bluuebunny/crossref_metadata_2025_split huggingface dataset:
CELL INTERACTIONS IN THE IMMUNE RESPONSE IN VITRO
Authors: Feldmann Marc 
Published: June 2004

The mechanism of interaction of T and B lymphocytes was investigated in an in vitro hapten carrier system using culture chambers with two compartments separated by a cell impermeable nucleopore membrane. Because specific cell interaction occurred efficiently across this membrane, contact of T and B lymphocytes was not essential for cooperation which must have been mediated by a subcellular component or "factor." By using different lymphoid cell populations in the lower culture chamber and activated thymus cells in the upper chamber (with antigen present in both), it was found that the antigen-specific mediator acted indirectly on B cells, through the agency of macrophages. Macrophages which had been cultured in the presence of activated T cells and antigen acquired the capacity to specifically induce antibody responses in B cell-containing lymphoid populations. Trypsinization of these macrophages inhibited their capacity to induce immune responses, indicating that the mediator of cell cooperation is membrane bound. By using antisera to both the haptenic and carrier determinants of the antigen as blocking reagents, it was demonstrated that the whole antigen molecule was present on the surface of macrophages which had been exposed to activated T cells and antigen. Because specifically activated T cells were essential a component of the antigen-specific mediator must be derived from these cells. By using anti-immunoglobulin sera as inhibitors of the binding of the mediator to macrophages, the T cell component was indeed found to contain both κ- and µ-chains and was thus presumably a T cell-derived immunoglobulin.
It was proposed that cell cooperation is mediated by complexes of T cell IgM and antigen, bound to the surface of macrophage-like cells, forming a lattice of appropriately spaced antigenic determinants. B cells become immunized by interacting with this surface. With this mechanism of cell cooperation, the actual pattern of antigen-B cell receptor interactions in immunization would be the same with both thymus-dependent and independent antigens. An essential feature of the proposed mechanism of cell cooperation is that macrophage-B cell interaction must occur at an early stage of the antibody response, a concept which is supported by many lines of evidence. Furthermore this mechanism of cell interaction can be elaborated to explain certain phenomena such as the highly immunogenic macrophage-bound antigen, antigenic competition, the distinction between immunity and tolerance in B lymphocytes, and the possible mediation of tolerance by T lymphocytes.
ONTOGENY OF BURSAL FUNCTION IN CHICKEN
Authors: Toivanen Paavo , Toivanen Auli , Good Robert A. 
Published: June 2004

To study the occurrence of immunocompetent cells directly responsible for antibody production, cells from yolk sac, embryonic liver, bursa of Fabricius, bone marrow, spleen, or thymus were injected together with SRBC and Brucella abortus into 4-day old cyclophosphamide-treated chicks. A second stimulation was given 4 days later, and samples taken 4 days thereafter were used for antibody titrations.
During ontogeny, immunocompetent cells appeared in significant numbers first in the spleen for anti-SRBC responses, but in the bursa for anti-Brucella responses. Later these cells were also found in thymus and bone marrow. In the bursa, cells immunocompetent for anti-SRBC response were not encountered in significant numbers. The slight response to SRBC by transferred bursa cells reflects the presence of stem cells and their immediate descendents in the bursa at different stages of development.
These findings are compared with the development and maturation of the stem cell responsible for humoral immunity. In the bursa, development of the stem cell population precedes that of immunocompetent cells. The opposite relationship was found in bone marrow, spleen, and thymus where immunocompetent cells were always present some weeks before the appearance of cells capable of achieving a long-lasting reconstitution of bursa-dependent functions. These observations reveal that the bursa seeds out immunocompetent cells during its entire postembryonic development, but does not release the lymphoid stem cell population before this population has matured sufficiently and before the bursa itself, after fulfilling its function, starts to involute.
CELLULAR RECEPTORS: BINDING OF RADIOACTIVELY LABELED ANTI-ALLOANTISERUM
Authors: Binz Hans , Lindenmann Jean 
Published: June 2004

Rat alloantisera of the following specificities were obtained after single skin graft rejection: DA anti-BN, BN anti-DA, DA anti-Lewis, and Lewis anti-DA. Anti-alloantibodies were raised by injecting the first two alloantisera into (DA x BN)F1 hosts and the last two alloantisera into (DA x Lewis)F1 hosts. In this manner, four anti-alloantisera were raised: anti-(DA anti-BN), anti-(BN anti-DA), anti-(DA anti-Lewis), and anti-(Lewis anti-DA). From each anti-alloantiserum a gamma globulin fraction was prepared and trace labeled with 125I.
The labeled anti-alloantibodies could be shown to be fixed preferentially by red cells coated with the alloantibody used to induce them. They were also preferentially fixed by normal rat lymphoid cells presumed to carry recognition structures similar to alloantibody. For instance, anti-(DA anti-BN) was fixed by BN red cells coated with DA anti-BN and by normal DA lymphoid cells presumed to carry RS(BN). Conversely, anti-(BN anti-DA) was fixed by DA red cells coated with BN anti-DA and by normal BN lymphoid cells, carrying RS(DA).
Absorption and inhibition experiments showed that alloantibodies and normal lymphoid cells compete for the same labeled anti-alloantibodies. We conclude that cellular receptors and circulating alloantibody are antigenically similar: They have the same aliotype.
LIGAND-INDUCED MOVEMENT OF LYMPHOCYTE MEMBRANE MACROMOLECULES
Authors: Unanue Emil R. , Perkins William D. , Karnovsky Morris J. 
Published: June 2004

The fate of different complexes on the membrane of thymocytes and spleen lymphocytes was studied with the use of both immunofluorescence and ultrastructural radioautography. The complexes of anti-immunoglobulin (Ig) with the surface Ig of B lymphocytes were present all around the membrane at 4°C; an increase in temperature produced a rapid aggregation of the complex into a cap which was readily interiorized in vesicles. Ultrastructural details of this process were given. The movement of the complexes depended upon the amount of anti-Ig and the temperature.
The complexes of anti-lymphocyte antibody with surface antigen(s) did not result in formation of a single large aggregate (or cap) unless an anti-antibody was brought into the reaction. The caps formed by this trilayered complex were not interiorized. Concanavalin A (Con A) bound to cell surface carbohydrate moieties and the complexes of Con A readily formed a cap and were interiorized. Finally, antibodies to H-2 determinants did not form in most instances a single cap aggregate even when anti-antibodies were used. With time the H-2 complexes tended to form several large aggregates with some endocytosis.
LASTING BIOLOGICAL EFFECTS OF EARLY ENVIRONMENTAL INFLUENCES
Authors: Lee Chi-Jen , Dubos Rene 
Published: June 2004

The effects of neonatal infection, perinatal malnutrition, and crowding on the metabolism of brain catecholamine were studied in specific pathogen-free mice. Metabolic turnover of catecholamine was determined by measuring the incorporation of precursor tyrosine-14C into brain tissue, catabolic activity of norepinephrine-3H at various times after intracisternal injection, and tissue levels of dopamine and norepinephrine.
The rate of tyrosine incorporation was decreased by neonatal infection but was increased by perinatal malnutrition and crowding. There was no difference in catabolic activity of norepinephrine between infected, crowded, and control groups. In the malnourished group, however, the total radioactivity from norepinephrine was significantly higher than in the control group ½ and 2 hr after injection.
The brain contents of dopamine and norepinephrine were depressed in the malnourished group. There was no significant difference in catecholamine levels between infected, crowded, and control groups.
In the malnourished group, treatment of the mothers with growth hormone prevented almost completely weight loss during lactation, and also resulted in higher fetal weight. Hormone treatment restored to normal the levels of brain catecholamine and the enzymatic activity of brain tyrosine hydroxylase in progeny of malnourished mothers.
THE INTERACTION BETWEEN TOXOPLASMA GONDII AND MAMMALIAN CELLS
Authors: Jones Thomas C. , Hirsch James G. 
Published: June 2004

Electron microscope methods have been used to study delivery of macrophage primary or secondary lysosomal contents to phagocytic vacuoles containing living or dead toxoplasmas. Secondary lysosomes were labeled by culturing the cells in colloidal thorium dioxide (thorotrast) or in ferritin. Acid phosphatase cytochemistry was employed for detection of primary as well as secondary lysosomal constituents. These various lysosomal labels were present in nearly all vacuoles containing toxoplasmas killed with glutaraldehyde, or in vacuoles containing those parasites undergoing degeneration 1 hr after the uptake of living toxoplasmas. In contrast, at times ranging from 1 to 20 hr after infection, no vacuoles containing morphologically normal, apparently viable toxoplasmas were thorotrast or ferritin positive, and only rarely did these vacuoles react for acid phosphatase. In many instances vacuoles containing viable toxoplasmas and no lysosomal markers were situated in the same cell nearby to vacuoles containing degenerating toxoplasmas and lysosomal constituents, thus indicating that the determinants of lysosomal fusion were operating locally in the immediate vicinity of the phagocytic vacuole, and not operating to influence general cell function. Thus, some toxoplasmas are able to prevent the delivery of lysosomal contents, and apparently the phagocytic vacuole provides for these parasites a sheltered microenvironment ideal for their growth.
Morphologic evidence indicated that living toxoplasmas altered the phagocytic vacuolar membrane in macrophages, fibroblasts, and HeLa cells. Within minutes after phagocytosis, the vacuole became surrounded by closely apposed strips of endoplasmic reticulum and mitochondria; somewhat later, microvillous protrusions of the membrane into the vacuole were seen. These morphologic features of phagocytic vacuoles containing living toxoplasmas may be of importance in relation to the absence of lysosomal fusion, or they may serve some function in protecting the host cell or in nourishing the parasite.
MOUSE THYMUS-INDEPENDENT AND THYMUS-DERIVED LYMPHOID CELLS
Authors: Lamelin J.-P. , Lisowska-Bernstein B. , Matter A. , Ryser J. E. , Vassalli P. 
Published: June 2004

The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen (MSLA and BAθ) or thymus-independent (B) cell mouse-specific bone marrow-derived lymphocyte antigen (MBLA) surface antigens allowed direct proof of the different specificity of these antisera by double immunofluorescence (IF) staining with selective visualization of fluorochromes. These antisera and antisera against mouse Ig and its different types of chains were then used with technique of either double IF staining or IF combined with radioautography, allowing the following conclusions:
(a) Surface Ig (sIg) was found exclusively on B cells and never on T cells, but not all B cells had sIg. Cells containing detectable amounts of Ig were MBLA+, but had less sIg than other B cells or none at all. There was evidence for the existence of a significant number of MBLA+ lymphocytes, neither bearing nor containing detectable Ig.
(b) µ-Chains were the most frequent but not the only heavy chains found on spleen cells; however, it could not be decided with the technique used, if a single cell can bear more than one type of heavy chain. No cell containing γ-chains was found to bear surface µ-chains, although a very few cells containing both µ- and γ-chains were observed.
(c) The antigen-binding cells detected after immunization with bacteriophage T4, bovine serum albumin, Maia squinado hemocyanin, and sheep erythrocytes were analyzed for MSLA, MBLA or sIg using double IF, a combination of IF and radioautography, or inhibition of "rosette" formation. Practically all the antigen-binding cells detected were MSLA-, MBLA+, sIg+.
(d) More B cells than T cells were found among short-lived lymphoid cells labeled by repeated in vivo injections of tritiated thymidine, but the results did not support a simplified concept equating T cells to long-lived and B cells to short-lived lymphocytes.
(e) Cells dividing rapidly in the lymph nodes draining the sites of immunization with various antigens were predominantly T cells 2 days after immunization and in majority B cells a few days later.
(f) Incubation of lymphoid cells at 37°C with rabbit anti-mouse Ig or anti-κ chains led to complete disappearance of sIg and to decrease of MBLA ("antigenic modulation"). In the same conditions, anti-MBLA gave partial modulation of MBLA and of sIg; MBLA, however, reappeared much faster than sIg. No modulation of T cell surface antigens by the appropriate antisera was observed. Cell treatment with Pronase could remove MBLA, sIg, MSLA, and BAθ, which reappeared within a few hours. Neuraminidase treatment was without detectable effect on these antigens.
IMMUNOLOGICAL TOLERANCE IN BONE MARROW-DERIVED LYMPHOCYTES
Authors: Katz David H. , Hamaoka Toshiyuki , Benacerraf Baruj 
Published: June 2004

Administration of the 2,4-dinitrophenyl (DNP) derivative of the copolymer of D-glutamic acid and D-lysine (D-GL) to inbred mice induces a state of DNP-specific tolerance in such animals irrespective of their immune status at the time of treatment. Taking advantage of the relative ease with which DNP-D-GL can induce tolerance in an animal previously primed with an immunogenic DNP-carrier conjugate, we have established conditions for tolerance induction in an adoptive cell transfer system. Thus, the adoptive secondary anti-DNP antibody response of DNP-keyhole limpet hemocyanin (KLH)-primed spleen cells was completely, or almost completely, abolished by exposure of such cells to DMP-D-GL either in vivo or in vitro. Tolerance induction in vivo occurred irrespective of whether the DNP-primed cells were exposed to DNP-D-GL in the donor animal before adoptive transfer or in recipient mice after transfer. In the latter situation, it was possible to show that tolerance induction in this model occurs very rapidly (1 hr) and with relatively low doses of tolerogen (50 µg). Incubation of DNP-KLH-primed cells with DNP-D-GL in vitro under varying culture conditions also resulted in depression of the adoptive secondary response of such cells, although the kinetics and degree of tolerance induction in this way were slightly different from that obtained by in vivo tolerization.
Utilizing the adoptive transfer tolerance system, it was possible to approach certain questions concerning the mechanism of tolerance induction and fate of tolerant bone marrow-derived (B) lymphocytes in the DNP-D-GL model. The possibility that suppression of anti-DNP antibody from the DNP-D-GL reflects blocking of surface receptor molecules on B lymphocytes has been ruled out by several experimental observations. The most conclusive evidence on this point derives from the failure of enzymatic treatment with trypsin to reverse the tolerant state induced by in vitro exposure of primed cells to DNP-D-GL, whereas trypsinization completely restored the immunocompetence of DNP-KLH-primed cells rendered unresponsive by exposure to DNP-ovalbumin in vitro. The present studies also demonstrate that the tolerant state induced by DNP-D-GL represents a predominantly irreversible inactivation of specific B lymphocytes. This conclusion is derived from experiments in which it was found that tolerance was maintained through as many as two serial adoptive transfers performed over a period of time of at least 24 days from the single exposure of such cells to the tolerogen. Moreover, the possibility that maintenance of tolerance through such serial transfers was due to inadvertent transfer of tolerogenic doses of DNP-D-GL was definitively ruled out. It appears, therefore, that DNP-specific tolerance induced by DNP-D-GL is an example of irreversible inhibition of cell reactivity to antigen reflecting yet-to-be-determined events at the intra- and subcellular levels.
ANTIGEN RECOGNITION AND THE IMMUNE RESPONSE
Authors: Bush Maurice E. , Alkan Sefik S. , Nitecki Danute E. , Goodman Joel W. 
Published: June 2004

L-Tyrosine-p-azobenzenearsonate (RAT) induces cellular immunity without humoral antibody in guinea pigs. Asymmetric bifunctional antigens composed of one RAT moiety and one dinitrophenyl (DNP) group separated by flexible spacers induce anti-RAT cellular immunity and an anti-DNP humoral response. Symmetrical bifunctional antigens of similar design but comprised of two RAT determinants induce cellular immunity without demonstrable anti-RAT antibody. However, when the flexible spacer is replaced by a rigid decaproline chain, humoral anti-RAT responses are provoked.
Since RAT contains both electropositive (azo) and electronegative (arsonate) centers, the failure of bifunctional RAT compounds with flexible spacers to induce humoral immunity might be ascribed either to intramolecular stacking, which compromises their bifunctional character, or to interaction of both determinants with receptors on the same cell surface, which would fail to satisfy the requirement for cooperation. In order to distinguish between these alternatives, symmetrical bifunctional antigens composed of two L-tyrosine-p-azophenyltrimethylammonium (TAT) determinants separated by flexible or rigid spacers were synthesized. TAT is immunogenic and does not cross-react with RAT. Furthermore, it contains only electropositive centers and consequently bifunctional molecules do not undergo intramolecular stacking. Immunization with either flexibly or rigidly spaced bifunctional TAT antigens raised anti-TAT antibody. These results conclusively demonstrate that "self-help," cooperation between bone marrow-derived and thymus-derived lymphocytes of identical or similar specificity, can occur, provided the determinants on the antigen are prevented from associating with each other.
IMMUNE RESPONSES AGAINST NATIVE AND CHEMICALLY MODIFIED ALBUMINS IN MICE
Authors: Schirrmacher Volker , Wigzell Hans 
Published: June 2004

Immune cells induced by bovine serum albumin (BSA) and its methylated derivative (MBSA) have been compared in a cooperative cell transfer system for their content of BSA-specific antibody-forming cell precursors (AFCP, B) and BSA-specific helper (T) cells. When MBSA immune cells were transferred together with hapten-primed cells into recipient mice which were stimulated by a hapten-BSA conjugate, their cooperative secondary anti-hapten response was as good as in case of transferred BSA immune cells. Their secondary anti-BSA response, however, was markedly reduced (reduction factor &gt; 30). Hapten-MBSA conjugates had the same capacity to react with BSA-specific helper cells in the cooperative secondary anti-hapten response as hapten-BSA conjugates but had a reduced ability to react with BSA-specific AFCP cells. In spite of the pronounced reduction of the B cell response, MBSA had the same threshold dose as BSA for activating BSA-specific T cells.
These data suggest that B and T cells recognize different epitopes on the BSA molecule, only those recognized by B cells being affected by the methylation procedure.
THE EFFECT OF GLUCOCORTICOSTEROIDS ON THE PROLIFERATION AND KINETICS OF PROMONOCYTES AND MONOCYTES OF THE BONE MARROW
Authors: Thompson Jan , van Furth Ralph 
Published: June 2004

To elucidate mechanisms underlying the prolonged monocytopenia induced in the peripheral blood of mice by injection of a subcutaneous depot of hydrocortisone acetate, the effect of this compound on the production of monocytes and their release from the bone marrow was studied.
Hydrocortisone was found to cause a rapid reduction of the bone marrow promonocytes to about 65% of their initial number. The number of monocytes in the bone marrow decreased gradually, over a period of 96 h, to 75% of the initial value.
The mitotic activity of the promonocytes was not diminished, as judged from the labeling in vitro with [3H]thymidine and the DNA-synthesis and cell-cycle times of these cells. The production of monocytes was only moderately diminished, i.e., to about 80% of the normal amount.
The release of monocytes from the bone marrow was found to be influenced by hydrocortisone. After in vivo labeling with [3H]thymidine the monocyte-labeling indices were initially significantly higher in hydrocortisone-treated than in normal mice.
It is concluded that a decreased production of monocytes in the bone marrow cannot account for the prolonged monocytopenia in the peripheral blood after hydrocortisone administration. However, hydrocortisone interferes with the release of newly formed monocytes from the bone marrow, resulting in a prolonged sojourn of these cells in this compartment.
PRODUCTS OF ACTIVATED LYMPHOCYTES
Authors: Sorg Clemens , Bloom Barry R. 
Published: June 2004

General methods were developed and applied to the biosynthesis and purification of products of activated lymphocytes available in minute quantities. The activity studied here was the migration inhibitory factor (MIF) produced by purified protein derivative (PPD)- or concanavalin A (Con A)-stimulated lymphocytes obtained from one guinea pig or less. The methods selected yielded results in terms of two chemical parameters characteristic of the molecules involved, namely Kd on Sephadex G-75 and isoionic point, pI, on isoelectric focusing.
When supernatants were fractionated on G-75 columns, there were several areas even in control supernatants which produced migration inhibition relative to medium controls. However, in PPD- and Con A-stimulated supernatants, at least one peak of MIF activity was found solely in the stimulated cultures, with a Kd of 0.15. A double-labeling technique was used to characterize the proteins of this peak. Control, unstimulated cultures were labeled with [14C]leucine and stimulated cultures were labeled with [3H]leucine. After mixing the supernatants and G-75 filtration, a major "ratiolabeled" broad peak. i.e. one with increased 3H/14C ratio, was found. When a narrow portion of this peak about Kd 0.15, containing most of the MIF activity, was subjected to analytical isoelectric focusing, all of the label was associated with proteins of lower net charge than albumin. A unique ratiolabeled peak was found in PPD- and Con A-stimulated fractions with a pI of approx. 5.3. A micropreparative isoelectric focusing technique was developed and yielded MIF activity in the same region as the major ratiolabeled peak. Further study will be required to ascertain whether the ratiolabeled protein is MIF. By following the Kd, pI, and 3H/14C labeling ratio, at least 14 products of activated lymphocytes, synthesized either de novo or in increased amounts, could be distinguished.