Factors controlling the recirculation of hematopoietic stem cells. IV. The effect of thymosin on the migration and differentiation of hematopoietic stem cells

Thymosine, a thymus hormone, restores the thymectomy induced deterioration of the routine pathways of migration and differentiation ofhemopoietic stem cells in mice. Administration of thymosine together with bone marrow cells from thymectomized mice to irradiated recipients also restores the level of migration and differentiation of hemopoietic stem cells. The inducing effect of thymosine on the maturation of T-lymphocyte precursors, which in their turn restore the usual rate of migration and differentiation of hemopoietic stem cells, has been suggested.     

Effect of antiserum against isologous aggregated immunoglobulins on the delayed-type hypersensitivity in mice immunized with sheep red blood cells

The mouse antiserum against isologous aggregated immunoglobulins (MAAS) injected to mice sensitized with 10(5) sheep red blood cells (SRBC) did not influence the delayed-type hypersensitivity (DTH) tested on the peak of sensitization (the 4th day) but enhanced significantly DTH tested on the 6th day. MAAS completely abolished the DTH suppression observed after sensitization with 5 x 10(7) SRBC. In transfer experiments the number of the DTH suppressor cells decreased in the spleen of sensitized mice under the MAAS action. MAAS did not affect the proliferation of antibody-forming cells (AFC) and hemagglutinin production but reduced by 70% the number of rosette-forming cells (RFC) in the spleen on the peak of the initial immune response. The data obtained may indicate that RFC participate in DTH suppression.     

Correlation between active rosette formation and delayed cutaneous hypersensitivity in experimental allergic encephalomyelitis

The effect of encephalitogenic myelin basic protein, BP, on active rosette-forming T cells (ARFC) was compared to that of nonencephalitogenic peptide S42, a synthetic analogue of the tryptophan region of BP. Depression of ARFC by these antigens was reversible within 24 h after a second dose of the antigen into the skin, or after in vitro incubation of lymphocytes with the sensitizing antigen (Ag-ARFC). The ratio of Ag-ARFC to ARFC rose with time following the sensitization but fell shortly before the clinical onset of experimental allergic encephalomyelitis in animals sensitized with BP. In contrast, the Ag-ARFC/ARFC ratios for animals sensitized with peptide S42 reached plateau levels from which they did not drop. The kinetics of the Ag-ARFC/ARFC responses paralleled those for delayed-type skin hypersensitivity (DTH) in the respective animals. The DTH responses rose following sensitization and fell shortly after the appearance of clinical signs of EAE. The results of this study provide in vitro and in vivo evidence for sensitization to myelin basic protein, and focus attention on the ARFC as a measure for an immunologically active cell population which may be quantitated by antigenic stimulation.Abbreviations used in this report EAE experimental allergic encephalomyelitis - DTH delayed-type skin hypersensitivity - ARFC active rosette-forming T cells - Ag-ARFC antigen-stimulated active rosette-forming T cells - TRFC total rosette-forming T cells     

Effect of inhibitors of nucleic synthesis on induction of the secondary immunologic response in vitro

The authors studied the influence of the DNA and RNA inhibitors on the formation of antibody-forming cell populations in induction of a secondary immunological response in vitro. Low concentrations of cytosine-arabinoside, the DNA synthesis inhibitor, increased the count of indirect hemolysin-forming and rosette-forming cells; its high concentrations depressed the secondary immunological response induction in the direct hemolysin-forming cell system more intensively than in the indirect cell system. Actinomycin D depressed the stimulation of secondary immunological response in vitro both in the systems of direct and indirect hemolysin-forming, and of rosette-forming cells.     

Selective concurrent suppression of the process of rosette-forming cell accumulation during the immune response]

Repeated injections to mice of normal rabbit immunoglobulins preceding immunization with sheep erythrocytes inhibited the accumulation of rosette-forming cells (RFC) in the spleen, without influencing the proliferation of the antibody-forming cells and hemaggutinin production. Reduction of the RFC under these conditions occurred on account of B-cells whose antigen-binding receptors could be blocked by antibodies against the aggregated mouse immunoglobulins and a complex of polyadenylic-polyuridylic acids. Repeated injections of the competitive antigen enhanced the formation of the immunological memory to the second antigen. The problem of the origin of the immune rosette-forming B-cells and their influence on the formation on the immunological memory is discussed.     

Enhancement of the immune response to surface antigens of the influenza B virus as a result of their covalent binding with a synthetic polymer carrier

The primary immune response (the number of antibody-forming cells, AFC) and the delayed type hypersensitivity (DTHS) were studied in mice immunized either with isolated glycoproteins of influenza virus (hemagglutinin, HA and HA plus neuraminidase, HA plus NA) or with their conjugates with an acrylic acid copolymer (CP) and N-vinylpyrrolidone of equimolar composition. Immunization of mice with conjugates containing virus proteins (virogates-HA-CP or HA plus NA-CP--entailed a 50-100 increment of the number of IgM- and IgG-AFC, anti-HA as compared with analogous parameters during immunization of animals with isolated virus proteins. Immunization of mice with the virogate HA-CP gives rise to the development of a more pronounced DTHS to HA. The authors discuss the possibility of the use of this basically new approach to the design of highly immunogenous vaccine preparations, effective in the control of influenza and other virus diseases.     

Endocrine function of apudocytes in immunocompetent organs during different forms of immune response

Histochemical methods devised by Masson, Sevka and Dominichi and immunohistochemical methods were used to establish that immunization markedly changes both qualitative and quantitative characteristics of the hormonal production of APUD cells in immune organs. The differences in the function of the APUD-system of immunocompetent organs were recorded on the primary and secondary immune responses as well as during sensitization in the development of the immediate type hypersensitivity. The most intense changes occurring in different forms of immune response were noticed at the level of serotonin- and catecholamine-containing APUD cells of the immune system.     

Specific experimental therapy in sensitization to group A streptococci]

A model of delayed hypersensitivity to Streptococcus hemolyticus, group A, were obtained in guinea pigs and rabbits. Studies of spontaneous changes of the immuno-allergic reactivity revealed that after a month of sensitization there developed delayed hypersensitivity only; according to the results of late skin tests it lasted not less than 6 months (the duration of investigation). The delayed hypersensitivity component began to manifest itself in 2 1/2 to 3 months and increased later on. Specific hyposensitization was performed with streptococcus allergens differing by physico-chemical conditions, i.e. the corpuscula allergen, the one that was lysed by ultrasonic waves, and Ando-Verzhikovsky's allergen. The latter had the most intensive hyposensitizing features. Specific hyposensitization was more demonstrative after the intracutaneous long-term course injections of threshold doses. Administration of subthreshold doses, as well as subcutaneous or intravenous injections of the allergen, was ineffective.     

Antibody-forming capacity of mouse spleen cells after hypoxic hypoxia and the administration of erythropoietin

In CBA mice the absolute and relative (per 10(6) spleen cells) number of antibody-forming cells (AFC) in the spleen was cut by half on the 1st, 4th, and 7th days after acute hypoxia (12 hours, 6700 m), and on the 1st and 4th days after cessation of chronic hypoxia (16 days, 16 hours, 6700 m). The number of AFC in the spleen returned to the normal level on the 7th day after cessation of chronic hypoxia. Single or double erythropoietin injections caused approximately a 1.15--2-fold decrease in spleen AFC number in posthypoxic mice in comparison with control animals.     

Preparation of mouse antiserum against isologous aggregated immunoglobulins and its effect on rosette forming cells]

A method of obtaining antisera against isologous aggregated mouse immunoglobulins is described. This serum designated MAAS blocked in vitro the antigen-binding receptors of the immune rosette-forming cells. MAAS was injected to mice immunized with SRBC. In comparision with the immunized mice given normal isologous serum rosette-forming B-cells were absent in the spleen of mice given MAAS at the peak of isologous response. But the antibody-forming cell count was not decreased under the influence of MAAS.     

The effect of IgE-mediated mast cell degranulation on the expression of experimental contact sensitivity in the mouse

The effects of mast cell activation/degranulation on the elicitation of contact sensitivity (CS) to oxazolone and dinitrofluorobenzene were investigated. Mice were actively sensitized to oxazolone by epicutaneous painting followed by ear challenge. Passive sensitization to DNFB was induced by intradermal injections of dinitrophenol (DNP)-specific cloned T cells in the ears. Mast cells in the challenged ears were activated in various time periods by inducing a passive cutaneous anaphylaxis reaction where passive sensitization with monoclonal IgE anti-DNP antibodies was followed by iv injection of DNP-BSA. This combination of immediate and delayed-type hypersensitivity reactions resulted in a significant increase of ear swelling without any noticeable effect on cellular infiltration when the contact response was evaluated a short time (3-4 hr) after mast cell activation. The very same results were obtained in naive (unsensitized) mice, indicating that this reaction was nonspecific. However, when the CS reaction was evaluated at its peak, i.e., 24 hr post challenge, mast cell activation that had been induced 0.5-11 hr after ear challenge did not have any significant effect on both swelling and cellular infiltration when the latter was evaluated by a radiometric assay. We conclude that in these systems mast cell activation/degranulation makes little or no contribution to the modulation of T-cell activity.     

Nonantibody-mediated suppression of delayed hypersensitivity to human gamma-globulin in mice.

Development of delayed hypersensitivity (DHS) to human γ-globulin (HIgG) in mice was documented by histological analysis, by the kinetics of footpad swelling in animals exhibiting humoral or delayed responses, and by the failure of sera to transfer delayed reactions to normal, syngeneic recipients. Since cyclophosphamide (CY) treatment resulted in diminished humoral and augmented delayed reactions, we used this as a tool to explore the nature of the regulatory mechanisms which affect expression of this type of cell-mediated immunity. In order to evaluate the effect which the presence or absence of antigen-specific cells might exert on expression of DHS, we subjected mice to experimental regimes which would result in lymphocyte proliferation or depletion, respectively (see Bachvaroff, R., and Rapaport, F. T., Cell. Immunol. 15, 336, 1975). Cell proliferation was induced by injection of 80 μg of aqueous antigen on Day ?4; this was followed by sensitization with HIgG-CFA (Freund's adjuvant) on Day 0, and footpad challenge on Day 13. These mice exhibited strong humoral reactivity; three of six died of anaphylaxis following footpad challenge, and the remaining three showed a diminished delayed response. Similarly treated mice that, in addition, received 6 mg of CY 3 days after injection of aqueous antigen and, therefore, would have antigen-specific cells present showed greatly diminished humoral reactivity, due to B-cell depletion. However, they also exhibited a marked diminution in delayed responsiveness. The data clearly demonstrate that a nonantibody-mediated, possibly cell-directed, regulatory influence is exerted on DHS where cell proliferation has occurred. We next examined the impact which the depletion of proliferating cells would exert on the expression of DHS. Cell depletion was attempted by giving one injection of aqueous antigen (Day 0) early in a regime of chronic CY administration (Days ?1 through +3) ; antigen-induced proliferating cells would be susceptible to CY and, therefore, depleted under these conditions. The results show that mice receiving both aqueous antigen and CY have depressed humoral and markedly diminished delayed reactivity compared to animals that were injected with CY alone. Thus, the augmenting effect which CY exerts on DHS is abrogated by stimulation with aqueous antigen. One interpretation is that CY removes a regulatory cell population in the normal animal, thereby allowing enhanced expression of delayed responsiveness. Clearly, regulatory function cannot be attributed solely to bumoral antibody production.     

The activating effect of ceruloplasmin on the development of delayed hypersensitivity in mice

The influence of ceruloplasmin on the development of delayed hypersensitivity (DHS) and activity of T-suppressors were studied in experiments on intact Balb/c mice. Ceruloplasmin introduced in a dose of 5 mg per 1 kg of weight a day before immunization of animals is shown to have a stimulating effect. The amount of the introduced drug being raised to 200 mg per 1 kg of weight suppressed the ability of organism to form DHS effect rather than increased it. Ceruloplasmin is stated to inhibit induction of DHS suppressors and to exert no effect on the expression of functional activity of the formed suppressors.     

Density gradient fractionation of mouse lymphoid tissues. II. Effects of anti-thymus and anti-bone marrow sera

The origin of antigen-binding (rosette-forming) and antibody-forming (plaque-forming) cells in mouse spleen is determined with the use of anti-thymus (anti-theta) and anti-bone marrow (anti-beta) sera. Evidence is presented that anti-theta serum is specific for thymus and thymus-derived cells. Anti-beta serum acts only on bone marrow and bone marrow-derived cells and does not affect the viability or functional activity of thymus cells. The cytotoxic activity of anti-theta and anti-beta serum does not overlap.     

Effect of some stressors on the mitotic regimen of the corneal epithelium and on the level of aneuploid bone marrow cells of adrenalectomized albino rats

It has been shown that pyrogenal administration or one-hour hyporthermia at 28--30 degrees C did not induce development of reactive inhibition in adrenalectomized rats but produced a significant increase in the level of pathological mitoses in the cornea of intact (from 4.3% to 6.3%) and adrenalectomized (from 10.6% to 12.5%) rats subjected to stress. The karyotypic analysis of the bone marrow cells under such conditions showed a significant rise in the number of aneuploid (hupo- and hyperdiploid) cells.     

Mechanism and epidemiology of laboratory animal allergy

Laboratory animal allergy (LAA) is a form of occupational allergic disease. The development of laboratory animal allergy is due to the presence of IgE antibodies directed against animal proteins. The process of sensitization (development of IgE antibodies) is a complex process which involves interaction of antigen presenting cells and lymphocytes of the Th-2 cell type. These cells generate a host of cytokines and other factors which lead to immediate hypersensitivity reactions and other factors which lead to immediate hypersensitivity reactions and the generation of allergic inflammation. Typical symptoms of laboratory animal allergy include nasal symptoms, such as sneezing, watery discharge, and congestion. Skin rashes are also common. Asthma, which produces symptoms of cough, wheezing, and shortness of breath, may affect 20-38% of workers who are sensitized to laboratory animal allergens. Rarely a generalized, life-threatening allergic reaction (anaphylaxis) may occur. The estimated prevalence of laboratory animal allergy is variable depending on the method used for diagnosis, but nonetheless may affect up to 46% of exposed workers. The presence of pre-existing allergies to non-work place allergens (e.g., dust mite, pollens, molds), exposure to laboratory animal allergens, and possibly tobacco smoking are risk factors for the development of laboratory animal allergy. Progress in the understanding of the mechanism and epidemiology of laboratory animal allergy will lead to improved methods for its prevention.     

Immunogenic and adjuvant properties of rat erythrocytes subjected to exposure to a high external temperature

The erythrocytes of Wistar rats, subjected to heating at 40 degrees C (4 times, each heating lasting 40 min.) were found to be more immunogenic in mice than the erythrocytes of intact rats. The immunization of intact Wistar rats, in a single injection, with syngeneic erythrocytes obtained from the heated animals did not induce immunological response reaction, whereas 5 injections of these erythrocytes caused an increase in the number of rosette-forming cells. The injection of syngeneic erythrocytes obtained from the heated rats to intact animals also stimulated the development of immune response to sheep erythrocytes.     

Development of delayed hypersensitivity to sheep erythrocytes after separate and combined administration of the antigen and cyclophosphamide]

The ability to the development of delayed hypersensitivity (DHS) to the appropriate antigen was studied in mice treated with large doses of SRBC and cyclophosphamide at varying time prior to the experiment. Suppression of DHS development induced by administering either the cytostatic alone or a large dose of the antigen was examined at the same periods of time. The combined treatment was shown to induce tolerance according to diverse tests for DHS (skin and macrophage migration inhibition tests). At the basis of this tolerance lies genuine deficiency of the appropriate clone of T cells. Administration of cyclophosphamide alone leads to a slight suppression of DHS, while a large dose of the antigen induces a different form of areactivity due to the suppressor cells whose nature is not yet clear.     

Nature of the human immune response to exposure to protein-producing microorganisms

The influence of the live culture and dried biomass of yeast-like fungi of the genus Candida on the characteristics of immune response in 1094 persons exposed to different concentrations of these fungi was studied. The subjects developed sensitization, manifested by immediate and cellular hypersensitivity reactions, as well as by disturbances in T-dependent and humoral immunity. The pattern of the detected changes depended on the concentration of the active factors and on the systemic condition of the subjects. Live fungal cells showed higher antigenic potency and were conducive to the development of allergic symptoms.