human skin grafts.

Allogeneic graft-versus-host disease is characterized by skin, gut, and bile duct destruction by relatively few donor type lymphocytes. In contrast, we can now show that human-to-mouse xenogeneic graft-versus-host disease is characterized by vasculitis and tumor-like infiltrations of the murine lymphohemopoietic organs with many human CD25+, HLA-DR+, CD4+ lymphoblasts. Using the technique of serial transplantation, it appears that at least 90% of the human lymphoblasts were unreactive to murine tissues.

Suppression of normal and neoplastic human T cells with unconjugated monoclonal antibodies in SCID mouse chimeras.

The aim of this study was to establish a preclinical in vivo model to evaluate the suppressive effect of unconjugated anti-human T (CD3, 5, 7)-cell monoclonal antibodies (mAb) of mouse IgG2a or rat IgG2b isotype. Therefore, severe combined immunodeficient (SCID) mice were transplanted with human peripheral blood lymphocytes (PBL) of healthy donors (hu-PBL-SCID) or with neoplastic T cells of the human T-ALL cell line Jurkat. In preselected hu-PBL-SCID mice with substantial T cell chimerism single antibody injection caused prompt suppression of circulating human T lymphocytes within 2 days followed by occasional T cell recovery during the following weeks.

Preferential TCR V beta 1 gene usage by autoreactive T cells in spontaneous autoimmune thyroiditis of the obese strain of chickens.

We studied T cell receptor variable beta (TCR V beta) gene usage by autoreactive T cells in spontaneous autoimmune thyroiditis (SAT) of obese strain (OS) chickens. Chicken alpha beta T cells may express either V beta 1 or V beta 2 genes, the products of which can be recognized by TCR2 and TCR3 monoclonal antibodies, respectively. Selective depletion of V beta 1+ or V beta 2+ T cells in OS chickens was accomplished by repeated injections of TCR2 or TCR3 antibodies into embryonic and 1-3-week-old chickens.

Rat monoclonal antibodies differentiating between the Epstein-Barr virus nuclear antigens 2A (EBNA2A) and 2B (EBNA2B).

Rat monoclonal antibodies were produced against the C-terminus of Epstein-Barr virus nuclear antigens 2A (EBNA2A) and 2B (EBNA2B) expressed as bacterial trpE fusion proteins. The initial screening was performed using a soluble bacterial extract containing the fusion proteins. Positive hybridomas were confirmed by immunofluorescence on SF158 (Spodoptera frugiperda) insect cells infected with recombinant baculovirus (Autographa californica nuclear polyhedrosis virus) and expressing the complete EBNA2A or EBNA2B genes.

A mouse model for the preclinical evaluation of immunosuppressive effector functions of human isotypes. The human IgG1 isotype is superior to IgG3.

Antibodies against T cells are widely used as immunosuppressive agents in clinical therapy. As effector functions of chimeric or humanized anti-T cell antibodies cannot be predicted in vitro, we compared T cell-depleting effects of human isotypes in vivo with their immunosuppressive consequences in a mouse BMT model. This system is based on chimeric antibodies with a mouse pan T cell specificity and human constant regions.

Identification and characterization of a mouse monoclonal antibody (M10) directed against canine (dog) CD8+ lymphocytes.

Monoclonal antibodies (mAb) were produced by immunizing BALB/c mice with non-adherent dog lymphocytes. M10 was specific for a subset of dog lymphocytes. M10 belonged to the IgG1 subclass and reacted with 26% of dog peripheral blood lymphocytes, 24% of spleen lymphocytes, 81% of thymus cells, 1.

Biotin labeling as an alternative nonradioactive approach to determination of red cell survival.

Biotin labeling of red cells was studied using different approaches to see if biotinylation is a useful label for determination of erythrocyte survival. Mouse red cells were labeled with biotin, either in vivo by injection or in vitro. In vivo labeled red cells were followed up in some mice without transfusing the labeled erythrocytes.

In vivo depletion of chicken T-cell subsets.

In the chicken three types of T-cell receptors can be defined by monoclonal antibodies TCR1, TCR2 and TCR3, which recognize gamma delta T cells, and V beta 1- and V beta 2-expressing alpha beta T cells, respectively. In the present report we have analysed means of selectively depleting the gamma delta T cells and the V beta 1+ alpha beta T cells. gamma delta T cells, which represent up to 66% of all T cells in blood of a 6-month-old chicken, can be effectively depleted by neonatal thymectomy (Tx) to levels as low as 1%.

Immunohistology and immunocytology of human T-cell chimerism and graft-versus-host disease in SCID mice.

Surprisingly little graft-versus-host disease (GVHD) has been observed in severe combined immunodeficient (SCID) mice injected intraperitoneally (IP) with human blood lymphocytes (hu-PBL-SCID), which raised the question as to whether GVHD in such a distant species is sporadic or suppressed because of immunologic reasons. After screening for blood T-cell chimerism, we hereby describe generalized lethal xenogeneic human GVHD in unconditioned SCID chimeras, which resembles GVHD in SCID mice injected with allogeneic lymphocytes. We adapted an immunocytochemical slide method for minute cell numbers, which allowed us to follow, by multimarker phenotyping of weekly mouse-tail bleeds, the chimeric status of 100 hu-PBL-SCID injected with 10(7) or 10(8) hu-PBL of Epstein-Barr virus- (EBV-) donors.

Use of two virustatica (AZT, PMEA) in the treatment of FIV and of FeLV seropositive cats with clinical symptoms.

In the present study the therapeutic efficacy and the side effects of two antiretroviral compounds used in human acquired immunodeficiency syndrome (AIDS) research, 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine, Retrovir) and 9-(2-phosphonylmethoxyethyl)adenine (PMEA), were investigated in the treatment of cats naturally infected with feline immunodeficiency virus (FIV) and cats naturally infected with feline leukemia virus (FeLV). AZT was administered subcutaneously at a dose of 5 mg kg-1 body weight every 12 h and PMEA was administered subcutaneously at a dose of 2.5 mg kg-1 body weight every 12 h during a 3 week hospitalization.

Peritoneal sanctuary for human lymphopoiesis in SCID mice injected with human peripheral blood lymphocytes from Epstein-Barr virus-negative donors.

The successful engraftment in SCID mice of intraperitoneally (i.p.) injected human lymphocytes (hu-PBL-SCID) and the failure of intravenously injected peripheral blood lymphocytes (PBL) directed the present study to investigate the early events of donor cell proliferation in the peritoneal cavity.

Decline in CD4+ cell numbers in cats with naturally acquired feline immunodeficiency virus infection.

T-cell subsets were studied by fluorescence-activated cell sorter analysis in 57 feline immunodeficiency virus (FIV)-seropositive cats with naturally acquired FIV infection to see whether CD4(+)-CD8+ alterations were comparable to those observed in human immunodeficiency virus-infected patients. CD4+ values were decreased and CD8+ values were increased. The CD4+/CD8+ ratio was reduced to 1.

T cells expressing the V beta 1 T-cell receptor are required for IgA production in the chicken.

While alpha beta T cells in mammals may express one of many variable (V) gene families in the beta locus, chickens have only two V beta gene families. The avian V beta 2+ T cells are recognized by the T-cell receptor 3 (TCR3) monoclonal antibody and V beta 1+ T cells are recognized by the TCR2 antibody, which we used to selectively suppress development of V beta 1+ T cells in order to examine their functional role. Suppression was accomplished by multiple injections of anti-TCR2 antibodies beginning in embryonic life and perpetuated by thymectomy 8 days after hatching.

[T-helper and T-suppressor lymphocyte subpopulations in the peripheral blood of spontaneously FIV-positive cats].

Reduced CD4(+)-T-helper-lymphocyte- and increased CD8(+)-T-suppressor-lymphocyte-subsets were found in peripheral blood of 47 FIV-seropositive cats with naturally acquired FIV-infection. The CD4+/CD8+ ratio was decreased, too. Variance analysis of data included the variables reaction in FIV-test, age group, and race.

Direct in vivo biotinylation of erythrocytes as an assay for red cell survival studies.

Direct in vivo labeling of erythrocytes with biotin is shown as a method for estimation of red cell survival as well as of enrichment of young or aged erythrocytes. Two succinimide esters (biotin-N-hydroxysuccinimide ester [BNHS], caproylamidobiotin-N-hydroxysuccinimide ester [C-BNHS] were used for biotin labeling of erythrocytes. With improved syntheses, pure BNHS (mp, 212 degrees-214 degrees C) and the spacered intermediate for C-BNHS, 6-(biotinylamide) hexanoate (mp, 225 degrees-226 degrees C) were obtained in an overall yield of 86%; the yield of C-BNHS (mp, 167 degrees-169 degrees C) was 68%.

Antilymphocytic antibodies and marrow transplantation. XIV. Antibody-induced suppression of graft-versus-host disease in C3-decomplemented mice differentiates two T-cell-depletion pathways.

Remarkable differences in the suppression of graft-versus-host disease (GVHD) have been found for anti-Thy-1 antibodies to relate to (1) antigen density and antibody coating on the target cells, (2) antibody isotype, and (3) uptake of complement subcomponent C1q. Regarding (2) and (3) we now demonstrate that depletion of the third complement component C3 by cobra venom factor (CVF) differentiates two T-cell elimination pathways in mice: four rat IgG2c anti-Thy-1 monoclonal antibodies (MoAbs) with low uptake of mouse C1q lost most of their T-cell-depleting and consequently GVHD-preventing effect in C3-depleted H2 IA incompatible semiallogeneic (C57BL/6xCBA)F1 mice. In contrast, eight rat IgG2b, mouse IgG2a, and 2b anti-Thy-1 MoAbs with high affinity for C1q still remained strongly T-cell-depleting and prevented GVHD even in fully mismatched CBA mice depleted of C3.

Monoclonal antibodies to complement components without the need of their prior purification. II. Antibodies to mouse C3 and C4.

Rat monoclonal antibodies (MAbs) to mouse complement components C3 and C4 were produced by immunizing rats with cell-bound C3 and C4. This principle involves: a) using mouse thymocytes coated with syngeneic rat antibody isotypes that show high affinity to C1q, b) the intercalation of C1q from serum and c) the subsequent activation of the classical complement pathway leading to deposition of cell-bound complement components. Screening for anti-complement antibodies was performed on antibody coating microtiter plates with mouse serum as source of complement.

Antilymphocytic antibodies and bone marrow transplantation. XI. Evidence that reduced Thy-1 expression in Thy-1.1 mice prevents suppression of graft-versus-host disease with anti-Thy-1 monoclonal antibodies.

Considerable variations in the suppression of graft-versus-host disease with monoclonal anti-Thy-1 antibodies were found to relate to substantial differences noted in the expression of mouse Thy-1 marker on lymph node and spleen cells of Thy-1.1 (AKR/J, C57BL/6.Thy-1.

Monoclonal antibodies that bind to hemopoietic stem cells: characterization and immunohistochemical localization of cells expressing gp50-65.

The cell surface of hemopoietic stem cells has been shown to express several antigens in common with more mature hemopoietic cells. One set of stem cell antigens is defined by a group of three monoclonal antibodies (13C6, 1C10, and 1A9), selected on the basis of binding to subpopulations of spleen colony-forming stem cells (CFU-S). These antibodies are shown to recognize cell surface glycoproteins of 50-65 kd (gp50-65) that occur widely on hemopoietic cells.

Monoclonal antibodies to complement components without the need of their prior purification. I. Antibodies to mouse C1q.

Rat monoclonal antibodies (MAbs) reactive with mouse complement subcomponent C1q were raised applying a principle that requires minute amounts of serum and circumvents purification of serum-derived C1q. The principle involves a) using the high affinity of certain cell-bound antibody isotypes for intercalating C1q from serum of various species, b) selecting such antibodies as are syngeneic to the immunized animal species, thus avoiding the production of antibodies against the intercalating antibodies and c) screening for the anti-C1q MAb in microtiter plates coated with C1q-intercalating MAb isotypes that are heterogeneic to the immunized animal species. We could establish 3 MAbs of IgM subclass, whose reactivity to mouse C1q was shown by ELISA techniques.