bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vitro Induction of Tumor Specific Immunity
Authors: Burton Robert C. , Chism Stanley E. , Warner Noel L. 
Published: December 2022

Abstract
The 51Cr release cytotoxicity assay was used to evaluate whether self-reacting clones of T cells develop in vitro when normal spleen cells are cultured with irradiated syngeneic cells. This phenomenon has previously been described as autosensitization and has been thought to be due to reactivity against self-determinants. It was shown, however, in this present study that the autosensitization phenomenon differs qualitatively and quantitatively from specific immune induction by oncofetal antigens and tumor-associated antigens. A variety of tumor cell lines of different H-2 types are lysed by autosensitized cells, and the lysis appears to be nonspecific and not restricted to identity at the major histocompatibility complex (MHC). Induction of autosensitization follows the same kinetic pattern, and lysis is semilogarithmically related to effector cell to target ratio as in other systems. Analysis of the specificity of the phenomenon by competitive inhibition with tumor cells or congenic derived spleen cells did not, however, indicate any reactivity for self-MHC determinants, but rather showed that a wide range of culture tumor cells were all capable of inhibiting lysis. Since it was further shown that the level of autosensitization was markedly dependent on the batch of fetal calf serum, it is provisionally concluded that this phenomenon does not represent specific T cell activation to self-determinants, but rather reactivity against minor antigens in the system, possibly a cell-bound fetal calf serum component.
Immunosuppressive Properties of a Peptic Fragment of BSA
Authors: Muckerheide Annette , Pesce Amadeo J. , Michael J. Gabriel 
Published: December 2022

Abstract
The immunogenic properties of a peptic fragment of BSA were investigated. BSA was subjected to limited proteolysis by pepsin and the resulting fragments were separated on DEAE cellulose. The fragment under consideration, Fraction Ia (m.w. 8000 to 10,000), did not precipitate with anti-BSA serum but did inhibit the binding of specific antibody to labeled BSA, indicating the presence of determinants found on the native antigen. BDF1 mice immunized with Fraction Ia in A1(OH)3 gel or in complete Freund's adjuvant produced no significant antibody response as measured by passive cutaneous anaphylaxis (PCA) or by a modified Farr assay. The fragment elicited a PCA reaction in mouse skin sensitized with anti-BSA serum. Treatment of mice with single doses of Fraction Ia at various time intervals before immunization with BSA resulted in significant suppression of the formation of anti-BSA antibody. The conditions of suppression of the IgE response by the peptic fragment were studied in greater detail. Evidence is presented that such suppression can be attributed to the presence of specific T suppressor cells in our system.
Enhancement of C5̄6̄-Initiated Lysis by Cell-Bound C3 Fragments: Evidence for a Mechanism Independent of the Prior Binding of C5̄6̄ to C3b
Authors: Yamamoto Ken-Ichi , Lint Thomas F. , Gewurz Henry 
Published: December 2022

Abstract
Cell-bound C3b can reversibly bind C, activated complex of the fifth (C5) and sixth (C6) components of complement, and in this way potentiate C-initiated lysis by favoring the formation of C at the cell surface. We report here another way in which cell-bound C3 fragments can enhance C-initiated lysis, which involves C generated in the fluid phase rather than at the cell surface. Evidence for the involvement of fluid phase was obtained by use of dextran sulfate, which is known to inhibit the hemolysis of E mediated by fluid phase . Dextran sulfate strongly inhibited the formation of sites on cells bearing C4b and C3b (EAC4b3b) as well as on unmodified E when and C7 were added simultaneously to the cells. By contrast, dextran sulfate had virtually no effect on the reaction sequence involving the prior binding of C to C3b and subsequent formation of at the cell surface. Treatment of EAC4b3b with either anti-C3 Fab′ fragments or the C3b inactivator reduced but did not eliminate the enhancement of hemolysis, raising the possibilities that a C3 fragment(s) other than C3b also can enhance C-initiated lysis and/or that the enhancement is indirect without a requirement for an interaction between and the cell-bound C3 fragment itself.
Antibodies to Bacterial and Tumor-Derived Antigens in Sera from Normal Guinea Pigs
Authors: Brunda Michael J. , Minden Percy 
Published: December 2022

Abstract
Antibodies that react with radiolabeled antigens derived from guinea pig line-10 tumor cells and Mycobacterium bovis (BCG) were detected in sera from normal tumor-free strain-2 guinea pigs (NGPS). Binding by NGPS to the two antigens was inhibited by extracts of either line-10 cells or BCG. Binding by NGPS to the line-10 antigen was inhibited by a number of other bacterial extracts. NGPS was tested after absorption with a variety of cells including line-10, line-1, normal guinea pig spleen, normal adult and fetal liver cells. Results indicated that some of the antibodies in NGPS were directed to line-10-specific determinants. The specific stimulating antigen for these antibodies was not identified but because of the antigenic relationship between BCG, line-10 cells and other bacteria, antibodies to line-10-associated antigens might have been induced by exposure to environmental microorganisms.
Initiation of Bone Resorption by the Classical and Alternative C Pathways and Its Mediation by Prostaglandins
Authors: Sandberg Ann L. , Raisz Lawrence G. , Goodson J. Max , Simmons Hollis A. , Mergenhagen Stephan E. 
Published: December 2022

Abstract
Activation of C by immunoglobulins reactive with cell surface antigens stimulated synthesis of prostaglandin E and resultant release of 45Ca from organ cultures of fetal rat bones labeled in utero. Absorption of the C source (rabbit serum) with rat spleen cells or dilution of C abolished this activity which was, however, restored by addition of immunoglobulin preparations from sera of rabbits immunized with either rat erythrocytes or sonicated fetal rat bones. The active reconstitution factors were present in the 50% (NH4)2SO4 cut of the antisera and were eluted from Sephadex G-200 in both the 19S and 7S fractions and from DEAE cellulose in the IgG-containing fraction. The C-dependent resorption of bone by the F(ab′)2 fragments of the IgG antibody implicated a role for the alternative C pathway in this event. Complete inhibition of this biologic effect by indomethacin and detection of enhanced levels of prostaglandin E in the media of cultures containing antibody and C demonstrated a role for prostaglandins as mediators in the destruction of bone initiated by immune activation of C.
Echinococcus Granulosus: Identification of Subunits of the Major Antigens
Authors: Piantelli Mauro , Pozzuoli Roberto , Arru Efisio , Musiani Piero 
Published: December 2022

Abstract
This paper describes a procedure for obtaining the two “major” Echinococcus granulosus antigens (antigens 4 and 5) from sheep hydatid fluid. Purified antigen 4 (m.w. 400,000 and over) and antigen 5 (m.w. 150,000) were separated in order to identify molecular subunits of each. SDS 12.5% polyacrylamide gel electrophoresis of antigen 4 gave a single band for which a m.w. of 67,000 was calculated. When 5% 2-mercaptoethanol was added to the antigen 4 preparation, SDS 12.5% polyacrylamide gel electrophoresis gave two bands (m.w. 47,000 and 20,000). SDS 12.5% polyacrylamide electrophoresis of antigen 5, with or without 2-mercaptoethanol, gave at least three bands with m.w. ranging from 10,500 to 20,000. Low m.w. subunits of both antigens were eluted in a single peak from a preparatory SDS 7.5% acrylamide gel electrophoresis; these subunits were found to be immunogenic and antigenic.
Evidence for Cyclic GMP and Calcium Mediation of Lymphocyte Activation by Mitogens
Authors: Coffey Ronald G. , Hadden Elba M. , Hadden John W. 
Published: December 2022

Abstract
The results of 47 experiments indicate that the lectin mitogens, PHA and Con A, increase cyclic GMP (cGMP) levels in human peripheral blood lymphocytes and their incubation medium 2- to 9-fold within 10 min of stimulation. At concentrations supraoptimal for the induction of proliferation, Con A, but not PHA, induces progressive increases in cAMP and lesser increases in cGMP. Succinylated Con A (S-Con A) does not exhibit inhibition of proliferation up to concentrations of 250 µg/ml and correspondingly does not produce the cAMP increases observed with native Con A. PHA and both forms of Con A induce modest increases in cGMP in the absence of calcium and no increases in the presence of EGTA. After preexposure to Con A in the absence of calcium, the addition of calcium produces increases in cGMP. The data are consistent with the interpretation that mitogen-induced increases in lymphocyte cGMP are totally Ca2+-dependent, yet only in part dependent on extra-cellular Ca2+. The interpretation is confirmed with a divalent cation ionophore A23187, which was shown to induce lymphocyte proliferation in close association with Ca2+-dependent increases in cGMP and at higher concentrations to inhibit the mitogenic effects in association with Mg2+-dependent increases in cAMP. Dose-response curves for each agent showed that this capacity to increase cGMP levels was correlated with the optimal mitogenic concentration as determined by assay of DNA synthesis. The data are consistent with the postulate that cGMP participates in the positive aspects of mitogen action and that cAMP participates in the inhibitory aspects. It is concluded that coparticipation of cGMP and Ca2+ as essential mediators of the mitogenic signal is a sound hypothesis.
Characterization of Antigen-Binding Receptors in Vitro
Authors: Benfari Mary Jane F. , Cooperband Sidney R. , Moolten Frederick L. 
Published: December 2022

Abstract
We examined the kinetics and affinity of antigen binding in lymphoid populations in mice after immunization. There is increased binding capacity in lymphoid cells from animals that have undergone primary immunization. This increase would seem to be related to increased numbers of antigen-binding cells (rosette-forming cells). The serum antibody titers rise after the increasing binding capacity and numbers of BSA rosette-forming cells have increased. There is an increased amount of antigen bound per antigen-binding cell at certain times after immunization with two peaks in this capacity being demonstrable—one occurring at 4 days after immunization and the second occurring approximately 12 days after immunization and persisting for prolonged periods after that. With time, after immunization two separable peaks of increased antigen-binding cells become apparent, one very early (before Day 4) and one later (after Day 20 to 30). The affinity constants for antigen-binding cells have been measured and found to be high, and to increase with time after immunization. It appears that the heterogeneity of the affinity constants for antigen-binding cells is high early in immunity and becomes more homogeneous with time after immunization.
Activation of T and B Lymphocytes in Vitro
Authors: Eshhar Zelig , Armerding Dieter , Waks Tova , Katz David H. 
Published: December 2022

Abstract
The biologic and metabolic conditions required for optimal production of a nonantigen-specific biologically active factor termed allogeneic effect factor (AEF) have been explored in greater depth. AEF is produced in mixed lymphocyte cultures (MLC) of in vivo alloantigen-activated T cells (ATC) and the respective target cells. In these studies, we describe conditions for production of AEF in serum-free media supplemented with appropriate concentrations of 2-mercaptoethanol, Ficoll, or gelatin. Analysis of the cellular components required for AEF production revealed that AEF is not produced by macrophages nor are macrophages required for optimal production of AEF in vitro. The production of AEF requires the participation of T cells of the Ly-1+, Ly-2, 3- phenotype in the effector cell population and target cells of appropriate specificity differences determined by H-2 haplotype; Mls locus differences are neither essential nor effective in inducing AEF production in this secondary MLC system.
Investigation of the possible contribution of target cell products to the active components of AEF involved the use of glutaraldehyde-fixed normal spleen cells of lipopolysaccharide-induced blasts as stimulators in the MLC. Although it was found that such fixed cells could serve as effective stimulators of AEF production, the finding that 7 to 10% of radiolabeled surface membrane proteins were shed from target cells despite glutaraldehyde fixation precluded a definitive conclusion on the role of target cell products in AEF activity. Finally, metabolic inhibitors were used to explore the metabolic processes required of the participating cells; such studies demonstrated that neither proliferation nor DNA synthesis is required for generation of active AEF, whereas protein synthesis, glycolysis, and electron transfer are required.
Lytic Activity of C5̄‑9̄ Complexes for Erythrocytes from the Species Other Than Sheep: C9 Rather Than C8-Dependent Variation in Lytic Activity
Authors: Yamamoto Ken-Ichi 
Published: December 2022

Abstract
With the reactive lysis system, a form of hemolysis mediated solely by the late-acting complement components (C, C7, C8, and C9), guinea pig C9 (C9gp) was found to be very inefficient in inducing the lysis of guinea pig and mouse erythrocytes bearing human C. By contrast, C9gp could efficiently induce the lysis of sheep and goat erythrocytes bearing human C. By contrast, C9gp could efficiently induce the lysis of sheep and goat erythrocytes bearing human C5-8. Human C9 was efficient in the lysis of erythrocytes from the species mentioned above. Further study showed: 1) the observed inefficiency in the lysis of guinea pig erythrocytes was not due to incompatibility between human C7 or C8 and C9gp; 2) C9gp could efficiently bind to guinea pig erythrocytes bearing human C but was inactive in the subsequent lytic process. The present finding emphasizes a role for C9 in complement-mediated membrane damage which may not be a simple effector function of C8 action.
Cytotoxic Activity of Human Lymphocytes: Quantitative Analysis of T Cell and K Cell Cytotoxicity, Revealing Enzyme-Like Kinetics
Authors: Zeijlemaker Wim P. , van Oers Rien H. J. , de Goede Ruud E. Y. , Schellekens Peter Th.A. 
Published: December 2022

Abstract
The mechanism of action of human cytotoxic lymphocytes was studied in two systems: T cell cytotoxicity in cell-mediated lympholysis (CML) and K cell cytotoxicity in antibody-dependent lymphocytotoxicity (ADL). The mechanisms resemble that of an enzyme, if the effector cells are regarded as enzyme and the target cells as substrate. On the basis of a kinetic analysis it was shown that the experimental data are compatible with a simple rate equation, which allows the definition of three constants: p, representing the maximal killing rate of the effector cell suspension (at target →∞); q, representing the maximal lysis of the target cells (at effector →∞); K which represents the Michaelis constant (i.e, the target cell number giving ½ Vmax), when extrapolated to effector = 0. The constant K may be taken to reflect the affinity between effector and target cells.
Furthermore, for the ADL system the influence of the effector cell concentration on Km was due not to the addition of inert cells but rather to the presence of cells that can bind but not kill. Finally, it was shown that in the ADL a K cell can recycle, i.e., kill more than one target cell.
On the basis of these results, experimental conditions are proposed for optimal measurement of cellular cytotoxicity.
The Demonstration of Subtype (D or Y)-Specific Determinants on the Surface of the Presumed Hepatitis B Virus
Authors: Hess G. , Shih J. W-K. , Kaplan P. M. , Gerin J. L. 
Published: December 2022

Abstract
Dane particles isolated from the sera of HBsAg/ad and HBsAg/ay carriers were reacted with monospecific antibodies to the d and y subtype-specific determinants of HBsAg/. Dane particles from HBsAg/ad sera expressed the d determinant on their surfaces and those from HBsAg/ay sera contained the y specificity. Both complete (DNA-P and HBcAg) and defective (HBcAg alone) Dane particles expressed the subtype-specific determinants.
Effect of Cyclophosphamide on Interstitial Nephritis and Tubule Cell Proliferation in NZB/NZW Mice
Authors: Hurd Eric R. 
Published: December 2022

Abstract
The effect of cyclophosphamide on renal interstitial mononuclear cell infiltration and renal tubule cell (TC) proliferation has been examined in (NZB × NZW)F1 hybrid (B/W) and control mice. TC proliferation was measured by tritiated thymidine (3HTdr) injection, autoradiographic examination of kidney sections, and enumeration of labeled tubular cells. Cyclophosphamide administered 2 months before sacrifice virtually obliterated interstitial infiltration and significantly decreased tubule cell proliferation at 3, 5, 7, 9, and 12 months of age.
Hydrocortisone Affects Tumor Growth by Eliminating Precursors of Suppressor Cells
Authors: Schechter Bilha , Feldman Michael 
Published: December 2022

Abstract
Suppressor lymphocytes responsible for the suppression of anti-tumor immune response were previously demonstrated in spleens of C57BL mice carrying the syngeneic Lewis lung carcinoma (3LL). Based upon earlier observations on the inactivating effect of hydrocortisone (HC) on precursors of suppressor lymphocytes, we have now studied the effect of the steroid on the anti-tumor cellular immune response and on tumor development in 3LL-bearing mice. Mice were given a single injection of HC before, together with, or after the inoculation of 3LL tumor cells. Tumor development and mouse mortality were delayed when HC was administered after tumor inoculation. The highest delay was observed when the steroid was injected to the mice 3 to 5 days after the tumor cells. HC-resistant spleen cells (15 to 30% of the total number of cells) obtained from such tumor-bearing mice (TBM) 2 or 3 days after HC treatment enhanced tumor development significantly more than cells from untreated TBM, when transferred together with tumor cells into syngeneic recipients. However, this enhancing activity rapidly disappeared upon spleen regeneration. Spleen cells obtained 7 to 14 days after HC injection manifested a protective activity against tumor growth. These results suggest that HC affects the balance between lymphocyte subpopulations which participate in either the rejection or the enhancement of the tumor. HC-resistant spleen cells recovered from the spleens of TBM shortly after HC treatment seem to be enriched for preformed mature suppressor cells, but are deficient for their precursors. This deficiency, which is transient due to thymus and spleen regeneration, is later on expressed in an increased cytotoxic response against the tumor.
The Expression of Ia Antigens on Immunocompetent Cells in the Guinea Pig
Authors: Yamashita Uki , Shevach Ethan M. 
Published: December 2022

Abstract
Only 15 to 25% of purified oil-induced guinea pig macrophages could be lysed by treatment with anti-Ia serum and C. Those cells remaining alive after treatment were not damaged and were metabolically active since they readily phagocytized latex beads. However, the “Ia-negative” macrophages were markedly deficient in their ability to present protein antigens to immune T lymphocytes and to function as stimulator cells when mixed with allogeneic T cells in the mixed leukocyte reaction. It thus appears that Ia antigens are expressed on a subpopulation of macrophages and that this subpopulation plays a critical role in the activation of T cell proliferation to soluble protein antigens and to alloantigens.
Cleavage of Human C5 by Trypsin: Characterization of the Digestion Products by Gel Electrophoresis
Authors: Minta Joe O. , Man Doreen P. 
Published: December 2022

Abstract
Human C5 is composed of two nonidentical polypeptide chains, α and β (m.w. 130,000 and 80,000, respectively) linked together by disulfide bonds and noncovalent forces.
Cleavage of C5 by trypsin was restricted to the α-chain and resulted in the generation of major fragments with increased anodic mobilities. Limited digestion of C5 by trypsin (substrate to enzyme ratio 10:1 w/w at 37°C for 1 min) resulted in the release of a small terminal α-chain peptide (α1, m.w. 15,000) probably analogous to C5a, from a large fragment, C5b (m.w. 195,000) composed of an intact β-chain disulfide linked to an α-chain that has a lower m.w. (α′ 115,000). Further digestion (37°C, 5 min) resulted in cleavage of the α-chain at multiple sites with the production of three peptides from the α′-chain (α2I, 23,500; α2II 15,700 and α2III 10,200) and a residual fragment, C5c (m.w. 144,000). The α1 and α2 peptides are not covalently linked to the β-chain nor to one another. The C5c fragment on the other hand is composed of small peptides of the α′c chain (α3 14,000; α4I 9,000; α4II 11,000; α5 23,000 to 30,000) which are linked to the β-chain and also probably to one another by covalent bonds. Secondary cleavage occurred upon prolonged digestion with trypsin (37°C, 20 min), and this resulted in the progressive erosion of the α′c peptides and the conversion of C5c to smaller C5c-like species.
Demonstration of Activation of B Lymphocytes in New Zealand Black Mice at Birth by an Immunoradiometric Assay for Murine IgM
Authors: Moutsopoulos Haralampos M. , Boehm-Truitt Marilyn , Kassan Stuart S. , Chused Thomas M. 
Published: December 2022

Abstract
We have developed a highly specific and sensitive “two-site” immunoradiometric assay for murine IgM in which antigen bound to immobilized antibody reacts with affinity-purified radiolabeled antibody. We utilized the sensitivity of this assay to study the rate of IgM secretion in short-term cultures by spleen cells from the autoimmune strains, New Zealand Black (NZB) and New Zealand Black by New Zealand White F1 hybrid (BW), and from normal (C57BL/6, DBA/2, NZW) mice. The temperature dependence of IgM secretion in short-term cultures, its pentameric structure, and the similar viability of NZB and normal strain spleen cells indicate that active IgM synthesis is being measured. We observed that the splenic B lymphocytes of NZB and BW mice, in contrast to normal strains, produce IgM in vitro at birth. By 6 to 8 weeks of age NZB and BW spleen cells produce 40 times more IgM than spleen cells from normal strains of mice. The IgM produced in vitro by splenic lymphocytes from NZB and BW mice is not absorbed by syngeneic or allogeneic thymocytes or erythrocytes.
Reconstitution of C1 in Native, Proenzyme from and Its Use in a Quantitative C1 Activation Test
Authors: Cooper Neil R. , Ziccardi Robert J. 
Published: December 2022

Abstract
C1 was reconstituted in macromolecular proenzyme, nonactivated form by incubation of highly purified C1q, C1r, and 125I-C1s together in the presence of calcium. C1 reformed in this manner had an equimolar ratio of C1 subcomponents, as is found in serum, and sedimented in sucrose density gradients with the 16S rate characteristic of C1 in serum. Reconstituted C1 was activatable as shown by cleavage of the 87,000 dalton polypeptide chain of C1s into disulfide linked subunits of 59,000 and 28,000 daltons, respectively, after incubation with aggregated IgG. The extent of activation may be quantitated. Reformed activatable proenzyme C1 can be used to quantitatively assess the C1-activating properties of various substances in addition to its use in the analysis of the C1 activation process.