bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMMUNOCOMPETENT CELLS OF THE CHICKEN
Authors: McArthur W. P. , Chapman J. , Thorbecke G. J. 
Published: June 2004

Specific antisera to chicken thymus and to bursa of Fabricius were obtained in rabbits. After appropriate absorption and dilution all four anti-thymus sera, in the presence of guinea pig C', killed &gt;90% of thymus and ≦12% of bursa cells. They were cytotoxic for approximately 50% of spleen cells and did not affect antibody-forming cells. The surface antigen detected by these antisera was named chicken T-lymphocyte antigen (CTLA).
Two of four anti-bursa sera, under similar conditions, killed &gt;90% of bursa cells and ≦10% of thymus cells. These antisera were cytotoxc for a large percentage of antibody-forming cells and killed approximately 30% of spleen cells The other two anti-bursa sera were somewhat less potent but showed similar specificity. The surface antigen detected by these antisera was named chicken bursa-derived lymphocyte antigen (CBuLA).
Rabbit antisera to chicken immunoglobulin were cytotoxic for bursa but not for thymus cells and killed a similar percentage of spleen cells as did anti-bursa sera. They were also cytotoxic for antibody-forming cells.
PASSIVE ANTIBODY AND THE IMMUNE RESPONSE
Authors: McBride Raymond A. , Schierman Louis W. 
Published: June 2004

The isoimmune response of fowl inoculated with RBC coated with antibody was investigated. Anti-B antiserum from a single animal was used to coat different donor type RBC. With each donor type RBC the immune response to the coated determinants is suppressed. Enhancement of the immune response to noncoated determinants occurs when they are products of an allelic gene or belong to a different blood group system. Coating some B antigen determinants suppresses the response to noncoated determinants of the same antigen, i.e., determinants which are products of the same B gene. Varying the quantity of passive antibody revealed that the degree of suppression and the degree of enhancement are negatively correlated.
These findings support the concept that antibody-coated determinants function as carrier for noncoated determinants, provided a certain physical association exists between them. A further interpretation of these studies is that in certain situations an antibody to one antigen may interfere with events which lead to an immune response to a different antigen. The possibility, that the protection afforded by ABO incompatibility against Rh isoimmunization is because of a similar phenomenon, is discussed. A hypothesis is presented which states that where the immune response to certain antigens behaves as a dominantly inherited trait, and is associated with histocompatibility type, the nonresponder animals possess an antibody (perhaps cell bound) which interferes with the response to determinants for which it does not have specificity. Responders are assumed to lack this antibody because it has specificity for their major histocompatibility antigens.
TONE AND REACTIVITY OF VASCULAR SMOOTH MUSCLE IN GERMFREE RAT MESENTERY
Authors: Baez Silvio , Gordon Helmut A. 
Published: June 2004

Microcirculatory observations and measurements were made by in vivo microscopy in 35 germfree and 26 conventional rats. The rate of vasomotor activity, "vasomotion," of precapillary arterioles was found markedly decreased in the germfree animals.
All precapillary vessels in the germfree rats were markedly hyporeactive to the catecholamines, epinephrine and norepinephrine, as compared to similar vessels of conventional rats. The vessels in the germfree animals were also less responsive to vasopressin but not angiotensin.
A greater lumen:wall ratio of primary arterioles, but not of secondary arterioles and metarterioles, found in germfree animals is related to change in vessel lumen alone without concomitant change in wall thickness.
The germfree rat is characterized by possessing a hypotonic, catecholamine-refractory mesoappendix microvasculature.
MACROPHAGE-MELANOMA CELL HETEROKARYONS
Authors: Gordon Saimon , Cohn Zanvil 
Published: June 2004

Mouse peritoneal macrophages possess a specific plasma membrane receptor for antibody-coated particles. Sheep red cells coated with rabbit 7S antibody attach readily to the macrophage surface and are subsequently interiorized. The fusion of macrophage with nonphagocytic mouse melanoma cells produces heterokaryons in which the macrophage receptor is drastically altered. The receptor is present shortly after fusion and heterokaryons are actively phagocytic. The ability to bind and ingest red cells is, however, progressively lost over the next 12–24 hr and does not reappear thereafter.
Exposure of heterokaryons to trypsin (1–100 µg/ml for 30 min at 37°C) results in the reappearance of initial receptor activity and the unmasking of the surface receptor. This property is again lost upon subsequent cultivation. The masking process takes place when cells are cultivated in the absence of IgG so that the adsorption of antibody from the medium is not responsible for this phenomenon. Inhibition of heterokaryon protein synthesis preserves phagocytic activity in a reversible fashion and prevents the masking of macrophage receptors. Inhibition of melanoma RNA synthesis before fusion is also able to block subsequent masking, but is ineffective if delayed until after fusion. Ultraviolet irradiation of the melanoma cell before fusion prevents subsequent masking, whereas similar treatment of the macrophage has no effect.
Cells differ markedly in their ability to mask the macrophage phagocytic receptor after fusion. Ehrlich ascites tumor cells mask the receptor rapidly, primary chick fibroblasts minimally, and embryonic chick erythrocytes not at all.
STUDIES ON ANTIBODY-PRODUCING CELLS
Authors: Gudat Fred G. , Harris T. N. , Harris Susanna , Hummeler Klaus 
Published: June 2004

Mice injected with sheep RBC and then, 4 days later with thymidine-3H, were sacrificed on the day of thymidine-3H injection or 1 or 2 days later. Hemolytic antibody plaque preparations were made of cells from the draining lymph nodes by a thin-plating procedure permitting collection of isolated PFC for electron microscopic examination and radioautography.
Of cells obtained on the day of thymidine-3H injections, 65% of the labeled PFC were in the lymphocytic category, in comparison with 13% found previously in the entire population of such cells. The remaining 35% were plasmablasts in early stages of differentiation. Cells obtained 1 day after the thymidine-3H injections showed a shift to a majority of labeled cells in the plasmacytic category. Also, the plasmablasts were substantially more differentiated than those of the previous day, and some mature plasma cells were now seen. The labeled PFC obtained on day 2 gave no indication of further differentiation.
Cells of rabbit lymph nodes labeled in vitro with thymidine-3H showed a range of labeled PFC. The majority were in the plasmacytic category, including some mature plasma cells.
The data from the experiments with in vivo labeling suggest a direct differentiation from antibody-synthesizing lymphocytes to plasma cells. Further, the in vivo experiments indicated that differentiation from nascent lymphocyte to plasma cell could be essentially completed within 1 day.
CELL-TO-CELL INTERACTION IN THE IMMUNE RESPONSE
Authors: Miller J. F. A. P. , Sprent J. , Basten A. , Warner N. L. , Breitner J. C. S. , Rowland G. , Hamilton J. , Silver H. , Martin W. J. 
Published: June 2004

Experiments were designed to test the possibility that thymus-derived (T) cells cooperate with nonthymus derived (B) cells in antibody responses by acting as passive carriers of antigen. Thoracic duct lymphocytes (TDL) from fowl γG-tolerant mice were incubated in vitro with fowl anti-mouse lymphocyte globulin (FALG), which was shown not to be immunosuppressive in mice. On transfer into adult thymectomized, irradiated, and marrow protected (TxBM) hosts together with a control antigen, horse RBC, a response to horse RBC but not to fowl γG was obtained. By contrast, TxBM recipients of nontolerant, FALG-coated TDL responded to both antigens and the antibody-forming cells were shown to be derived from the host, not from the injected TDL. These findings suggested that, under the conditions of the experiment, triggering of unprimed B cells in the spleens of TxBM hosts was not achieved with antigen-coated tolerant lymphocytes.
Another model utilized the ability of B cells to bind antibody-antigen complexes. Spleen cells from TxBM mice, incubated in vitro with anti-fowl γG-fowl γG·NIP, were injected with or without normal TDL (a source of T cells) into irradiated hosts. Only mice given both cell types could produce an anti-NIP antibody response. In a further experiment, spleen cells from HGG·NIP-primed mice were injected together with NIP-coated B cells (prepared as above) into irradiated hosts. A substantial anti-NIP antibody response occurred. If, however, the T cells in the spleens of HGG·NIP-primed mice were eliminated by treatment with anti-θ serum and complement, the NIP response was abolished. It was concluded that antigen-coated B cells could not substitute for T cells either in the primary or secondary response.
Treatment of T cells from unprimed or primed mice with mitomycin C impaired their capacity to collaborate with B cells on transfer into irradiated hosts. Taken together these findings suggest that before collaboration can take place T cells must be activated by antigen to differentiate and in so doing may produce some factor essential for triggering of B cells.
NEW APPROACHES FOR THE LABORATORY RECOGNITION OF M TYPES OF GROUP A STREPTOCOCCI
Authors: Rotta Jiri , Krause Richard M. , Lancefield Rebecca C. , Everly William , Lackland Henry 
Published: June 2004

The successful classification of Group A streptococci by the capillary precipitin technique requires a complete series of M type antisera which are sufficiently potent and specific to give unequivocal type-specific reactions with all the serotypes. Specific antisera for this purpose have been prepared by absorption with heterologous streptococci.
Unabsorbed antisera have been employed here in the Ouchterlony double-diffusion agar-gel test to identify the M type of streptococci. Techniques have been developed for making this method of M typing fully reliable. The results reported here confirm and amplify the original findings of Michael and Massell (3). With crude HCl extracts and unabsorbed M type antisera, a precipitin line due to the M protein and another to the group-specific carbohydrate are the two major reactions observed. These reactions, however, are usually readily distinguishable. There was a surprising lack of cross-reactive precipitin lines due to non-type-specific protein antigens in the extracts.
Although many of the unabsorbed M type antisera can be employed in the double-diffusion tests, the group-specific antibody must be removed from some of the unabsorbed antisera to avoid confusing cross-reactions. Absorption of these antibodies has been achieved by means of a specific immunoabsorbent column prepared from para-aminophenyl-ß-N-acetylglucosamine and cyanogen bromide-activated Sepharose. Excellent agreement was observed between the M typing results obtained on 117 field strains by the conventional capillary precipitin method and the Ouchterlony double-diffusion method.
THE INFLUENCE OF POSTNATAL DEVELOPMENT ON DRUG-INDUCED HEPATIC PORPHYRIA AND THE SYNTHESIS OF CYTOCHROME P-450
Authors: Song Chull S. , Moses Harold L. , Rosenthal Alan S. , Gelb Nancy A. , Kappas Attallah 
Published: June 2004

The mitochondrial enzyme δ-aminolevulinate synthetase (ALAS) controls the rate-limiting step in the synthesis of porphyrins and heme. An experimental form of hepatic porphyria can be readily elicited in laboratory animals, such as the rat, by drugs and foreign chemicals which are known to enhance the de novo formation of this enzyme in the liver.
The present study shows that there is a striking refractoriness to the induction of ALAS during the perinatal period in the rat. Chemicals which have potent porphyria-inducing activity in adult animals have no significant inducing effect on hepatic ALAS in neonates. The ultrastructural changes which accompany the induction of ALAS by drugs and chemicals in adult liver also fail to take place in the livers of neonates. A progressive capacity for responding to the action of chemical inducers of hepatic ALAS does, however, develop in neonatal animals so that by approximately 5–6 wk of age experimental porphyria can be elicited as effectively in them as in adults.
The reasons for the refractoriness of hepatic ALAS to induction in the perinatal period are not known; but the findings of this study make it clear that ALAS belongs to that increasingly large group of liver enzymes in mammals whose appearance, increase of activity, or inducibility is developmentally determined.
The occurrence of developmental changes in the indicibility of ALAS in the liver of neonates also provided an opportunity to study the relationship of this enzyme activity to the drug-mediated induction of the hepatic hemoprotein cytochrome P-450. This inducible hemoprotein serves as the terminal oxygenase in the microsomal mixed-function oxidase system in the liver. The results of this study indicate that, in contrast to the refractoriness of ALAS to induction, significant drug-induced changes of hepatic P-450 content and of hemeprecursor incorporation into this cytochrome do take place in neonates. The synthesis of P-450 thus appears to be under a regulatory control different from that of ALAS in neonates, and the relation between ALAS activity and P-450 formation is not therefore a direct one.
CELLS MEDIATING SPECIFIC IN VITRO CYTOTOXICITY
Authors: Golstein Pierre , Svedmyr Erik A. J. , Wigzell Hans 
Published: June 2004

Spleen cells from mice immunized with allogeneic tumor cells are incubated on different fibroblast monolayers. The nonadsorbed cells are tested for cytotoxicity against 51Cr-labeled target cells. The cytotoxicity of nonadsorbed cells is much lower after incubation on fibroblasts syngeneic to the immunizing tumor cells than after incubation on fibroblasts syngeneic to the immune cells. This specific decrease of cytotoxic activity depends on the duration and temperature of incubation on monolayers. After incubation the monolayers are trypsinized and pure populations of adsorbed lymphocytes isolated by density gradient fractionation. The cytotoxicity of such trypsin-eluted, gradient-purified lymphocytes is much higher when these lymphocytes are isolated from fibroblasts syngeneic to the immunizing tumor cells than when they are isolated from fibroblasts syngeneic to the immune cells. These experiments demonstrate specific adsorption of immune cells onto fibroblasts carrying the immunizing antigens, and thus prove the existence of specific receptors at the surface of these immune cells.
Spleen cells from mice immunized with two types of allogeneic tumor cells bearing different H-2 antigen alleles are incubated on different fibroblast monolayers. The results of such experiments show a differential specific adsorption pattern, suggesting independent adsorption of two populations of immune cells bearing receptors directed against either one or the other immunizing H-2 antigen. The existence of at least a majority of cells, each of which is homogeneous as to the specificity of its receptors, makes it likely that specific receptors are synthetized by the cells that bear them. The role of specific receptor-bearing cells in the killing process is discussed.
SIGNIFICANCE OF BIVALENCE OF ANTIBODY IN VIRAL NEUTRALIZATION
Authors: Rosenstein Robert W. , Nisonoff Alfred , Uhr Jonathan W. 
Published: June 2004

The role of bivalence of antibody in its capacity to neutralize virus was studied with rabbit antibodies to the bacteriophage, ϕX174. Univalent Fab or Fab' fragments of IgG isolated from antiviral antisera obtained early in the immunization schedule had virtually no activity compared to that of the intact IgG. When the antibodies were isolated from antisera of the same rabbits several months later, the univalent fragments and IgG were essentially equal in activity. The results are interpreted on the basis that an IgG molecule, because of its bivalence, has a higher effective combining affinity (avidity) than a univalent fragment. After prolonged immunization, however, the affinity of univalent antibody becomes sufficiently high that it exceeds a threshold value, above which further increase in affinity, through bivalence, is no longer significant. The results could explain the variability in relative effectiveness of univalent antibodies observed in previous studies. These data, and the fact that F(ab')2 fragments from either "early" or "late" antisera were as effective as IgG, indicate that fragment Fc is not a significant factor in neutralization.
No differences in dissociation from the virus of univalent antibody from early and late antisera could be demonstrated by dilution at temperatures up to 47°C. The attachment at sites of neutralization on the virus appears to be functionally almost irreversible in this system.
CHOLESTEROL METABOLISM IN THE MACROPHAGE
Authors: Werb Zena , Cohn Zanvil A. 
Published: June 2004

Macrophage membrane cholesterol is present in two subcellular cholesterol pools, a rapidly exchanging compartment comprising about two-thirds of the total cholesterol, and a slowly exchanging compartment comprising one-third of the total. The morphological identification of the kinetically distinguishable pools proceeded by alteration of each compartment. Trypsin treatment markedly decreased the rate of cholesterol exchange without removing cholesterol from the membrane. Recovery of normal exchange rates took more than 7 hr and required protein synthesis. This suggested that a plasma membrane receptor is involved in positioning of lipoproteins for exchange, and is consistent with the plasma membrane localization of the rapidly exchanging compartment.
Extensive pinocytosis by nondegradable dextran, dextran sulfate, or sucrose resulted in the accumulation of many secondary lysosomes, thus increasing the relative proportion of intracellular membranes. The measurable granule membrane area, cholesterol content, phospholipid content, and the relative size of the slowly exchanging cholesterol compartment all increased. The amount of intracellular membrane altered by extensive phagocytosis of latex particles also increased the size of the slowly exchanging cholesterol compartment. This suggested that the slowly exchanging pool of cholesterol represented the intracellular membranes primarily of lysosomal origin.
Rabbit alveolar macrophages and thioglycollate-stimulated peritoneal macrophages contain many secondary lysosomes as a result of multiple bouts of in vivo phagocytosis and pinocytosis. In both of these cells the fast and slow pools are equal in size. The increased cholesterol content was attributable to the increase in the relative size of the slowly exchanging compartment. L-cells and melanoma cells also exchange their cholesterol with that of serum lipoproteins. Both cells contain few cholesterol-rich intracellular membranes, and had lower cellular cholesterol contents. In these cells the slowly exchanging pool was a minor contribution to cell cholesterol. Studies with these cells provided further evidence for the lysosomal membrane and plasma membrane localization of the slowly and rapidly exchanging cholesterol compartments.
REGULATION OF THE IMMUNE SYSTEM BY SYNTHETIC POLYNUCLEOTIDES
Authors: Stout Robert D. , Johnson Arthur G. 
Published: June 2004

Addition of polyadenylic-polyuridylic acid in complex form (poly A:U) without antigen to a suspension of spleen cells obtained from BALB/Aj mice primed 6 wk previously with human γ-globulin (HGG) resulted in an immediate fourfold increase over background number of anti-HGG rosette-forming cells (RFC). Culture of similar cells in the presence of puromycin for 1–6 hr before poly A:U did not significantly reduce the response. Continued culture of primed spleen cells in the presence of poly A:U, resulted in a decrease of RFC to background levels within an hour followed by an increase again 6 hr later. This later increase in RFC was inhibited by addition of puromycin to the culture medium.
The nonspecific stimulation by poly A:U of antibody production by primed spleen cells also was induced in vivo. Increases in splenic RFC were detectable 6 hr after intravenous injection of poly A:U alone, without antigen, into primed mice. The response peaked at 18 hr and had dissipated completely within 3 days. A second injection of poly A:U 24 hr or later after the first injection resulted in a second response, similar to the first with respect to kinetics and intensity. Rosette formation by poly A:U-stimulated cells could not be inhibited by mitotic poisons, but was inhibited by treatment of the cells with goat anti-mouse γ-globulin serum, suggesting that the antibody involved was a 7S γ-globulin.
The decrease in RFC induced by culture of primed cells for 1 hr in poly A:U paralleled a decrease in secondary responsiveness of the cells to antigen. This poly A:U-induced inhibition of secondary responsiveness could be reversed by suspending the treated cells in supernatant fluids derived from poly A:U-stimulated cultures. The reversal was specific in that supernatant fluids removed from bovine serum albumin (BSA)-primed cells by poly A:U did not stimulate the response of HGG-primed cells to HGG. However supernatant fluids from BSA-primed cells caused the production of anti-HGG RFC if BSA rather than HGG was used as triggering antigen. The active factor in the supernatant fluids appeared to be a 7S γ-globulin since activity was lost after 45 min incubation of the supernatant fluids in the presence of goat anti-mouse 7S γ-globulin serum.
THE LIFE-SPAN AND RECIRCULATION OF MARROW-DERIVED SMALL LYMPHOCYTES FROM THE RAT THORACIC DUCT
Authors: Howard Jonathan C. 
Published: June 2004

These experiments describe the preparation of pure marrow-derived lymphocyte suspensions from the thoracic duct of thymectomized, irradiated rats reconstituted with bone marrow cells. The majority of marrow-derived cells were small lymphocytes morphologically indistinguishable from small lymphocytes in thoracic duct lymph of normal donors.
Marrow-derived small lymphocytes (B lymphocytes) were a predominantly long-lived population; the frequency of short-lived B lymphocytes in the thoracic duct was not significantly higher than the frequency of short-lived small lymphocytes in normal lymph.
B lymphocytes transferred to normal recipients recirculated from blood to lymph. The first appearance of intravenously injected B lymphocytes in the thoracic duct was delayed relative to lymphocytes from normal donors and there was no clear cut modal recirculation time. Nevertheless their recirculation over a 48 hr period after transfusion was of the same order of magnitude as that of lymphocytes from normal donors.