bluuebunny/crossref_metadata_2025 huggingface dataset:
C3 convertase of human complement: enhanced formation and stability of the enzyme generated with nickel instead of magnesium.
Authors: Fishelson Z , Müller-Eberhard H J
Published: December 2022

We demonstrate that nickel++ (Ni) can replace Mg in the formation of the C3b,Bb enzyme, and that Ni is more efficient in enzyme formation than Mg. C3b-bearing sheep erythrocytes (EC3b) were used to measure radiolabeled Factor B uptake and C3 convertase activity. Up to nine times more Factor B was specifically bound to EC3b in the presence of Ni than in the presence of Mg under identical conditions. To form one effective hemolytic site (1 Z) per EC3b cell with Ni, three times less Factor B, 12 times less Factor D, and 66 times less metal ion were required than when using Mg. The C3b,Bb formed with Ni (C3b,Bb(Ni)) had a 5 to 10 times longer half-life at different temperatures than the enzyme formed with Mg (C3b,Bb(Mg)). Native properdin stabilized C3b,Bb(Ni) to the same extent as C3b,Bb(Mg) (four to five times) and Factor H accelerated similarly the decay of both enzymes. Ni could also replace Mg in the formation of the C4b,2a enzyme. C4b,2a formation was measured by using C1 and C4b-bearing sheep erythrocytes (EAC1,4b) and native C2. To form 1 Z per EAC1,4b cell with Ni, two times less C2 and 60 times less metal ion were required than when using Mg. The half-life of the C4b,2a formed with Ni was two times longer than that formed with Mg. Decay of both C3b,Bb and C4b,2a enzymes formed either with Mg or with Ni was unaffected by EDTA. These results show that Ni is more efficient than Mg in the generation of both enzymes and suggest that Ni binds to the Mg-binding sites of the enzymes with a higher affinity than Mg.
Augmentation of phagocytosis by a specific fibronectin fragment that links particulate activators to the fibronectin adherence receptor of human monocytes.
Authors: Czop J K , Austen K F
Published: December 2022

Intact human plasma fibronectin of 44,000 m.w. and a fibronectin fragment of 180,000 m.w. promote dose-dependent adherence of gelatin-coated particles to human monocytes without phagocytosis. Both of these proteins, however, augment monocyte ingestion of gelatin-coated targets that are particulate activators of the alternative complement pathway or of nonactivators bearing IgG. Unlike intact fibronectin, the 180,000 m.w. fragment also binds directly to particulate activators that lack gelatin to augment their phagocytosis by human monocytes. Prior attachment to monocytes of gelatin-coated sheep erythrocytes bearing increasing concentrations of intact fibronectin decreases in a dose-dependent fashion the capacity of these monocytes to engage in augmented phagocytosis of particulate activators opsonized with the 180,000 m.w. fibronectin. Occupation of the monocyte fibronectin receptors with particle-bound, intact fibronectin does not decrease monocyte phagocytosis of plain particulate activators or of IgG-coated particles. Thus, the 180,000 m.w. fibronectin fragment both directly opsonizes particulate activators and interacts with monocyte fibronectin receptors to promote particle adherence, thereby enhancing phagocytosis through a concerted action with the distinct receptors for particulate activators.
Anti-Sm autoantibodies in MRL mice: in vitro detection and generation of antibody-forming cells.
Authors: Cohen P L , Eisenberg R A
Published: December 2022

Antibodies to the nuclear antigen SM are specific for systemic lupus erythematosus in humans and mice. In order to study the cellular mechanisms of anti-Sm generation, a hemolytic plaque assay to identify and enumerate lymphocytes secreting anti-Sm has been developed by using SRBC coated with purified Sm by a modified carbodiimide technique. Anti-Sm-specific PFC were found in MRL/Mp-Ipr/Ipr and MLR/Mp- +/+ mice whose sera contained anti-Sm, but were never detected in anti-Sm-negative MRL mice or in normals. Spleen cells from anti-Sm-positive MRL/Mp-Ipr/Ipr mice generated anti-Sm PFC spontaneously after 4 days of in vitro culture, whereas cells from normal mice or anti-Sm-negative MRL mice were never observed to produce spontaneous anti-Sm, even when cultured in the presence of bacterial lipopolysaccharide. The generation of anti-Sm by MRL cells in vitro was found to be dependent on the presence of T cells, but the ability of cells from individual MRL mice to generate anti-Sm appeared to be limited by the availability of Sm-specific B cell precursors and not due to a relative absence of T cells capable of providing help for the anti-Sm response. Analysis at the cellular level of the in vitro generation of a disease-specific autoantibody by using the methods described should facilitate understanding of mechanisms of autoreactivity.
Surface phenotype of Peyer's patch germinal center cells: implications for the role of germinal centers in B cell differentiation.
Authors: Butcher E C , Rouse R V , Coffman R L , Nottenburg C N , Hardy R R , Weissman I L
Published: December 2022

The surface phenotype of Peyer's patch germinal center lymphoid cells in the mouse is described. It is confirmed that most germinal center lymphocytes bind high levels of peanut agglutination (PNA), a lectin with specificity for terminal galactosyl residues. It is shown that germinal center lymphocytes can be identified in cell suspensions as a discrete PNAhi population distinct from other B cells, plasma cells, and most T cells, which bind only low levels of PNA. Using fluorescence-labeled PNA as a marker in dual fluorescence studies, we found that the majority of Peyer's patch germinal center cells are B lymphocytes: PNAhi Peyer's patch cells express B220, the B lineage-specific form of the T200 family of molecules, as well as low levels of surface Ig. They do not express the T cell-lineage antigens Thy-1, Lyt-1, or Lyt-2 (only 1 to 3% positive). They bear lower levels of H2-K than PNAlo B cells, but two to three times the level of surface I-A-encoded determinants. A discrete but variable subpopulation of PNAhi Peyer's patch cells bear ThB in AKR/c mice, but BALB/c PNAhi lymphocytes are ThB-. About 10 to 30% bear surface IgM or IgG, but in contrast to essentially all PNAlo B lymphocytes in this site, they express no detectable surface IgD. The majority of Peyer's patch germinal center cells bear surface IgA, and this IgA is allelically excluded in F1 mice, indicating it is synthesized by the germinal center cells themselves. In fact, germinal centers contain most of the IgA-bearing cells in Peyer's patches (70 to 85%). These findings lend considerable support to the concept that germinal centers in Peyer's patches are the site of generation of precursors of the IgA-secreting plasma cells that characterize mucosal immune responses, and also suggest that germinal centers may play an important role in the process of heavy chain class switching.
Bromination of guanosine and cyclic GMP confers resistance to metabolic processing by B cells.
Authors: Goodman M G , Weigle W O
Published: December 2022

The metabolic fates of 8-bromoguanosine (8BrGuo) and 8-bromoguanosine-3'5'-cyclic monophosphate (8Br-cGMP) were examined in cultures of murine B lymphocytes. These compounds exert striking immunostimulatory effects upon bone marrow-derived lymphoid cells in vitro. Both 8BrGuo and 8Br-cGMP were resistant to metabolic processing by these cells. That purine metabolic pathways are intact and operant in B cells was demonstrated by the ready degradation and phosphorylation of native guanosine and cyclic GMP. Inaccessibilty of the substrate to the relevant enzymes was ruled out as an explanation by the observation that the brominated compounds also were resistant to processing in broken cell preparations. Moreover, 8BrGuo did not interfere with the cellular machinery for metabolizing native guanosine. The implications of these observations for studying the actions of purine nucleotides, cyclic nucleotides, and their enzymatic processing in B cells are discussed.
Monoclonal antibodies reacting with immunogenic mycoplasma proteins present in human hematopoietic cell lines.
Authors: Hemler M E , Strominger J L
Published: December 2022

During studies of human hematopoietic cells, two novel anti-mycoplasma monoclonal antibodies reacting in human cell surface binding assays were generated. These monoclonal antibodies define antigens (called MP71 and MP33) that showed variable positive and negative expression in different cultures of the same human cell lines. Furthermore, negative cell cultures could be converted to positive cultures upon incubation with filtered media from a previously positive cell culture. A DNA staining assay was used to demonstrate the presence of mycoplasma in the cultures positive for MP71. The expression of MP71 on a panel of cell lines always correlated with the expression of MP33, suggesting that the latter antigen is also mycoplasma related. The monoclonal antibodies against both antigens (MP71 and MP33) were each able to block the growth of mycoplasma newly transferred to hematopoietic cell cultures. Biosynthesis of these mycoplasma antigens differed from biosynthesis of host cell surface antigens in that the former showed a relative insensitivity to gamma irradiation. Internal labeling with 35S-methionine or host cell surface labeling with 125I and analysis by immunoprecipitation showed that the antigens MP71 and MP33 had sizes of Mr 71,000 and 33,000, respectively. Also the antigen MP71 was almost completely, although transiently, cleared from the host cell surface by trypsin. Growth inhibition analysis of different mycoplasma species indicated that the monoclonal antibody recognizing MP71 was uniquely reactive with Mycoplasma hyorhinis.
In vitro and in vivo effector function of rat IgG2a monoclonal anti-S. mansoni antibodies.
Authors: Grzych J M , Capron M , Bazin H , Capron A
Published: December 2022

Rat IgG2a monoclonal antibodies have been produced after fusion of spleen cells from LOU/C rats infected with S. mansoni for 5 wk and IR983F nonsecreting rat myeloma cells. The cell supernatants of one particular IgG2a-producing clone (IPL Sm1) as well as ascitic fluids induced by this clone revealed anti-S. mansoni activity detected by immunofluorescence on schistosoma sections. In vitro studies of the effector function of such antibodies revealed that the rat IgG2a monoclonal antibodies mediated high levels of rat eosinophil-dependent cytotoxic effect against S. mansoni schistosomula, similar to that obtained with 5-week infected rat serum. Passive transfer experiments carried out with IPL Sm1 ascitic fluid showed a significant level of passive protection against a challenge infection. These results indicate a possible use of the monoclonal antibodies in analyzing in vivo functions of IgG2a antibodies, as well as in isolating potentially protective target antigens.
Specificity of T lymphocyte cytotoxicity to autologous hepatocytes in chronic hepatitis B virus infection: evidence that T cells are directed against HBV core antigen expressed on hepatocytes.
Authors: Mondelli M , Vergani G M , Alberti A , Vergani D , Portmann B , Eddleston A L , Williams R
Published: December 2022

Peripheral blood T lymphocytes from 21 patients with chronic HBV infection were incubated with autologous hepatocytes in a microcytotoxicity assay. Cytotoxicity was significantly increased in 13 cases, and in 12 of these the cytotoxic effect of the T lymphocytes was inhibited by preincubating the liver cells with IgG containing antibodies to the hepatitis B core antigen (HBcAg). Normal human IgG and IgG containing antibodies to the hepatitis B surface antigen (HBsAG) were without effect. Control experiments using autologous fibroblasts as target cells showed low levels of T cell cytotoxicity and no blocking effect of anti-core antibody. All patients in whom it was possible to demonstrate HBcAg in liver tissue had significantly increased T cell cytotoxicity to autologous hepatocytes. These studies suggest that T cell cytotoxicity in patients with chronic HBV infection is directed against determinants resembling the hepatitis B core antigen on the plasma membrane of hepatocytes.
Macrophage activation for tumor cytotoxicity: induction of macrophage tumoricidal activity by lymphokines from EL-4, a continuous T cell line.
Authors: Meltzer M S , Benjamin W R , Farrar J J
Published: December 2022

Supernatant culture fluids from a phorbol myristate acetate (PMA) stimulated variant of the murine EL-4 thymoma cell line activated inflammatory macrophages for nonspecific tumoricidal activity in vitro; active supernatants fluids were not directly toxic to tumor target cells in the absence of macrophages. Macrophages treated with culture fluids of unstimulated and concanavalin A-stimulated EL-4 or PMA-stimulated cells derived from any of ten other continuous T cell lines were not cytotoxic. The titer of activity in lymphokines from PMA-stimulated EL-4 was similar to that from antigen-stimulated spleen cell cultures. Spleen cell and EL-4 derived activities were both retained within a dialysis membrane and destroyed by heating at 100 degrees C for 15 min. However, unlike the activity in spleen cell-derived LK, activity in EL-4 culture fluids was stable to dialysis against pH 2 buffer. Further physicochemical characterization of the EL-4 activity showed two different factors that activated macrophages for cytotoxicity: one was indistinguishable from gamma interferon (IFN) (antiviral activity, 50,000 m.w., pI 4.2 to 6.0, pH 2 labile and neutralized by anti-gamma IFN serum); the other was clearly distinct (no antiviral activity, 23,000 m.w., pH 2 stable and unaffected by anti-gamma IFN serum). These results suggest that the EL-4 cell line may produce one or more of the macrophage activation factors present in spleen cell-derived lymphokines.
Major histocompatibility antigens and mononuclear inflammatory infiltrate in benign nevomelanocytic proliferations and malignant melanoma.
Authors: Ruiter D J , Bhan A K , Harrist T J , Sober A J , Mihm M C
Published: December 2022

The presence of major histocompatibility antigens in malignant melanoma and benign nevomelanocytic lesions and the nature of associated mononuclear inflammatory cells were studied in situ by using monoclonal antibodies and an immunoperoxidase technique. HLA-A,B,C (HLA) and beta 2-microglobulin (beta 2m) were found on malignant melanocytes in primary cutaneous and metastatic melanomas. In contrast, HLA antigens were not identified on nevomelanocytes in benign hyperplasia or nevocellular nevi, although in some cases faint staining for beta 2m was present. The staining of nevomelanocytes for HLA and beta 2 was variable in cases of nevomelanocytic dysplasia. The degree of mononuclear cellular response correlated with the expression of HLA (or beta 2m) on nevomelanocytes. Most of the inflammatory cells were identified as T cells. The majority of T cells were of helper/inducer phenotype, whereas a lesser number were phenotypically suppressor/cytotoxic T cells. The findings suggest that expression of HLA may be involved in triggering or eliciting a cellular immune response against dysplastic or malignant nevomelanocytes.
Mechanisms of human cell-mediated cytotoxicity. III. Dependence of natural killing on microtubule and microfilament integrity.
Authors: Katz P , Zaytoun A M , Lee J H
Published: December 2022

To date, the mechanisms of human natural killer (NK) cell activity have been poorly defined. Since microtubules and microfilaments are important in many non-NK leukocytic processes, the potential roles of these cellular elements in natural killing were assessed in simultaneously performed 51-chromium-release microcytotoxicity and single cell cytotoxicity assays. The microtubule inhibitors colchicine, vincristine, and vinblastine suppressed chromium-release in a concentration-dependent fashion. This suppression could be prevented by the promoters of microtubule assembly, deuterium oxide and cyclic GMP. Microtubule inhibitors did not affect the binding of natural killer cells to target cells but did suppress the lysis of bound targets. The "recycling" of natural killer cells to repeat the lytic sequence was not altered by microtubule-disrupting agents. Cytochalasin B, a microfilament inhibitor, induced dose-dependent suppression of lytic activity in the chromium-release assay. Concentrations of cytochalasin B greater than 2 micrograms/ml prevented the binding of effector cells to target cells. Concentrations of cytochalasin B less than 2 micrograms/ml depressed killing in the chromium-release assay but did not alter target cell binding or the lysis of bound targets indicative of an inhibition of effector cell recycling. Concentrations of cytochalasin B greater than 2 micrograms/ml did not affect the lysis of bound targets once binding had occurred. The roles of microtubules and microfilaments in the lytic sequence can therefore be subdivided based on these data: 1) the binding of natural killer cells to target cells in dependent on microfilaments; 2) the lysis of bound targets requires microtubule assembly; and 3) the subsequent post-lytic recycling of natural killer cells necessitates a intact microfilament system.
A New Plan for Applying the Specific Treatment of Pollen Hay Fever (Perennial Treatment)
Authors: Brown Aaron
Published: December 2022

A modification of the specific treatment of hay fever is presented consisting in a distribution of the injections at three- to four-week intervals, throughout the year, instead of the usual pre-seasonal injections at five- to seven-day intervals. The few constitutional reactions observed in the treatment are not sufficient to contraindicate its use.
Blood Grouping of the Polar Eskimo
Authors: Heinbecker Peter , Pauli Ruth H.
Published: December 2022

Summary and Conclusions

The blood grouping of the Polar Eskimo has been determined. Of the individuals studied 80.65 per cent fall into group I. Those falling into groups II, III, IV, were generally shown to be half-breeds. The blood of the pure Polar Eskimo falls into group I (Landsteiner-Jansky).
The Absorption of the Toxic Substance of Normal Goat Serum by Guinea Pig Tissue
Authors: Aronson Joseph D.
Published: December 2022

It has long been recognized that certain tissue cells can fix toxic substances. Wassermann and Takaki (1) claimed that the brain and cord of normal guinea pigs could fix tetanus toxin. Similar claims have been made by Kempner and Schepilewsky (2) for botulinus toxin, and by Guillain, Laroche and Grigaut (3) for diphtheria toxin. Sachs (4) has shown that arachnolysin prepared from spiders is hemolytic for rabbit cells but that it is not hemolytic for guinea pig cells, and furthermore, corresponding with this specificity, the hemolysin of arachnolysin is absorbed by the stroma of rabbit erythrocytes, but not by the stroma of guinea pig erythrocytes. Similar observations were made by Jacoby (5) with crotin, prepared from the seeds of Croton tiglium, which is hemolytic for rabbit cells, but not for those of the guinea pig or dog. That calf erythrocytes have a selective action for the neurotoxic and hemolytic property of cobra venom has been claimed by Bang and Overton (6).
Characterization of warm-reactive IgG anti-lymphocyte antibodies in systemic lupus erythematosus. Relative specificity for mitogen-activated T cells and their soluble products.
Authors: Litvin D A , Cohen P L , Winfield J B
Published: December 2022

In addition to previously described cold-reactive IgM anti-lymphocyte antibodies maximally cytotoxic for resting cells at 15 degrees C, sera from patients with systemic lupus erythematosus (SLE) were found to contain a new type of antibody preferentially reactive at physiologic temperatures with mitogen-activated lymphocytes. This antibody lacked specificity for unstimulated lymphocytes, and was shown to be of the IgG class both by indirect immunofluorescence and in immunochemical experiments. Certain SLE sera also contained IgG antibodies with the capacity to develop plaques with mitogen-activated T lymphocyte preparations used in a reverse hemolytic plaque assay, indicating reactivity with products released by activated cells. The elimination of the ability of SLE sera to develop plaques after absorption with viable mitogen-stimulated lymphocytes, but not with resting cells, suggested that these antibodies were directed toward activation "neoantigen(s)" shed from the cell surface membrane. Surface membrane phenotype analyses performed by using a variety of monoclonal antibody reagents indicated that the plaque-forming cells (PFC) detected with SLE sera were activated T lymphocytes not restricted to single OKT4+, OKT8+, or Ia antigen+ subpopulations. Essentially all PFC expressed transferrin receptors. The present data raise the possibility that certain of the interesting effects of anti-lymphocyte antibodies on immunologic function in SLE may be mediated by interactions of these new type(s) of antibodies with activated lymphocytes or their products, rather than through blocking or depletion effects on resting precursor cells.
Induction of experimental allergic encephalomyelitis in PL/J and (SJL/J x PL/J)F1 mice by myelin basic protein and its peptides: localization of a second encephalitogenic determinant.
Authors: Fritz R B , Chou C H , McFarlin D E
Published: December 2022

SJL/J, PL/J, and (SJL/J x PL/J)F1 mice were immunized with bovine, guinea pig, mouse, or rat myelin basic proteins (MBP) in adjuvant containing Mycobacterium tuberculosis H37Ra. Twenty-four and 72 hr later, Bordetella pertussis vaccine was given i.v. All MBP tested induced experimental allergic encephalomyelitis (EAE) in SJL/J and F1 mice; however, bovine MBP was inactive in PL/J mice. Each strain was immunized in a similar manner with peptic peptides, residues 1-37, 43-88, and 89-169 of guinea pig MBP. In contrast to the SJL/J strain, which has been shown to recognize a major encephalitogenic determinant in peptide 89-169, PL/J and F1 mice responded primarily to an encephalitogenic determinant within peptide 1-37. Analysis of antibody levels showed that SJL/J mice made no antibody to peptide 1-37, although anti-peptide 89-169 antibodies were consistently found. Conversely, PL/J mice responded well to peptide 1-37, but only an occasional animal made a significant response to peptide 89-169. (SJL/J x PL/J)F1 mice were more susceptible to EAE than either parental strain, as shown by the percentage of animals showing neurologic signs and by clinical severity.
The effect of temperature on the activation of thymocytes by interleukins I and II.
Authors: Hanson D F , Murphy P A , Silicano R , Shin H S
Published: December 2022

Endogenous pyrogen (EP) and interleukin (IL 1) appear to be closely related or identical. We therefore conducted experiments to test whether the central action of EP (fever) enhanced its local action (potentiation of immune responses). We found that 3H-TdR incorporation by thymocytes stimulated with IL 1 in the presence of 5 micrograms/ml of phytohemagglutinin (PHA) was strongly enhanced by small rises of temperature in the 32 to 38 degrees C range. Responses at 40 degrees C were generally less than those seen at 38 degrees C. Calculated values for the temperature coefficient (Q10) of the PHA-facilitated response to IL 1 varied between 50 and 300 in different experiments. Thymocytes had a variable response to IL 1 in the absence of PHA. However, thymocytes that failed to agglutinate with peanut agglutinin responded consistently to IL 1 alone, and these mitogenic responses were strongly temperature sensitive (Q10, 50 to 100 in different experiments). Thymocyte responses to 5 micrograms/ml PHA were only modestly sensitive to temperature (Q10, 3 to 8), and responses to interleukin 2 gave Q10 values of 3 to 24, with a mean of about 9. The responses of CTL cells to IL 2 were also modestly enhanced by small increases of temperature, and calculated Q10 values were similar to those observed for thymocytes. IL 1 production by macrophages was also not greatly enhanced by temperature (Q10, 2 to 5). These observations suggest that small increases of temperature enhance IL 1 activity to a much greater degree than they enhance the activity of other components of the immune response. This may help to explain the conservation of two such apparently disparate activities as EP and IL 1 in the same molecules.
Modulation of IL 2-dependent growth of mouse NK cells by interferon and T lymphocytes.
Authors: Riccardi C , Vose B M , Herberman R B
Published: December 2022

The regulatory role of interferon (IFN) on the growth of mouse natural killer (NK) cells in the presence of interleukin 2 (IL 2) was analyzed by the limiting dilution assay. Pretreatment for 5 hr with IFN (600 U/ml) was able to augment the frequency of proliferating cells and NK effector cells when spleen cells of BALB/c nu/+ and BALB/c nu/nu were cultured for 7 days in the presence of IL 2. When IFN was present during the 7-day culture period, we again found an increase in proliferative and cytotoxic frequencies in cultures of spleen cells from nude mice, but in contrast, found a decrease in these frequencies in cultures of spleen cells from euthymic mice. Addition of irradiated (3000 R) spleen or thymus feeder cells from euthymic mice to the nu/nu cultures caused an inhibitory activity of IFN also on nu/nu cells. These data indicate that IFN can have both positive and negative regulatory effects on the in vitro growth and differentiation of mouse NK cells and that the inhibitory effects are mediated via T lymphocytes.
Acrosomal autoantigens of guinea pig sperm. I. The purification of an aspermatogenic protein, AP2.
Authors: Teuscher C , Wild G C , Tung K S
Published: December 2022

A soluble aspermatogenic autoantigen (AP2) capable of inducing experimental allergic orchitis (EAO) in the guinea pig has been isolated from the soluble acrosomal contents (SAC) released from guinea pig cauda epididymal sperm during the in vitro Ca+2 ionophore A23187-induced acrosome reaction. AP2 purification was achieved by heat inactivation of SAC enzymatic activity, followed by chaotropic solubilization and ultracentrifugation, gel filtration on Sephadex G-50, preparative isoelectric focusing, and SDS-polyacrylamide gel electrophoresis. Approximately 80 micrograms of AP2 was obtained from 1 to 2 x 10(10) cauda epididymal sperm. AP2 has a m.w. of 9500 +/- 1500 as determined by unreduced SDS-PAGE and an isoelectric point of 5.52 +/- 0.11. Amino acid analysis of AP2 indicates that it is a protein. AP2 has no detectable hexose or hexosamine as determined by gas liquid chromatographic analysis and is therefore probably not a glycoprotein. Five micrograms of AP2 are capable of inducing severe EAO in 100% of guinea pigs tested, whereas 0.5 to 2.0 micrograms induces mild lesions consisting primarily of aspermatogenesis in 66% of guinea pigs tested.
Phagocytosis of mast cell granules by cultured fibroblasts.
Authors: Subba Rao P V , Friedman M M , Atkins F M , Metcalfe D D
Published: December 2022

Cultured rat embryonic skin fibroblasts phagocytosed rat mast cell granules added to the medium or released from co-cultured mast cells by rabbit anti-rat IgE or Compound 48/80. Electron microscopy of fibroblasts incubated with mast cell granules revealed that granules adjacent to the plasmalemma were engulfed by long, thin cytoplasmic processes. Internalization proceeded to fusion of encircling processes and formation of phagosomes. Microtubules and 60 A microfilaments became closely associated with the phagosomal membrane to which small vesicles and cisternae of endoplasmic reticulum fused. The rate of uptake of mast cell granules by fibroblasts was dependent upon temperature and granule concentration. Cytochalasin B inhibited granule uptake whereas colchicine and nocodazole had little effect. Phagocytosis was not influenced by actinomycin D and cycloheximide, was partially inhibited by fluoride, and was markedly inhibited by cyanide, azide, and 2,4-dinitrophenol. Supernatants from fibroblast cultures incubated with mast cell granules for 24 and 48 hr, during which period phagocytosis occurred, contained elevated levels of collagenase and beta-hexosaminidase, but normal levels of lactate dehydrogenase and superoxide dismutase. These results support the concept that immediate hypersensitivity reactions are in part terminated by phagocytosis of biologically active discharged mast cell granules by resident connective tissue fibroblasts. Further, it is suggested that a consequence of this process is an alteration in fibroblast behavior, providing a unique link between immediate hypersensitivity reactions and connective tissue responses to inflammation.
Malignant rabbit fibroma virus causes secondary immunosuppression in rabbits.
Authors: Strayer D S , Skaletsky E , Cabirac G F , Sharp P A , Corbeil L B , Sell S , Leibowitz J L
Published: December 2022

Shope fibroma virus (SFV) causes a localized, self-limited, fibroblastic proliferation in adult rabbits. Extracts of Shope fibroma tumors were found to contain a second virus that induces a rapidly progressive disseminated tumor. Dissemination of this malignant fibroma is associated with activation of commensal mucosal infection with Pasteurella multocida, causing purulent conjunctivitis and rhinitis and resulting in death from nasal obstruction. We have isolated this new agent by two cycles of plaque purification. It is a poxvirus that is antigenically virtually identical to SFV as measured by a plaque reduction assay, but behaves differently both in vivo and in vitro. We have called this virus malignant rabbit fibroma virus (MV). Electrophoresis of restriction digests made with HIND III indicates that despite the antigenic similarity of SFV and MV, the locations of HIND III sites in the two viral genomes are quite different. These experiments have enabled us to determine that MV was present in small quantities in our initial uncloned stock of Patuxent strain SFV. Lymphocytes from rabbits bearing MV-induced tumors responded poorly to both B and T lymphocyte mitogens. This nonspecific immunologic dysfunction is evident at or before the time when metastases and Gram-negative infection develop, and it becomes more profound as the disease progresses. MV-induced tumors may provide a model for Gram-negative infection and decreased immunologic responsiveness associated with malignancies.
Lymphocyte function in experimental African trypanosomiasis. V. Role of antibody and the mononuclear phagocyte system in variant-specific immunity.
Authors: Dempsey W L , Mansfield J M
Published: December 2022

The role of parasite-specific antibody and the mononuclear phagocyte system (MPS) in immunity to the African trypanosomes was examined. For this study C57BL/10SnJ mice were infected with Trypanosoma rhodesiense clone LouTat 1.0. Infected mice were injected with 75Se-labeled LouTat 1.0 trypanosomes, and clearance from the blood upon reexposure was measured throughout the course of infection. Clearance of labeled organisms occurred only on or after day 5, which was the day of natural elimination of LouTat 1.0 from the blood. Clearance was dependent on a functional immune system and correlated with the appearance of antibody to the variant-specific surface antigen (VSSA) of the trypanosomes. The ability to clear trypanosomes was transferred to normal, uninfected mice by immune serum. Both the IgM and IgG fractions of immune serum mediated the clearance, and VSSA-specific IgM fractions were as efficient in clearing LouTat 1.0 as the IgG fractions. Normal levels of complement (C3) were not required for clearance. The liver was the primary organ of clearance, and the ability of the liver to sequester radiolabeled trypanosomes was not impaired in the terminal phase of the disease or by large numbers of circulating trypanosomes present representing different variant antigenic types (VAT). We conclude that in African trypanosomiasis the MPS is not depressed in its ability to clear trypanosomes of the infecting VAT at any time during the course of infection. The observed clearance function requires parasite-specific antibody but normal levels of C3.
The role of Ia molecules in the activation of T lymphocytes. II. Ia-restricted recognition of allo K/D antigens is required for class I MHC-stimulated mixed lymphocyte responses.
Authors: Rock K L , Barnes M C , Germain R N , Benacerraf B
Published: December 2022

The role of Ia molecules in the T cell proliferative response to class I (H2K/D) MHC alloantigens was examined. Proliferation in response to allo-K/D antigenic stimulation, but not to allo-Ia, was markedly inhibited by the addition of monoclonal anti-responder Ia antibodies to cultures in the absence of C. This anti-Ia blocking was observed in responses against both allelic and mutant class I antigens. Partial blocking was observed by using an anti-I-A or anti-I-E monoclonal antibody alone, whereas marked inhibition was seen with these two reagents together when the proliferating cells derived from a responder strain expressing both IA and IE gene products. Syngeneic Ia molecules appear to function as restriction elements, because they are required even in the presence of a source of exogenous second signal, phorbol myristic acetate or IL 1. The K/D-specific response required a responding cell that bears both Lyt-1 and -2 antigens, whereas responses generated to alloantigenic differences, including the I region, require only an Ly-1+ cell. The implications of these data with respect to the repertoire of the alloreactive proliferating T cell and the expression of the Lyt-2 antigen by such cells are discussed.
Expression of H-2Dd and H-2Ld mouse major histocompatibility antigen genes in L cells after DNA-mediated gene transfer.
Authors: Margulies D H , Evans G A , Ozato K , Camerini-Otero R D , Tanaka K , Appella E , Seidman J G
Published: December 2022

Among the more than 20 H-2-like genes in the BALB/c mouse genome, there are two classical transplantation antigens (H-2Dd and H-2Ld) encoded at the D-end of the major histocompatibility complex. Here we report the identification of a bacteriophage clone that encodes H-2Dd. The H-2Dd gene was identified by nucleotide sequence analysis and by characterization of the new H-2 antigen expressed when the cloned gene was introduced into mouse L cells by DNA-mediated gene transfer. The previously identified H-2Ld gene was then compared with the H-2Dd gene. The two genes appear to have the same general structure, and for the 854 nucleotides that have been compared, the two genes are 89% homologous. The H-2Ld and H-2Dd antigens expressed on mouse L cells after DNA-mediated gene transfer were examined by immunologic criteria. The stably transformed cell lines express apparently normal levels of H-2Dd and H-2Ld on the cell surface as measured by quantitative immunofluorescence by using monoclonal anti-H-2 antibodies. They synthesize H-2Dd and H-2Ld at normal rates as determined by endogenous labeling and immunoprecipitation of cell extracts. They evoke a strong specific serologic response when used to immunize C3H mice. The newly expressed antigens are able to serve as targets for alloreactive T cells. These cloned genes provide good substrates for examining the evolution of two closely linked H-2 antigen genes. Comparison of the structures of these genes provides clues to the basis for the differential expression of these antigens and their different biologic functions.
Inhibition of tumor growth by monoclonal anti-I-J antibodies.
Authors: Drebin J A , Waltenbaugh C , Schatten S , Benacerraf B , Greene M I
Published: December 2022

In this paper we have examined the effects of i.v. administered monoclonal anti-I-J antibodies on tumor growth in syngeneic and semi-syngeneic hosts. These antibodies inhibit tumor growth in mice bearing the appropriate I-J-encoded gene product on their lymphoid cells at nanogram dosages. The spleens of monoclonal anti-I-J-treated primary tumor-bearing mice do not contain transferable tumor-specific cells. These findings suggest that inhibition of suppressor cell function may be the mechanism by which anti-I-J antibodies inhibit tumor growth. We have also demonstrated that tumors growing in F1 hybrid mice are inhibited by monoclonal anti-I-J antibodies reactive with either parental haplotype and that there is no evidence of synergy when both antibodies are administered simultaneously. This may indicate that I-J molecules are codominantly expressed on a critical component of the F1 suppressor pathway.
Pretreatment with minor histocompatibility antigens prevents the development of functional CTL helper cell activity.
Authors: Hayes R L , Claman H N
Published: December 2022

We have been studying the regulation of allogeneic cytotoxic cells (CTL) in vivo. CBA/J (H-2k, mls d) responder mice are unable to develop CTL after an allogeneic footpad immunization if they are pretreated i.p. with spleen cells from either C3H/HeN (H-2k, mls c) or B10.BR (H-2k, mls b) mice. These mouse strain combinations are H-2 compatible but differ at the Mls and other minor histocompatibility loci. We reported that this state of CTL unresponsiveness is specific and that the allogeneic cells used for footpad immunization and the pretreatment strain must share both minor antigens and part of the MHC. In this paper, we describe some of the characteristic features of this CTL unresponsiveness. The CBA host plays an active role and appears to down-regulate its subsequent response against minor antigens after the initial pretreatment. This statement is based on the following: 1) The inhibition of in vivo CTL generation can be achieved by injecting F1 or irradiated C3H cells, i.e., under conditions where GVHD was not a factor; and 2) the state of unresponsiveness is abolished by host treatment with cyclophosphamide. In addition, we demonstrate that the lack of CTL development in pretreated responder animals is the result of impaired helper cell activity. Draining LNC from unresponsive mice can become functionally cytolytic if cultured in a Con A-activated spleen cell supernatant. However, normal CTL responses were not restored after adult thymectomy or splenectomy. Thus, the state of CTL inhibition that is induced by the minor antigen pretreatment is the result of a host-mediated regulatory circuit.
Role of the major histocompatibility complex in T cell activation of B cell subpopulations. Ir gene regulation of the T cell-dependent activation of distinct B cell subpopulations.
Authors: Asano Y , Singer A , Hodes R J
Published: December 2022

Antibody responses to (T,G)-A--L and (H,G)-A--L or to the TNP conjugates of these polypeptides, are regulated in the mouse by Ir genes encoded in the I-A subregion of the mouse MHC. To study the mechanism by which Ir genes function, it is essential to identify the cell interactions that are regulated by these genes. In the present report, it was specifically determined whether Ir gene function is expressed differently in the activation of B cell subpopulations that participate in two different pathways of B cell activation for in vitro antibody responses to TNP-(T,G)-A--L and TNP- (H,G)-A--L. The results of these studies demonstrate that under conditions that activate the Lyb-5- b cell subpopulation via MHC-restricted TH cell-B cell and TH cell-APC interactions, Ir gene function regulates TH cell interactions with these B cells as well as with APC. In addition, under conditions that activate the Lyb-5+ B cell subpopulation via MHC-restricted TH cell-APC but not TH cell-B cell interaction, Ir gene function regulates only TH cell interactions with APC but not with B cells.
Monoclonal antibodies with specificity for three different serotypes of Marek's disease viruses in chickens.
Authors: Lee L F , Liu X , Witter R L
Published: December 2022

A total of 50 antibody-secreting hybridoma cells against Marek's disease virus (MDV) and turkey herpesvirus (HVT) have been produced. Eleven hybridomas were used for serotyping a panel of 15 pathogenic and nonpathogenic strains of MDV and HVT, representing three serotypes. The antibodies from the culture medium have fluorescence antibody (FA) titers of up to 100 and those from mouse ascitic fluid have titers ranging from 10(4) to 10(6). Monoclonal antibody T81 is type-common, i.e., it reacts at equal titer with all MDV and HVT tested. Of the remaining 10 antibodies, eight react only with pathogenic and attenuated strains of MDV (presumably serotype 1), one reacts only with nonpathogenic MDV (presumably) serotype 2), and one reacts only with strains of HVT (presumably serotype 3). Two hybridomas belong to IgG2a and IgG2b subclasses, respectively, and the remaining nine belong to IgG1 subclass. None of the antibodies specific for MDV strains reacted with homologous viruses in serum neutralization (SN), agar gel precipitin (AGP), or membrane immunofluorescence tests. Antibody L78, which is specific for HVT, was reactive with its homologous virus in the SN test; antibody from the culture medium showed an SN titer of 10 and that from mouse ascites a titer of 10,000. None of the antibodies specific for MDV or HVT reacted with other avian or mammalian herpesviruses, avian leukosis viruses (ALV), reticuloendotheliosis viruses (REV), or Marek's disease tumor-associated surface antigen (MATSA) expressed in a lymphoblastoid cell line, MDCC-MSB-1.
Regulatory mechanisms in cytotoxic T lymphocyte development. I. A suppressor T cell subset that regulates the proliferative stage of CTL development.
Authors: Susskind B M , Merluzzi V J , Faanes R B , Palladino M A , Choi Y S
Published: December 2022

The alloantigen-induced suppressor function of cells from 3-day mixed leukocyte culture (MLC) was studied. These cells, when co-cultured with normal syngeneic lymphocytes and cells of the same haplotype as the original inducing alloantigen, inhibited the generation of cytotoxic T lymphocytes (CTL). Suppression was mediated by a radiation-resistant Lyt-2+ T cell. The suppressor T cells appeared to act by inhibiting the clonal expansion of CTL precursors in the responder cell population, determined by limiting dilution analysis. Levels of endogenous interleukin 2 (IL 2) in co-cultures with suppressor T cells were diminished, and the addition of exogenous IL 2 to co-cultures cancelled the suppressor T cell effects. The suppressor cell population was shown to be capable of absorbing IL 2 from lymphokine preparations, and in contrast to mitogen-induced suppressor T cells, after exposure to IL 2 the allostimulated suppressor T cell remains active. The results are discussed in terms of possible modes of action of the suppressor T cell.
Intramucosal lymphocytes of the gut: Lyt-2 and thy-1 phenotype of the granulated cells and evidence for the presence of both T cells and mast cell precursors.
Authors: Schrader J W , Scollay R , Battye F
Published: December 2022

The gut mucosa contains lymphocyte-like cells, a proportion of which contain a small number of granules that resemble those of mast cells in that they contain histamine and stain metachromatically. It has been suggested that these granulated lymphocytes represent transitional forms in the differentiation of T cells into mast cells. We used monoclonal antibodies and the fluorescence-activated cell sorter to analyze the expression of Thy-1 and Lyt-2 antigens on gut intramucosal lymphocytes with particular emphasis on the granulated cells. A minority of the granulated cells (10 to 20%) expressed Thy-1 antigen at high levels equivalent to those on cortical thymocytes. A much higher proportion of the granulated cells (about 90%) expressed readily detectable levels of Lyt-2 antigen and the most prevalent phenotype of the granulated lymphocytes (60 to 70%) was Lyt-2+, Thy-1-. Two operationally specific preparations of growth factors, one maintaining the proliferation of T cells and containing T cell growth factor, and the other containing a factor stimulating the growth of persisting (P) cells that are probably mast cell progenitors, were tested on lymphocytes from the gut mucosa. By using the appropriate preparation of growth factors, both T and P cells could be grown readily from the preparation of gut intramucosal lymphocytes. Estimates of the frequency of P cell precursors among these cells indicated a minimum of one in 300 could give rise to cells resembling mast cells. Fractions of Lyt-2+ cells that were enriched in granulated cells had few detectable P cell precursors, an observation lessening the likelihood that the granulated cells were progenitors of the P cells. The precise relationship of the granulated lymphocytes (mainly Lyt-2+, Thy-1-) to T cells remains to be established.
Expression of cell surface antigens by suppressor T cell hybridomas. I. Comparison of phenotype and function.
Authors: Trial J , Kapp J A , Pierce C W , Shreffler D C , Sorensen C M , Waltenbaugh C
Published: December 2022

The phenotypic expression of cell surface markers by T cell hybridomas that elaborate suppressor factors specific for the polymers L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) or L-glutamic acid50-L-tyrosine50 (GT) has been analyzed. We found that determinants encoded by the I-J subregion of the H-2 complex were borne on the surface of these hybrid cells and on the factors they secrete, whereas I-J determinants were not expressed by the AKR thymoma fusion parent, BW5147. The level of expression of I-J determinants fluctuated widely depending upon culture conditions, but I-J products and other cell surface markers of normal T cells could be quantitatively increased, or induced to appear, by treatment of the hybridomas with chemical agents, such as dimethyl sulfoxide (DMSO) or phorbol myristate acetate (PMA). In contrast, the surface expression of the viral product gp70 was decreased by the same treatment. Using chemical induction, we typed BW5147, a group of antigen-specific suppressor T cell hybridomas, and two control hybridomas for expression of I-J, Thy-1, Lyt, and H-2K alloantigens. Also, a haplotype-specific hybridoma that produces an antigen-nonspecific factor was analyzed. The results demonstrated that BW5147 failed to express I-J or Lyt alloantigens but expressed Thy-1.1 and H-2Kk gene products. The pattern of expression of these antigens by T cell hybridomas was very complex, but three conclusions could be drawn: 1) Good correlation exists between the expression of certain I-J determinants and the ability of T cell hybridomas to produce suppressor factor. 2) The expression of Thy-1, Lyt, or H-2Kk determinants is variable, and no correlation was found between expression of these antigens and the ability to produce active suppressor factors. 3) I-Jk products contributed by the AKR thymoma fusion partner are expressed by T cell hybridomas.