bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is Factor D of the Alternative Pathway a Fragment of Thrombin?
Authors: Davis A. E. , Rosenberg R. D. , Fenton J. W. , Bing D. H. , Rosen F. S. , Alper C. A. 
Published: January 2023

Abstract
Properdin factor D (GBGase, C3Pase) is a 25,000 dalton protease required for alternative pathway activation. After isoelectric focussing of normal human serum (NHS) in polyacrylamide gel, an agar gel overlay containing 1.7% guinea pig erythrocytes and 10% NHS in 0.05 M barbital buffer with 1 mM mg++ and 5 mM EGTA developed lysis bands for C3, factor B and one other protein with a more basic isoelectric point. The latter (but not bands of C3 or B) is also produced in an overlay containing factor D-depleted serum instead of NHS (Martin et al.). In both these assays, purified human α, β/γ, and autocatalyzed thrombin (T) produced lysis bands corresponding to protein distribution. The major band of autocatalyzed, but no other T, coincided with factor D. Incubation of β/γT in NHS resulted in no noticeable loss of intensity of the lytic bands.
Activation of the Alternative Complement Pathway by Escherichia Coli: Resistance of Bound C3b to Inactivation by C3bINA and β1H
Authors: Fearon D. T. 
Published: January 2023

Abstract
The surfaces of activators of the alternative pathway, such as zymosan and rabbit erythrocytes, provide sites which protect bound C3b from inactivation by C3b inactivator (C3bINA) and β1H, and P,C3b,Bb from decay-dissociation by β1H. This circumstance permits surface-associated amplified generation and deposition of C3b. The capacity of a bacterial surface, if analogous to zymosan and rabbit erythrocytes, to protect and thereby accumulate increasing amounts of C3b by local circumvention of the regulatory proteins would be compatible with a unique role of the alternative pathway in host defense. The susceptibility of C3b bound to Escherichia coli to C3bINA was compared with that of C3b bound to the nonactivator, sheep erythrocytes, in the state, EAC4b,3b. E. coli W3110, killed by heating at 60°C for 60 min, activated the alternative pathway in human serum diluted 1:5 in GVB containing 2 mM Mg++ and 8 mM EGTA as demonstrated by 82% C3 and 87% B consumption.
Purification and Characterization of a Mouse Serum Protein with Specific Binding Affinity for C4 (Ss protein)
Authors: Ferreira Arturo , Weisz-Carrington Paul , Gigli Irma , Nussenzweig Victor 
Published: January 2023

Abstract
A new protein named Ss-bp, or C4-bp, with specific binding affinity for activated C4 has been found in mouse serum. Ss-bp is a heat-stable (60° C, 1 hr) β-globulin with a sedimentation coefficient of 10S. Ss and Ss-bp are separated by filtration of EDTA-plasma in Sephadex G-200. However, in serum, Ss-bp binds tightly to Ss and the complex is found in the excluded volume of the column. After electrophoresis in agarose at pH 8.6, the Ss-bp/Ss complex moves faster toward the anode than either protein alone. For this reason Ss-bp may appear to be polymorphic in serum of mice with high levels of C4 (Ss-H) versus those with low levels of C4 (Ss-L) (Ferreira, Takahashi and Nussenzweig, J. Exp. Med., in press).
Ss-bp levels are higher in serum of males (160 µg/ml) than in female mice (60 µg/ml). As in the case of other mouse C components (C4, C5), the concentration of Ss-bp in serum is markedly influenced by testosterone.
The Structural Events Associated with the Attachment of Complement Components to Cell Membranes in Reactive Lysis
Authors: Dourmashkin R. R. 
Published: January 2023

Abstract
The events occurring at the cell membrane during reactive lysis were studied by electron microscopy, using purified complement components (generously donated by Drs. W. Kolb, E. Podack and H. J. Müller-Eberhard, Scripps Clinic). At the stage, no particles were seen attached to the membrane after preparation for E.M. At the stage, a foliaceous particle was seen attached to the membrane surface, with a narrow stalk and two to three arms extending outward. At the stage, the particles appeared larger and possessed up to six arms. None of these stages showed any lesions previously described as “complement holes.” However, the stage showed many typical complement lesions, presumably due to the rearrangement of the structure of the particles.
The lesions in profile appeared to show channels that penetrated all or part of the thickness of the cell membrane; however, such observations must be interpreted with caution, as the relation of the E.M. negative staining image of the membrane to the biologic structure has not been clarified.
Properties of the Early Classical Complement System of Mice
Authors: Goldman John N. , Goldman Margaret B. 
Published: January 2023

Abstract
Mouse serum and EDTA plasma were subjected to low ionicity precipitation, ion exchange chromatography and gel filtration in an attempt to separate and purify C1, C4 and C2. Although they could be obtained free of many other serum proteins these three components could not be significantly separated from one another using a wide variety of ion exchange resins and gels and conditions of elution. C1, C4 and C2 eluted from Sephadex G-200 in buffers containing EDTA with an apparent molecular weight of approximately 150,000 and in buffers containing Ca++ and Mg++ with an apparent molecular weight of over 500,000. Cell bound activity can be formed by incubation of EA in mouse serum as indicated by the lysis of these cells upon the later addition of guinea pig serum in EDTA. Incubation of EA in mouse serum followed by incubation in buffers containing 10 mM EDTA resulted in a rapid loss of all detectable C1, C4 and C2 functional activities.
The Induction of Macrophage Spreading by Factor B of the Properdin System
Authors: Götze O. , Bianco C. , Cohn Z. A. 
Published: January 2023

Abstract
The previously reported complement-dependent spreading of freshly explanted mouse peritoneal macrophages was further analyzed. Whereas the screening of components of the classical pathway did not reveal any activity, mixtures of human Factors B, D̄ and C3b (after incubation) induced spreading in 50–80% of 5 × 104 glass-attached macrophages within 60–120 min. In order to define the active factor(s) or their fragments 125I-labeled B was added to fresh human serum which was then activated for 60 min, 37° using 5 mg inulin/ml serum. After fractionation of the serum on DEAE- and CM-cellulose and on Sephadex G150 columns spreading activity was found in fractions containing the activated form of B (Bb) and closely followed the distribution of 125I-Bb in the columns' eluates. Fractions containing C3b or Ba lacked activity. Highly purified Bb was prepared from purified B by incubation with D̄, and C3b. Bb was then separated from D̄, Ba and C3b by DEAE-cellulose chromatography.
Differential Patterns of C3b Receptor Expression on Guinea Pig Macrophages
Authors: Koopman W. J. , Wahl L. M. , Sandberg A. L. , Mergenhagen S. E. 
Published: January 2023

Abstract
Initial investigations revealed that the expression of C3b receptors on macrophages was markedly influenced by the manner in which the cells were obtained. Resident (wash-out), glycogen-induced and oil-induced guinea pig peritoneal cells were harvested and adherent cell monolayers were cultured in a serum-free Dulbecco's medium at equivalent cell concentrations. Monolayers contained 90 to 95% macrophages as assessed by nonspecific esterase activity and latex ingestion. Macrophage membrane C3b receptors were detected by rosetting with EIgMC143bgp indicator cells (100 IgM sites/indicator cell; 20 RBC/macrophage) at varying times after initiation of culture. Marked differences in C3b receptor expression were observed among the three macrophage populations. 81%±4% of resident peritoneal macrophages rosetted with EIGMC143bgp indicator cells at the initiation of culture and minimal decline in C3b receptor expression occurred at 16 hr of culture (70%±5% rosettes). In contrast, 35%±8% of oil-induced peritoneal macrophages rosetted initially and by 16 hr only 15%±9% of these cells formed rosettes with C3b-bearing indicator cells.
Monocyte Complement Stimulator (M.C.S.): A T Lymphocyte Product Capable of Stimulating Production of the Second Complement Component (C2)
Authors: Littman Bruce H. , Ruddy Shaun 
Published: January 2023

Abstract
We have previously reported that the production of the second complement component (C2) by human monocytes can be stimulated by co-culture with lymphocytes and antigen or with lymphokine-rich culture supernates. Using lymphocyte subpopulations separated on the basis of rosetting with sheep erythrocytes (T-lymphocytes), we now report that only cultures composed of antigen-stimulated monocytes and T lymphocytes could produce this lymphokine activity. Macrophage migration inhibitory factor (M.I.F.) was also present in this supernate. Although antigen-stimulated B lymphocytes (rosette-negative lymphocytes), B lymphocytes with monocytes, monocytes only, and T lymphocytes only could not produce this lymphokine activity, supernate of antigen-stimulated B lymphocytes and monocytes did contain M.I.F., indicating that molecules with this activity are not necessarily identical with those responsible for stimulating C2 synthesis by monocytes.
Further, Sephadex G-100 gel filtration of supernates from antigen-stimulated lymphocyte cultures resulted in fractions also capable of stimulating monocytes to increase their C2 production.
Normal and Chronic Lymphocytic Leukemia Lymphocytes As Targets for Human Complement
Authors: Logue G. L. , Huang A. T. 
Published: January 2023

Abstract
Human lymphocytes are resistant to cytolytic effects of human complement in vitro. In order to study this phenomenon, the amount of human third component (C3) bound to lymphocytes from normal subjects and patients with chronic lymphocytic leukemia (CLL) was determined when complement was activated by reacting lymphocytes with anti-I antibody, anti-HLA-2 antisera, and rabbit anti-human lymphocyte antisera. C3 was quantitated by an anti-C3 consumption assay. Human C3 was bound to both normal and CLL lymphocytes in a dose-response fashion when the cells were exposed to human serum and the anti-lymphocyte antibodies. No quantitative differences were observed in binding of C3 to normal and CLL lymphocytes. Cytolytic effects of complement activation were measured by cell counting, dye exclusion, 51Cr release, release of 3H-thymidine labeled DNA, and the ability of the cells to incorporate 3H-thymidine and 3H-uridine into DNA and RNA.
A Role for IgG in the Activation of the Human Alternative Pathway by Rabbit Erythrocytes
Authors: Nelson Ben , Ruddy Shaun 
Published: January 2023

Abstract
A serum factor which participates in the early steps of the lysis of rabbit erythrocytes (E) by human serum in Mg-EDTA has been partially characterized. Normal human serum (NHS) when adsorbed with rabbit E or stromata at 0°C in the absence of divalent cations, lost 35% of its hemolytic activity against fresh rabbit E. The feedback loop activity (B, D, P) of the adsorbed serum was intact. The lost hemolytic activity was restored with a pH 3.4 eluate from the adsorbed stromata; the activity in the eluate has been termed “0° factor E.”
When 0° factor E was added to serum depleted of 0° factor E by prior absorption with rabbit E, a linear dose response was obtained which was concave to the abscissa, indicating that a single activity was being added. The activity was unaffected by heating to 56°C for 30 min and had an apparent molecular weight of 700,000 on Sepharose 4B gel filtration.
Modulation of the Alternative Pathway in Dilute Whole Serum by Introduction of Purified Components and Control Proteins
Authors: Nydegger U. , Fearon D. T. , Austen K. F. 
Published: January 2023

Abstract
Activators of the alternative pathway of complement such as zymosan, rabbit erythrocytes, and heat-killed E. coli protect bound C3b from C3bINA and P, C3b, Bb from decay-dissociation by β1H, thereby amplifying C3b generation and deposition. The capacity of purified components and control proteins to modulate alternative pathway activation by zymosan and rabbit erythrocytes (Er) was assessed in dilute C2-deficient human serum.
Zymosan-induced inactivation of C3 and B was determined at different intervals after 100 µg of zymosan were added to 150 µl of serum diluted 1:6 in VBS++. The mean inactivation of C3 and B at 45 minutes was 61 ± 5.4% (±1 SD) and 62 ± 5.7%, respectively. Various amounts of the control proteins were added to the serum to determine the increase over endogenous concentrations necessary to inhibit 50% of the zymosan effect. Increases of C3bINA by 43% and of β1H by 25% inhibited 50% of zymosan-induced inactivation of C3.
Antibody Responses to a T Cell Dependent Antigen in C4 Deficiency
Authors: Ochs Hans D. , Jackson Charles G. , Frank Michael M. , Hosea Stephen W. , Wedgwood Ralph J. 
Published: January 2023

Abstract
Complete absence of the fourth component of complement has been described in man and in guinea pigs. Recently, a close linkage between the gene(s) controlling synthesis of C4 and the major histocompatibility complex has been demonstrated in man as well as in the guinea pig.
Because of a possible relationship between immune responses and the complement system, we have studied antibody responses to a T cell dependent antigen in a patient and in guinea pigs with C4 deficiency. Bacteriophage Φχ 174, given intravenously, was cleared within one week after primary injection, similar to normal controls. The primary antibody response was markedly suppressed and shortened: in normal controls, antibody titers (mean Kv &gt; 8) persisted for over 4 weeks; in C4 deficiency, antibody (peak titer &lt; 1) disappeared 2–3 weeks following immunization. In the normal control population, a second injection of antigen resulted in a rapid rise of antibody (Kv &gt; 100) and transition from IgM to IgG.
Complement Cleavage Products in Inflammatory Exudates from Patients with Periodontal Diseases
Authors: Schenkein Harvey A. , Genco Robert J. 
Published: January 2023

Abstract
Periodontal diseases are characterized by an inflammatory exudate termed gingival fluid (GF). We have examined selected complement components for cleavage products in GF from patients with periodontitis and the less common disease, periodontosis. We hope to establish an objective criterion for diagnosis as well as to provide information on the mechanisms involved in producing periodontal inflammation.
GF samples (2 µl) were collected from 18 patients diagnosed as having severe periodontitis and blood samples were collected simultaneously. Serum and GF were stored at -76°C until assayed. Protein concentrations were measured by single radial immunodiffusion for nine plasma proteins, including C3, C4, and Factor B. An antiserum to C3 specific for the B determinant was utilized. It was found that GF contained only 20% of the a-C3 (B determinant) reactive material found in serum, while all other proteins measured were at levels 70 to 80% of that in serum.
Stimulation of Synthesis and Release of Lipids in Tumor Cells Under Attack by Antibody Plus Complement
Authors: Schlager Seymour I. , Ohanian Sarkis H. , Borsos Tibor 
Published: January 2023

Abstract
Resistance to antibody-complement- (Ab-C) mediated killing of guinea pig hepatoma cells (line-1 and line-10) correlates with the ability of the cells to synthesize lipids, but not DNA, RNA, protein, or complex carbohydrate. We therefore studied the synthesis and release of macromolecules (especially lipids) by tumor cells under attack by Ab plus C.
Ab-sensitized tumor cells (TA) incorporated increased amounts of acetate, glycerol, or fatty acids into complex lipids compared to control cells within 5 to 10 min after the addition of guinea pig C (GPC) to the cells (TAC). TA, TC, or TAΔC (Ab plus heat-inactivated GPC) did not show this effect. No enhancement of DNA, RNA, or protein synthesis in TAC as compared with control cells was noted. Line-1 cells, which are killed by GPC when sensitized with excess anti-Forssman Ab (TAxs), demonstrated enhanced lipid synthesis within 1 to 3 min after the addition of GPC to TAxs, before measurable killing of the cells had occurred.
Interaction of the First Component of Complement in Platelet Adhesion and Aggregation Induced by Collagen and Aggregated IgG
Authors: Wautier J. L. , Souchon H. , Reid K. B. M. , Peltier A. P. , Caen J. P. 
Published: January 2023

Abstract
Pure C1 subcomponents (C1q, C1r, C1s) and fragments were obtained by limited proteolysis with collagenase and pepsin. The fragments prepared with pepsin contained the collagen-like region of C1q whereas the collagenase-treated C1q had lost its collagen portion.
The different C1 subcomponents or fragment of C1q were tested for their effect on human platelets and on collagen-induced aggregation and adhesion of gel-filtered platelets. The collagenase-treated C1q was without effect in platelet collagen interaction.
The pepsin-derived fragment of C1q containing the collagen-like region inhibited platelet aggregation and adhesion to collagen. The preincubation of C1s with collagen inhibited platelet adhesion and aggregation. Studies on platelet aggregation induced by aggregated IgG showed that the complete molecule of C1q is necessary for the reaction.
The results suggest that the collagen-like region of C1q reacts with the platelet, and possibly with platelet-associated C1s or a structure similar to C1s.
Stability of DNA/Anti-DNA Complexes
Authors: Taylor Ronald P. , Weber Daniel , Broccoli Anthony V. , Winfield John B. 
Published: January 2023

Abstract
Antigenic specificity, concentration in serum, and binding avidity of different types of antibodies to DNA all contribute to the nature of circulating DNA/anti-DNA complexes in systemic lupus erythematosus (SLE), and thereby influence the potential of such complexes for tissue injury in this disorder. With highly purified single(s) and double(d) stranded 3H-DNA prepared from Escherichia coli, the rate of dissociation of DNA/anti-DNA complexes in the presence of excess unlabeled DNA was studied as a function of temperature and DNA conformation. At cold temperatures dissociation of complexes of antibody and ssDNA or dsDNA was slow and did not reach equilibrium. At 37°C “off rates” for ssDNA/antibody complexes generally were rapid, dissociation being complete within 1 hr. dsDNA/antibody complexes, on the other hand, were much more stable at higher temperatures than those formed with ssDNA. With many SLE sera, the majority of dsDNA remained bound to antibody after 24 hr of incubation with a large excess of unlabeled DNA. Kinetic studies of this type were compared with binding isotherms as methods of obtaining information concerning binding avidities of antibody for dsDNA and ssDNA.
The implications of these findings are discussed with regard to i) the pathogenicity of dsDNA/anti-DNA complexes, and ii) the difficulty of estimating binding avidity in multivalent antigen, antibody systems.
Damage to Schistosomula of Schistosoma Mansoni Induced Directly by Eosinophil Major Basic Protein
Authors: Butterworth Anthony E. , Wassom Donald L. , Gleich Gerald J. , Loegering David A. , David John R. 
Published: January 2023

Abstract
Major basic protein (MBP) from both human and guinea pig eosinophils has been found to damage schistosomula of Schistosoma mansoni at concentrations as low as 2 × 10-5 M. This damage can be detected both by light microscopy and by measurement of release of 51Cr from labeled larvae. Damage is attributable in part to the basic properties of the molecule, since some other cations of comparable molecular weight, such as protamine and polyarginine, have comparable effects at equimolar concentrations. Other cations, however, fail to mediate damage, indicating that simply the possession of a positive charge is a necessary but insufficient prerequisite. The action of MBP is not selective, since mammalian target cells can also be damaged. Damage induced by MBP is associated with uptake of the material onto the parasite's surface, and both uptake and damage can be blocked by heparin.
In addition, it has been found that MBP is released during the antibody-dependent reaction between human eosinophils and schistosomula, and can be detected both on the surface of the organism and free in small quantities in the supernatant. Damage mediated directly by eosinophils is not inhibitable by heparin, suggesting that the effect of eosinophils is attributable to the local release of high concentrations of MBP into a sequestered site adjacent to the parasite surface, rather than to a generalized release into the supernatant.
These findings suggest that release of MBP may represent a major mechanism of eosinophil-mediated damage to schistosomula and, since MBP is uniquely associated in high quantities with the eosinophil, these results provide a partial explanation for the selective action of eosinophils on antibody-coated schistosomula.
Functional Studies on Lymphocytes in Adult Human Bone Marrow
Authors: de Gast Gÿsbert C. , Platts-Mills Thomas A. E. 
Published: January 2023

Abstract
Bone marrow (BM) was obtained from rib sections removed during thoracotomy on 10 patients (mean age 45 years) with a primary lung tumor. A linear sucrose-serum density gradient was used to fractionate the nucleated bone marrow cells. The pellet fraction, which contained only a few lymphocytes but nearly all the morphologic plasma cells, showed spontaneous IgG and IgM production. The upper fraction (5 to 8% sucrose), comprising 82% lymphoid cells (24.2% T cells and 14.0% B cells (SmIg+ve cells)) showed no spontaneous Ig production, but in five cases produced Ig when stimulated with Pokeweed mitogen (PWM). After T/non-T cell separation of this lymphocyte rich (upper) fraction, the BM-non-T cells produced little or no Ig on their own even when they were stimulated with PWM. However, these cells produced IgM (mean 0.57 μg/ml) and/or IgG (mean 1.69 μg/ml) when cultured with mitomycin-C-treated allogeneic peripheral blood T cells (PB-Tm) and PWM. Parallel cultures of similarly separated PB-non T cells in the presence of PWM and the same PB-Tm produced significantly more Ig (mean IgM 6.02 μg/ml; mean IgG 5.33 μg/ml). When BM-T cells were cultured with PB-non-T cells they appeared to give very poor help for Ig production (IgM mean 0.07 μg/ml, IgG mean 0.27 μg/ml). The results show that bone marrow lymphocytes as judged by Ig production are functionally poor compared with peripheral blood lymphocytes. It seems possible that at least part of the BM-B cells are immature and not able to respond to PWM. The T cells in bone marrow may also be immature or may belong to T cell subpopulations other than helper T cells.