bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane Properties and Functional Activity of Lymphocytes from Cyclophosphamide-Pretreated Rats
Authors: Guttmann Ronald D. 
Published: December 2022

Abstract
In an attempt to explain the effect of drug pretreatment on the reduction of allograft immunogenicity, lymphocytes from normal and cyclophosphamide- (CY) pretreated rats were studied in leukocyte culture with phytohemagglutinin or allogeneic cells. Pretreatment with 250 mg/kg CY was associated with complete unresponsiveness as well as the inability to stimulate allogeneic cells. This was dose and time dependent and not explicable by just cell death in culture or drug carryover. CY-pretreated cells gave cytotoxic antibody titration curves suggestive of reduced but not absent surface histocompatibility antigens. Lymphocytes from normal and CY-pretreated rats did not show significant differences in the ability to form caps when reacted with antiimmunoglobulin antisera or in sensitivity to lysis in hypotonic solutions. Thus the cells from CY-pretreated rats appear to have surface alterations associated with the gene product of the MLR locus, decreased serologically detectable transplant antigens, and no serious defect in membrane fluidity or extensibility. This approach provides a potential monitoring system for donor pretreatment in organ allograft situations.
Discontinuous Antibody Secretion during the Secondary Response to Sheep Erythrocytes in Vitro
Authors: Thomas David W. 
Published: December 2022

Abstract
Antibody-producing lymphocytes provide a unique model for studying cellular differentiation and patterns of gene expression in eukaryotic cells as recently reviewed by Lerner and Dixon (1). The relationship between gene expression for antibody synthesis and the cell cycle has been studied in several established antibody-producing cell lines with varying results. Human lymphoid cell lines consistently show the highest level of antibody synthesis in the late G1, early S (2–5), and possibly G2 (5) stages of the cell cycle and a reduced synthesis around metaphase. Similarly, Byars and Kidson (6) demonstrated that established mouse myeloma cells also exhibit maximal antibody synthesis in late G1 and early S, and Gandini-Attardi et al. (7) suggest that mouse myeloma cells contain more antibody in S than in other stages of the cycle. On the other hand, studies by Cowan and Milstein (8) and Liberti and Baglioni (9), also using mouse myeloma cell lines, indicate that antibody is synthesized at a fairly constant rate throughout the cell cycle.
Production of α1 and α2 Immunoglobulin Heavy Chains during Fetal Life
Authors: Cederqvist Lars L. , Litwin Stephen D. 
Published: December 2022

Summary
IgA and its subclasses IgA1 and IgA2 were measured in fetal serum and amniotic fluid throughout gestation by hemagglutination inhibition tests. The IgA1/(IgA1 + IgA2) ratio was higher for fetal serum than for amniotic fluid and was significantly higher in the third than in the second trimester in both amniotic fluid and fetal serum. Am2, a genetic marker for human α2 heavy chains, was typed in a number of combinations of maternal and paternal sera, amniotic fluid, and fetal serum. Three families were informative in that Am2 was present in amniotic fluid, was absent from maternal serum, but present in paternal serum. It was concluded that the fetus synthesized IgA2 in vtero.
Chymopapain C: An Immunosuppressive Protease
Authors: Clagett James A. , Tokuda Sei , Engelhard Warren E. 
Published: December 2022

Abstract
Chymopapain C suppresses the immune responses of mice to both thymus-dependent and independent antigens. We have demonstrated a clear-cut dose and time dependence for the action of this enzyme. When these conditions are optimum, the primary immune response to sheep red cells (SRBC) is completely inhibited when measured by direct plaque-forming cells (PFC), indirect plaque-forming cells, and rosette-forming cells (RFC) during a 10-day experimental period. Immunologic memory was altered in suppressed mice as indicated by quality, quantity, and temporal appearance of the PFC after second injection of antigen. Chymopapain C had a profound suppressive effect on the secondary IgM response when the enzyme was given 1 day before the booster SRBC injection; however, the IgG and RFC responses were not significantly suppressed.
Isolation and Characterization of the Proenzyme form of the C1r Subunit of the First Complement Component
Authors: Valet Gunter , Cooper Neil R. 
Published: December 2022

Abstract
The proenzyme form of C1r was isolated by sequential chromatography of the euglobulin fraction of human serum on DE-32 cellulose, TEAE cellulose, and Sephadex G-200. C1r was found to be a proteolytic enzyme with β-globulin mobility, a sedimentation rate of 7.5S, and a molecular weight of approximately 188,000 daltons. Isolated C1r preparations exhibited an affinity for C1q and C1s, forming a reversible complex with C1q and a firm complex with C1s in free solution.
Isolated C1r preparations did not activate proenzyme C1s, the natural substrate of the C1r enzyme, unless first activated by brief treatment with trypsin, a process accompanied by physicochemical changes in the molecule. It is not known whether the mechanism of conversion of C1r from a proenzyme into an active enzyme during C1 activation is also enzymatically mediated or, alternatively, whether conversion results from conformational changes in C1r induced by the attachment of C1, via C1q, to immunoglobulin molecules.
Detection of Specific Surface Antigens on Cells Transformed by Cytomegalovirus with the Techniques of Mixed Hemagglutination and 125I-Labeled Antiglobulin
Authors: Lausch Robert N. , Murasko Donna M. , Albrecht Thomas , Rapp Fred 
Published: December 2022

Abstract
Cytomegalovirus (CMV)-transformed hamster cells were examined for the presence of virus-specific membrane antigens by using rabbit antiserum prepared against CMV-infected human embryonic lung (HEL) cells. After absorption with sheep erythrocytes and heterologous hamster tumor cells the antiserum reacted specifically with the CMV-transformed cells in the mixed hemagglutination test. The absorbed antiserum did not react with hamster cells transformed by herpes simplex virus type 2 or PARA-adenovirus 7 or with untransformed hamster embryo fibroblasts. These results were confirmed with the 125I-labeled antiglobulin technique. Absorption with HEL cells rendered the antiserum specific for HEL cells infected with CMV. This reactivity was lost after absorption with 107 CMV-transformed cells but not with 107 hamster embryo fibroblasts. These results establish that CMV-transformed hamster cells express virus-related membrane antigen(s), and that the same antigen(s) is also found on CMV-infected human cells.
Secondary Cytotoxic Tumor Immune Response Induced in Vitro
Authors: Röllinghoff M. 
Published: December 2022

Abstract
For the investigation of a secondary cell-mediated anti-tumor immune response a syngeneic mouse plasma cell tumor system was used. The primary immunization was performed in vivo, whereas the secondary response was induced in vitro. Evidence is presented that a secondary anti-tumor cell response was characterized by an accelerated and enhanced reaction when compared to a primary anti-tumor response. Furthermore, our findings suggested that the secondary response studied was antigen-specific. The induction of a secondary response did not appear to depend on the persistence of differentiated cytotoxic effector lymphocytes, as measured in a 51Cr release assay. The effector phase of the secondary anti-tumor response, however, seemed to require T lymphocytes. These data appear to be compatible with the view that a secondary anti-tumor cell response is dependent on the presence of a set of antigen-reactive cells, which operationally can be designated in analogy to the secondary B cell response as memory cells.
Polymerized Ragweed Antigen E
Authors: Patterson Roy , Suszko Irena M. 
Published: December 2022

Abstract
The antigenic characteristics of three preparations of ragweed (RW) antigen E were studied in rabbits. The preparations consisted of the monomeric form, (m.w. 37,800); a lower molecular weight polymer (m.w. 0.2 to 4 million) and a higher molecular weight polymer (m.w. 4 to 20 million). Antibody responses of two Ig classes occurred. A circulating antibody response detectable by an ammonium sulfate-binding technique was consistent with an IgG response. A homocytotropic antibody response, probably rabbit IgE, occurred in a majority of animals. The polymerized RW preparations appeared as antigenic as the monomer in induction of the IgG response. The low molecular weight polymer resulted in a lower and later reaginic antibody response than either the monomer or high molecular weight polymeric preparation.
The Role of Humoral Factors in the Initiation of in Vitro Primary Immune Responses
Authors: Watson James , Thoman Marilyn , Ralph Peter , Trenkner Ekkhart 
Published: December 2022

Abstract
The nature of the adherent cell type that is required for the induction of immune responses to erythrocyte antigens in mouse spleen culture has been investigated. Bone marrow-derived mononuclear cells were grown in liquid culture systems in the presence of a colony stimulating factor. These mononuclear cells exhibit adherent, phagocytic, staining, rosette-forming, and cytotoxic properties characteristic of macrophages. However, such macrophage-like cells do not replace spleen adherent cells in the induction of immune responses to erythrocyte antigens in mouse spleen culture. Treatment of macrophage-like cells with normal mouse serum, hyperimmune anti-sheep erythrocyte (SRBC) serum or thymus-derived cells activated to SRBC did not render these cells capable of restoring immune responses in adherent cell-depleted cultures. These findings suggest that the macrophage may not be the adherent cell type required for cooperative events in the induction of antibody synthesis. Adherent cell types may play two roles in the induction of immune responses to SRBC. A phagocytic role for the digestion of particulate antigens such as SRBC may be performed by a macrophage-like cell. Another cell type may be required in delivering part of the inductive stimulus to precursor antibody-forming cells or to thymus-derived helper cells.
Aggregation of Fc′µ Subfragments Produced by Tryptic Hydrolysis of Human IgM at Elevated Temperature
Authors: Chen James P. , Beyer Carol B. , Elakovich Stella D. 
Published: December 2022

Abstract
The proteolysis of Waldenstrom macroglobulins into Fabµ and (Fc)5µ fragments by tryptic digestion at 56°C to 65°C was reexamined. It appeared that “(Fc)5µ fragment” is composed of both Fc′µ subfragments and residual “(Fc)5µ fragment” held together by non-covalent forces.
Sephadex G-200 chromatography resolved a 65°C tryptic digest of IgM into three peaks: GI, (Fc)5µ fragment; GII, Fabµ fragment; and peptides. Gel-filtration of an identical IgM digest through Sepharose 6B resulted in four peaks: BI, BII, BIII and peptides. BIII with m.w. 52,000 according to SDS polyacrylamide gel electrophoresis is Fabµ fragment. GI and BII, having sedimentation coefficients of 9.9S and 0.1S, respectively, were found to be antigenically equivalent according to Fcµ specific antisera. BI is apparently a high molecular weight aggregate of Fc′µ subfragments of 10,000 m.w. This aggregate was antigenically deficient in Fcµ determinants to both GI and BII. SDS gel electrophoresis showed that the appearance of BI subfragment was not dependent upon reduction and alkylation. This suggests that BI is derived from a region of the µ-chain other than the area containing inter-µ-chain disulfide bonds. Reduced-alkylated GI is characterized by major protein bands at m.w. 10,000, 12,500, 16,000, and 43,000 in SDS gel electrophoresis. BII, whose reduced-alkylated form is devoid of the band corresponding to m.w. 10,000, is most likely residual “(Fc)5µ fragment”.
It appears that BI results from further fragmentation of (Fc)5µ fragment with subsequent aggregation. The release of BI is temperature dependent starting at 59°C and is greatest at 65°C. BI contains &lt; 2% hexose and is presumably derived from a carbohydrate poor Cµ domain; BII contains 11% hexose. BI fraction was further purified by passage through a Sepharose 6B column equilibrated with 5 M guanidine HCl. Comparison of preliminary N- and C-terminal sequence data with published IgM sequence data shows BI subfragment to be located in the C-terminal region of Fcµ fragment.
IgD: A Major Immunoglobulin on the Surface of Lymphocytes from Patients with Chronic Lymphatic Leukemia
Authors: Kubo Ralph T. , Grey Howard M. , Pirofsky Bernard 
Published: December 2022

Abstract
Previous studies on the characterization of surface immunoglobulins of lymphocytes from CLL2 patients indicated that the cell-associated immunoglobulin was monoclonal with respect to heavy and light chain class with IgM being by far the most common Ig class observed (1–4). Our earlier study of CLL involved analysis for the presence of IgG, IgA, and IgM. Some cases were observed in which neither heavy nor light chains were detectable and others in which only light chains could be detected (1). A more detailed investigation of one of these patients demonstrated IgD as the major Ig class associated with these cells. We have accordingly evaluated other unselected cases of CLL for the presence of IgD on the lymphocyte surface. The current report details these studies and the relationship of IgD to IgM on the surface of CLL lymphocytes.
Methods. Lymphocytes were obtained from patients with CLL having white blood counts ranging from 20,000 to 200,000 cells/mm3.
Reactions between Certain Strains of Pneumococci and Fc of IgG
Authors: Stephens Christopher G. , Reed William P. , Kronvall Göran , Williams Ralph C. 
Published: December 2022

Abstract
A non-immune reaction is known to occur between the Fc region of certain IgG subclasses and cell wall components of staphylococci (protein A) and streptococci. Pneumococci have been studied for similar activity.
Seventy-six strains of Diplococcus pneumoniae were evaluated for non-immune reactivity with γ-globulin Fc by testing their ability to agglutinate erythrocytes which were coated with sub-agglutinating quantities of anti-erythrocyte antibody. Thirty (39%) of the strains were reactive. All strains of some pneumococcal serotypes were reactive, whereas all strains of other serotypes were negative. The reactivity appeared to be a property of the polysaccharides since particles coated with purified polysaccharides from reactive serotypes also caused agglutination. When the capsule size of pneumococci was varied by using encapsulated and non-encapsulated mutants, augmentation by mouse passage, or varying cultural conditions, reactivity was greater if the capsule was larger. Inhibition experiments showed the reactivity to be in the Fc fragment, and IgG1 was the only highly reactive immunoglobulin. IgG2 and IgA were probably non-reactive; and IgG3, IgG4, and IgM were clearly non-reactive.
The Ability of Chemotactic Factors to Induce Lysosomal Enzyme Release
Authors: Becker Elmer L. , Showell H. J. 
Published: December 2022

Abstract
Lysosomal enzyme release form rabbit peritoneal neutrophils induced by a bacterial chemotactic factor is temperature dependent; it requires external Ca2+ but not Mg2+ glycolysis as a source of metabolic energy and free sulfhydryl groups. The release is inhibitable by DFP under circumstances suggesting involvement of an activatable serine esterase. The release is enhanced by cytochalasin B. Low concentrations of colchicine and vinblastine enhance lysosomal enzyme release, as well as chemotaxis induced by the same chemotactic factor; higher concentrations inhibit.
Enzymatic Digestion of the First Component of Human Complement (Clq)
Authors: Knobel Hans R. , Heusser Christoph , Rodrick Mary L. , Isliker Henri 
Published: December 2022

Abstract
Human C1q was shown to be sensitive to digestion by trypsin, chymotrypsin and collagenase, but not by elastase. Treatment with trypsin and chymotrypsin caused a rapid loss of the hemolytic activity of C1q and its ability to fix to immune complexes. Collagenase digestion of C1q resulted in a rapid loss of the hemolytic activity also, whereas the ability to bind to immune complexes decreased slowly and remained at a constant value of 15%. In contrast to trypsin and chymotrypsin, collagenase treatment of 125I-labeled C1q led to well defined fragments, only some of which were labeled. Adsorption of collagenase-digested C1q on ovalbumin-antiovalbumin complexes indicated the larger non-covalently bound peripheral subunits of C1q to be involved in fixation to immune complexes. None of the fragments was able to initiate lysis in the presence of RC1q. Immunologic analysis of the digest revealed at least two different fragments with respect to antigenicity.
Cell-Mediated Immunity in Vitro: A Highly Sensitive Assay for Human Lymphotoxin
Authors: Spofford Bryan T. , Daynes Raymond A. , Granger Gale A. 
Published: December 2022

Abstract
A new in vitro technique for the assay of human lymphotoxin (LT) is described. The method uses monolayer tube cultures of an exquisitely sensitive cell type pretreated with mitomycin-C (MC). The use of MC permits the differentiation of growth inhibition and actual cytotoxicity. In addition, the use of MC-treated target cells considerably increases the sensitivity of the LT assay. The method is very simple, rapid, reproducible, and more sensitive than present assays for LT or any other lymphokine. The utility of this assay lends itself to routine application in research and in clinical situations.
Cellular Bases for Relative Radioresistance of the Antibody-Forming System at Advanced Stages of the Secondary Response to Tetanus Toxoid in Mice
Authors: Grobler Peter , Buerki Heinz , Cottier Hans , Hess Max W. , Stoner Richard D. 
Published: December 2022

Abstract
Nearly normal secondary tetanus antitoxin responses were produced by young adult female mice subjected to 600 rads of 60Co gamma whole-body radiation 4 days after secondary antigenic stimulation via the hind leg footpads. In an attempt to correlate the rapid transition from radiosensitivity of the antibody-forming system on day 3 to relative radioresistance on day 4 after booster, we carried out studies on cytokinetics in regional (popliteal) lymph nodes and on incorporation of 3H-l-histidine into circulating antitoxin. Analyses of tritium radioactivity in antigen-antibody precipitates of pooled sera 2 hr after i.v. injection of the labeled amino acid revealed maximum incorporation into antibody around day 7 after booster in nonirradiated controls, and around day 12, i.e., 8 days after radiation, in experimental mice, respectively. Relative radioresistance of the antibody-forming system on day 4 after booster, as opposed to day 3, was attributed to the finding that plasmacellular proliferation in medullary cords reached a marked and narrow peak on day 3 and had almost subsided to control levels between days 4 and 5. Accordingly, many medullary plasma cells survived and continued to proliferate after exposure to radiation. In contrast, germinal centers, which largely determine the overall maximum DNA synthetic activity in the lymph node and attain their full development in non-irradiated animals only 5 to 6 days after booster, were completely destroyed by radiation within 1 day. Since a) antibody production persisted despite the disappearance of germinal centers; and b) mice irradiated 4 days after booster have previously been shown to lack tertiary responsiveness, the present findings lend strong support to the hypothesis that germinal center cells were involved more in the generation of memory cells than in active antibody secretion. The results do not favor the assumption of a marked contribution of germinoblasts to the antibody-forming plasma cell population elicited by the same stimulus which had triggered germinal center formation.
Induction of Marked Hypergammaglobulinemia with Xenogeneic Tumors in Hamsters: Immunopathologic Studies
Authors: Richman Alan Ve , Defendi Vittorio 
Published: December 2022

Abstract
Human heteroploid cells derived from a benign prostatic adenoma, MA160, can grow progressively in the subcutaneous tissues of 2-day-old nonimmunosuppressed hamsters. The growth of these xenografts is associated with certain immunopathologic features. These features are: A marked increase in the serum of electrophoretically restricted IgG which parallels tumor growth.The appearance of noncytotoxic antibody against membrane antigens of the transplanted cells which is related to the IgG elevation but which constitutes only a very minor part of this elevation; and the fixation of antibody to the tumor cell membrane in situ.The extensive plasma cell proliferation, and the presence of circulating immune complexes (as indicated by the granular deposition of IgG and complement (C3) in the renal glomeruli).The lack of demonstrable biologic activity of the serum (enhancement or cytotoxicity).
This transplantation system has analogies with certain chronic viral infections in animals; and our inability to detect antibody specificity for much of the IgG may be related to the presence of circulating immune complexes. Finally we suggest that this system may provide a model from which to study the evolution and pathogenesis of plasma cell dyscrasias.