bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the Molecular Basis for C1̄s Action and Comparison of C1̄s with Other Tryptic Proteases
Authors: Roman D. P. , Andrews J. M. , Bing D. H. , Cory M. 
Published: December 2022

Abstract
One of the principal problems in current complement research is our understanding of the molecular basis of complement action. In order to probe the molecular biology and specificity of the serine protease, C1̄s, it was compared with three human proteases. The proteases examined were the serum enzymes C71̄s, thrombin and plasmin, and the pancreatic enzyme trypsin. An assay procedure using the simple synthetic chromophoric esters N-carbobenzoxy-l-tyrosine-p-nitrophenyl ester and N-carbobenzoxy-l-lysine-p-nitrophenyl ester as substrates was developed. A group of over 20 mono- and di-substituted benzamidines, known as competitive inhibitors of bovine tryptic enzymes, were used to probe the active sites.
The inhibition constants obtained were correlated with factors describing the lipophilicity and electronic character of the inhibitors using multiparameter regression analysis. Marked similarities were noted between C1̄s and the other enzymes. The difference between the enzymes with respect to their inhibition profiles can be interpreted on a molecular basis to account for some of the specificity shown by these enzymes.
Stimulation of Prostaglandin Synthesis with Resultant Bone Resorption by the Classical and Alternative C Pathways
Authors: Sandberg Ann L. , Raisz Lawrence G. , Goodson J. Max , Mergenhagen Stephan E. 
Published: December 2022

Abstract
In vitro studies suggest that C activation may contribute to the bone loss associated wath certain inflammatory conditions. Rat fetal long bones (radii and ulnae), prelabeled in utero with 45Ca, were cultured in the presence of rabbit serum either containing or lacking C activity, and resorption was detected by the efflux of 45Ca into the media. In the present studies, serum concentrations were chosen which did not themselves support bone destruction since previous investigations demonstrated resorption in the presence of high concentrations of C sufficient serum. However, in these limited serum cultures, resorption could be initiated by the addition of activators of either the classical or alternative C pathways. Rabbit anti-rat erythrocyte IgG, obtained by DEAE-cellulose chromatography, and 19S and 7S fractions, obtained by Sephadex G-200 column chromatography, initiated resorption in the presence of C, whereas, non-tissue-related immune complexes were inactive.
Mechanism of Action of the Chemotactic Factor Inactivator of Human Serum
Authors: Ward P. A. , Ormrod J. C. , Ozols J. 
Published: December 2022

Abstract
The chemotactic factor inactivator (CFI) irreversibly inhibits the leukotactic activity of complement C3 and C5 fragments, and the activity of leukotactic factors produced in bacterial cultures. In order to elucidate the mechanism of inhibition, CFI was purified from human serum and its interaction with synthetic peptides investigated. Kininase activity was present in all CFI preparations, as revealed by bioassay of bradykinin which had been pretreated with CFI. Amino acid analysis of the inactivated bradykinin preparations revealed the presence of free arginine, proline, phenylalaninine, glycine, and serum. Incubation of CFI with the highly active chemotactic peptide Met-Leu-Phe or with its amide derivative, resulted in a concomitant loss of the leukotactic activity and the simultaneous appearance of the corresponding free amino acids. The highly potent chemotactic peptide formyl-Met-Leu-Phe, however, was completely resistant to CFI hydrolysis, as assessed by bioassay (chemotaxis) and amino acid analysis methods.
C3bINA Accelerator: A Serum Cofactor for C3b Inactivator Necessary for the Full Expression of Its Activity
Authors: Whaley Keith , Ruddy Shaun 
Published: December 2022

Abstract
C3b inactivator (C3bINA) may be measured as activity in a hemolytic assay or as protein by radial immunodiffusion. The observation that purified C3bINA has fewer units of activity per microgram or C3bINA protein than C3bINA in unfractionated serum is accounted for by the presence in serum of a cofactor which accelerates C3bINA-dependent C3 inactivation.
Sephadex G-200 chromatography of human serum yields a single peak of C3b-inactivating activity coincident with immunochemically detectable C3bINA. A second area of C3b-inactivating activity appears on the descending limb of the 19S peak if fractions are assayed in a system containing subthreshold quantities of purified C3bINA. This activity, which has little or no C3b-inactivating activity by itself, but enhances the activity of purified C3bINA, has been termed the C3b inactivator accelerator (A·C3bINA). It is separable from C3bINA on Biorex-70 at pH 7.5, is destroyed by trypsin, but is resistant to di-isopropyl phosphofluoridate.
Identification and Purification of Immunosuppressive Activity in the Urine of Rats and a Human Patient Treated with Niridazole
Authors: Lucas Samuel V. , Daniels Jerry C. , Schubert Richard D. , Simpson Janney M. , Mahmoud Adel A. F. , Warren Kenneth S. , David John R. , Webster Leslie T. 
Published: December 2022

Abstract
Administration of the antischistosomal compound niridazole to mice, guinea pigs, and humans results in the suppression of several manifestations of cell-mediated immunity. Sera from animals treated with niridazole blocked the in vitro production of migration inhibitory factor (MIF) while niridazole itself was inactive, suggesting that these effects are caused by water soluble mediators. We now report that crude extracts prepared from the urine of rats and a patient receiving niridazole, but not from pretreatment control urine, similarly suppress antigen-induced inhibition of migration of peritoneal exudate cells from sensitized guinea pigs. With immunosuppressive activity monitored by the direct MIF assay, combined solvent extraction and chromatographic techniques were used to fractionate immunosuppressive activity from the urine of niridazole-treated rats and the patient; the most active fractions, purified about 100- to 1000-fold as compared to methanol-water extracts of dried voided urine, inhibited MIF production at 0.1 to 0.01 ng/ml of assay mixture. These purified fractions also showed immunosuppressive activity by an in vivo assay wherein doses as low as 1 µg/kg injected intravenously (i.v.) into mice suppressed cell-mediated granuloma formation around Schistosoma mansoni eggs. Identically purified fractions prepared from urine of rats and the patient before they received niridazole showed no immunosuppressive activity either in the MIF or in the granuloma assay systems.
Ir-Gene Control of Antibody Class Production
Authors: Kolb Hubert , Keck Klaus , Momayezi Massoud , Schicker Cornelia , Trissl Dorothea 
Published: December 2022

Abstract
The antibody response in mice to DNP-insulin is under Ir-gene control. The Ir gene defects in two strains have been analyzed. In both cases the IgG immune response was impaired whereas the IgM response was not affected. One H-2 gene haplotype was characterized by lack of IgG response, independent of the immunization protocol. A second H-2 haplotype manifested a low response of IgG after immunization with Bordetella pertussis as an adjuvant but a high response after complete Freund's adjuvant. It is proposed that a low level of T cell help induces the production of IgM antibodies, intermediate levels allow few IgG clones to develop, and high levels induce a heterogeneous IgG response.
Serologic Diagnosis of Lymphogranuloma Venereum by Counterimmunoelectrophoresis with a Chlamydia Trachomatis Protein Antigen
Authors: Caldwell Harlan D. , Kuo Cho-Chou 
Published: December 2022

Abstract
Previously a protein antigen was identified which was common to members of the species Chlamydia trachomatis and to which antibody could be demonstrated in human sera by two-dimensional immunoelectrophoresis. The antigen has been purified by immunoadsorption chromatography, and an exploration undertaken to determine whether the detection of antibody to this antigen by counterimmunoelectrophoresis would be useful for the diagnosis of C. trachomatis infections. Antibody was found in 43 of 45 (96%) sera from patients with lymphogranuloma venerum proven by either isolation or other serologic methods. No positive reactions were observed in 50 patients with nongonococcal urethritis, 38 of whom had evidence of antibody as measured by microimmunofluorescence with whole organism antigen. Sera were also negative from 50 normal individuals, 10 persons with gonorrhea, and 2 patients with psittacosis. Counterimmunoelectrophoresis with purified C. trachomatis protein antigen appears to be a useful serologic test for diagnosis of lymphogranuloma venereum.
Activation of the Alternative Pathway by Pneumococcal Cell Walls
Authors: Winkelstein Jerry A. , Tomasz Alexander 
Published: December 2022

Abstract
The present studies were performed in order to identify the pneumococcal subcellular component responsible for activating the alternative pathway.
Purified pneumococcal cell walls were able to activate the alternative pathway at a concentration as low as 5 µg/ml and were more active than crude cell walls, which in turn were more active than the whole organism. Purified pneumococcal cell membranes also were able to activate the alternative pathway but had less than 10% of the activity of the purified walls. Thus, the cell wall appears to play a major role in pneumococcal activation of the alternative pathway.
Pneumococcal cell walls containing ethanolamine were as effective as cell walls containing choline in activating the alternative pathway. Since C-reactive protein binds specifically to the phosphorylcholine residue of pneumococcal C-polysaccharide, it is unlikely that pneumococcal cell walls must combine with C-reactive protein in order to activate the alternative pathway.
Spleen-Derived Mononuclear Cell Chemotactic Factor in Malaria Infections: A Possible Mechanism for Splenic Macrophage Accumulation
Authors: Wyler David J. , Gallin John I. 
Published: December 2022

Abstract
A hallmark of malaria and several other intravascular infections is the development of splenomegaly associated with splenic macrophage hyperplasia. These macrophages do not arise as a consequence of in situ proliferation of preexisting splenic macrophages, but rather from blood monocytes. To investigate the mechanism of accumulation of blood monocytes in the spleen during the development of splenomegaly, we studied mice and monkeys infected with malaria and mice treated with methyl cellulose. Employing a modified Boyden chamber chemotaxis assay, extracts of washed spleen cells of malaria-infected but not control mice or monkeys were found to contain a factor chemotactic for homologous and human peripheral mononuclear cells. In mice, this factor was present within 4 hours of infection, persisted for the duration of infection, and anteceded a detectable increase in splenic macrophage number by 48 hr. Extracts of lysed parasitized erythrocytes contained no chemotactic activity. Supernatants from in vitro cultures of spleen cells from malaria-infected but not control mice also contained mononuclear cell chemotactic activity. The spleen-derived chemotactic factor was present in nonadherent cells, was water soluble, heat labile, trypsin sensitive and had an estimated m.w. of 80,000 daltons (Sephadex G-150). It contained no serine esterase activity. These observations suggest that infection with malaria and administration of other agents inducing splenomegaly result in the in vivo elaboration of an endogenous spleen-derived mononuclear cell chemotactic factor. This factor, presumably derived from lymphocytes, may be responsible for or contribute to the trapping of blood monocytes in the development of macrophage hyperplasia in the spleen.
The Mononuclear Cell in Human Blood Which Mediates Antibody-Dependent Cellular Cytotoxicity to Virusinfected Target Cells
Authors: Melewicz F. Michael , Shore Steven L. , Ades Edwin W. , Phillips Don J. 
Published: December 2022

Abstract
Studies were carried out to determine whether the mononuclear cell in human blood which mediates antibody-dependent cellular cytotoxicity (ADCC) to herpes simplex virus (HSV)-infected target cells has surface Fc receptors which participate in the reaction.
The F(ab′)2 fragment of human IgG antibody was inactive both in ADCC and in complement-mediated cytolysis, but retained the capacity to neutralize infectious virus, to agglutinate erythrocytes coated with viral antigens, and to bind to the surface of virus-infected cells. Treatment of sensitized virus-infected target cells with staphylococcus protein A, which has affinity for the Fc epitope of IgG, strongly reduced their susceptibility to lysis by ADCC in a dose-dependent relationship. These findings indicate that the Fc portion of IgG antibody to the virus is necessary for cytotoxicity.
Treatment of blood mononuclear cells with either heat-aggregated γ-globulin or HSV immune complexes inhibited effector cell activity. The presence of “third party” cellular immune complexes also strongly inhibited ADCC. Adsorption of mononuclear cells to plastic surfaces coated with soluble third party immune complexes resulted in a significant reduction in effector cell activity.
These findings demonstrate that the ADCC effector cell possesses surface Fc receptors which are utilized in the ADCC reaction. The presence of Fc receptors on the surface of the effector cell indicates that it is a K cell rather than a null cell.
Immunologic Characteristics in Relation to High and Low Leukemogenic Activity of Radiation Leukemia Virus Variants
Authors: Haran-Ghera Nechama , Ben-Yaakov Miriam , Peled Alpha 
Published: December 2022

Abstract
Infection of adult C57BL/6 mice with variants of the radiation leukemia virus resulted in variable leukemia incidence. One variant, designated D-RadLV, induced lymphatic leukemia in 0 to 25% of mice after virus inoculation directly into the thymus of young adult mice. The leukemia incidence could be increased to 80 to 100% by host exposure to x-rays. The second variant, A-RadLV, induced lymphatic leukemia in 80 to 100% of similarly inoculated mice without the need for additional radiation treatment.
Adult mice were inoculated with D-RadLV or A-RadLV. Both variants reduced the immune response to sheep erythrocytes whereas only D-RadLV had an immunosuppressive effect after immunization with a thymus-independent immunogen polyvinyl-pyrrolidone (PVP). Results of transfer experiments indicated that the immunosuppressive effects were expressed at the immunocompetent cell level. Thymusderived cells were affected by A-RadLV since their immunocompetent function was impaired, whereas D-RadLV affected the marrow cell population of immunocytes. Exposure of D-RadLV-inoculated mice to x-rays induced functional impairment of both thymus and marrow cells.
Since the radiation leukemia virus induces “T” lymphatic leukemia it could be proposed that the initial tropism of the virus to thymocytes would lead to high leukemia induction potential, whereas virus tropism to bone marrow cells would yield a low leukemia incidence. The coleukemogenic effect of x-rays could perhaps be related with its capacity to alter and introduce a change in virus-lymphoid cells interaction.
Ontogeny of the Antibody-Forming Cell Line in Mice
Authors: Rosenberg Yvonne J. , Parish Christopher R. 
Published: December 2022

Abstract
The ontogeny of Ig, FcR, and CR-bearing cells in liver and spleen has been followed by using rosetting procedures. These studies demonstrated a sequential appearance of surface receptors during development. Two types of Ig+ cells could be distinguished according to their rosette morphology and adherence to carbonyl iron: 1) an adherent cell which bound few erythrocytes was found predominantly in fetal liver from 13 days gestation and 2) a nonadherent cell which bound larger numbers of erythrocytes appeared in small numbers in fetal liver from day-16 gestation but represented the major Ig+ cell type after birth. Changes in the proportions of receptor-bearing populations occurred at two particular periods during ontogeny. The first was at birth, where an increase in the proportion of FcR+ cells occurred and the proportion of type 2 Ig+ cells rose rapidly. This probably represented the first appearance of FcR+ B lymphocytes even though cells bearing FcR were detected in fetal liver of all ages (days 12 to 18). The second period was around 10 days after birth when the proportion of Ig+ cells again increased concomitant with the appearance of CR+ nonadherent cells.
Identification of Human Peripheral T Cell Antigens
Authors: Koshiba Hirofumi , Ishii Yoshifumi , Yamanaka Noboru , Kikuchi Kokichi 
Published: December 2022

Abstract
A new type of differentiation antigens on human T cells was demonstrated by using a heterologous anti-human T cell serum (ATS). This type of antigen, referred to as human peripheral T cell antigen (HPTA), was found on peripheral T cells and medullary thymocytes, but not on cortical thymocytes and B cells. The percentage of ATS-reactive lymphocytes in human peripheral lymphoid organs was correlated with that of cells rosetting with sheep erythrocytes, but contrasted with the number of B cells defined by the presence of a complement (C) receptor or by rabbit anti-human B cell serum (ABS). ATS also reacted with T cells purified by nylon fiber column filtration but ABS did not. Chronic lymphocytic leukemia cells rosetted with either sheep erythrocytes or erythrocyte-antibody-complement complexes were lysed by ATS and ABS, respectively. Mitogenic responses of blood lymphocytes to phytohemagglutinin (PHA) and concanavalin-A (Con A) were abrogated by treating them with ATS and C, whereas ABS suppressed only their response to Con A. Although numerous thymus cells rosetted with SRBC, only 14% were reactive with ATS. Quantitative absorption studies demonstrated that HPTA content of the thymus cells was much lower than that of lymph node cells.
Anatomical localization of ATS-reactive lymphocytes in human lymphoid organs studied by immunofluorescence indicated that they were present in the thymus-dependent paracortical areas of lymph node and in the medullary region of thymus. ABS, on the other hand, did not stain thymocytes but reacted selectively with the cells located in the lymphoid follicles of lymph node. These data, together with that from cell suspension studies, confirmed that HPTA were shared between medullary thymocytes and peripheral T cells.
Immune Competence of Splenic Lymphocytes Following Graft-vs-Host Disease in Mouse Allogeneic Radiation Chimeras
Authors: Urso Paul , Gengozian Nazareth 
Published: December 2022

Abstract
The abnormal immune response of long-term mouse allogeneic chimeras is reflected by qualitative deficiencies in either T or B lymphocytes. The present study was undertaken to determine if a relationship existed between the severity of graft-vs-host disease (GVHD) that these animals had experienced and a functional defect in either the T or B cell population. The in vitro PFC response of chimera spleen cells to sheep red blood cells (SRBC) was evaluated in the presence of normal T or B lymphocytes 4 to 8 months after marrow transplantation and well beyond the GVHD period. In an analysis of several different allogeneic radiation chimeras, our results showed no relationship between the severity of GVHD experienced and the immunologic capacity of either T or B cells. Thus, different chimera combinations showing similar degrees of GVHD were functionally deficient in one or the other of these two cells types or both with no apparent predilection for abnormality in either population. In examining the quantitative in vitro PFC response to sheep RBC by spleen cells from individual chimeras, we found that the number of PFC formed was related to the severity of GVHD experienced by that animal. A general relationship between severity of GVHD and PFC capacity may also exist between chimeras of different genetic combinations. However, this relationship is not precise since gross exceptions occur. Our results, although documenting further the qualitative abnormalities in T and/or B lymphocytes of radiation chimeras, do not reveal the factor or mechanisms by which these cells are made unresponsive. It is suggested that the tolerance-inducing mechanism of these animals, whether it be humoral blocking factors or suppressor cells, is in some way interfering with the collaboration of T and B cells for antibody production.
Genetic Factors Influencing Mouse Type-C RNA Virus Induction by Naturally Occurring B Cell Mitogens
Authors: Phillips S. Michael , Stephenson John R. , Aaronson Stuart A. 
Published: December 2022

Abstract
The present studies demonstrate that xenotropic type C virus is efficiently released in response to lipopolysaccharide by spleen cells of a wide variety of inbred mouse strains. Lipopolysaccharide-mediated virus release primarily involves B lymphocytes and is in part genetically determined. Virus release can also be efficiently stimulated by other naturally occurring B cell mitogens, including Nocardia water soluble mitogen, and PPD. The evidence indicates that these agents act synergistically with halogenated pyrimidines, but not with each other, to cause virus release. These results indicate that B cell mitogens act to release virus by a mechanism that differs from that of halogenated pyrimidines.
Antigenic Specificity of Opsonophagocytic Antibodies in Rabbit Anti-Sera to Group B Streptococci
Authors: Baltimore Robert S. , Kasper Dennis L. , Baker Carol J. , Goroff Diana K. 
Published: December 2022

Abstract
An opsonophagocytic assay has been developed which requires human polymorphonuclear leukocytes, immune serum, and complement for optimal killing of Group B streptococci. Only with all three of these components was killing of greater than 1.0 log10 of the initial inoculum achieved, using rabbit antisera directed to homologous strains of each of the five known serotypes of Group B streptococci. Titers of specific antisera which opsonized the strains and resulted in τ1 log10 reduction of colony-forming units, ranged from 1:100 (serotype Ib) to 1:3200 (serotype Ia). Cross-reactions between serotype-specific sera and heterologous strains were seen in certain instances. Type Ic strain and serotype Ic antiserum demonstrated cross-reactions with types Ia and Ib which were explainable by known shared antigens among these types. The only other cross-reaction which resulted in τ1 log10 reduction in colony-forming units was when unabsorbed antiserum to strain Ia was used to opsonize a strain of serotype III. Opsonization of 10 serotype III strains was demonstrated with a single type III antiserum. Killing of nine of these strains required polymorphonuclear leukocytes, complement, and antiserum, but one strain, D136C, the reference strain, could be killed (τ1 log10 reduction in colony-forming units) without either complement or specific antiserum.
Inhibition studies were performed utilizing large m.w. polysaccharide antigens extracted from each serotype. These antigens inhibited opsonization of homologous strains by homologous antisera with 50% inhibition points ranging between 0.5 and 4 µg.