bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of monoclonal antibodies to Treponema pallidum.
Authors: Lukehart S A , Tam M R , Hom J , Baker-Zander S A , Holmes K K , Nowinski R C 
Published: December 2022

Abstract
Thirteen hybrid cell lines which produce mouse monoclonal antibodies to Treponema pallidum, the causative agent of syphilis, have been established. All of the monoclonal antibodies react with T. pallidum, Nichols strain, in ELISA and in immunofluorescence assays, but do not react with normal rabbit testicular tissue in the ELISA. Two of these antibodies were demonstrated to react with the nonpathogenic treponemes T. phagedenis, biotype Reiter, T. refringens (Noguchi strain), T. vincentii, and T. denticola (strains 11 and W), as well as with Borrelia recurrentis, Leptospira interrogans, serogroup Canicola, and the swine pathogen T. hyodysenteriae. The remaining 11 antibodies react with four recently isolated strains of T. pallidum, but with none of the related nonpathogens nor with Borrelia or Leptospira. Thus, our results to date indicate that these monoclonal antibodies may identify antigenic determinants that are specific either for T. pallidum alone or for those treponemes which are pathogenic for humans. The molecular specificities of six of the 13 antibodies were determined by Western blotting. We anticipate potential usefulness of these antibodies in the investigation of the antigenic structure of T. pallidum, the taxonomic study of the pathogenic and nonpathogenic treponemes, and in the diagnosis of syphilis.
B cell subsets in spleens of BALB/c mice: identification and isolation of MMTV-expressing and MMTV-responding subpopulations.
Authors: Lopez D M , Charyulu V , Paul R D 
Published: December 2022

Abstract
The DNA of BALB/c mice contains two genomic- and one subgenomic-size MMTV proviruses that appear to be preferentially expressed in their spleen cells, although intact MMTV virions cannot be detected in the tissues of these mice. This retrovirus antigen expression is restricted to a subpopulation of B lymphocytes, as determined by double label immunofluorescence studies. Nylon-adherent, SIg-positive spleen lymphocytes from BALB/c mice are capable of being stimulated by purified MMTV in lymphocyte transformation assays. Two possibilities were explored: the MMTV-positive cells are the responders to MMTV in the blastogenesis assay, or there exists two B lymphocyte subsets, one expressing the MMTV antigen(s) and the other responding to the virus. Depletion of MMTV-positive, nylon-adherent cells with anti-MMTV and complement resulted in no significant change in the blastogenesis to MMTV, indicating that the MMTV-negative lymphocytes are the responders in this reaction. These results were confirmed by positive selection experiments by using a fluorescence-activated cell sorter. Two populations of nylon-adherent cells, on the basis of the presence or absence of MMTV antigen in their surfaces, were obtained by a two-way sorting procedure and were used in lymphocyte transformation assays. MMTV-expressing lymphocytes were found to be nonresponsive to MMTV antigens, although high levels of [3H]thymidine incorporation were observed in the MMTV-negative, nylon-adherent cell cultures exposed to MMTV. These data indicate that in normal BALB/c mice, expression of endogeneous retrovirus genetic information is restricted to a nylon-adherent spleen cell subset that is different from the one responding in blastogenesis to the viral antigens.
Functional analysis of mononuclear cells infiltrating into tumors: differential cytotoxicity of mononuclear cells from tumors of immune and nonimmune rats.
Authors: Ibayashi Y , Uede T , Uede T , Kikuchi K 
Published: December 2022

Abstract
A million syngeneic gliosarcoma (T-9) cells injected subcutaneously are sufficient to kill Fisher rats within 2 mo. Fisher rats became resistant to T-9 cells by surgical removal of the implanted tumor and repeated immunization with MMC-treated T-9 cells. Histopathologic studies revealed massive accumulation of mononuclear cells in tumor tissues of immune rats that were rejecting syngeneic T-9 tumors, whereas very few mononuclear cells were found in tumor tissues of nonimmune rats. Cell populations infiltrating into tumor tissues were identified by immunohistochemical techniques. Mononuclear cells found within the regressing tumors of immune rats were identified mostly to be T cells, and two-thirds of these T cells were OX-8 positive. In contrast, mononuclear cells found within the growing tumors of nonimmune rats were identified to be mixtures of macrophages and T cells, and very few OX-8 positive cells were found. Mononuclear cells were isolated from implanted T-9 tumors to determine whether mononuclear cells lysed T-9 cells specifically. Significant tumoricidal activity was seen when mononuclear cells from tumors of immune rats were used, whereas no detectable tumoricidal activity was observed with mononuclear cells from tumors of nonimmune rats. Winn assays confirmed in vitro 51Cr release assays by showing that tumors were rejected only when T-9 cells were implanted into normal Fisher rats along with mononuclear cells from tumors of immune rats.
Monoclonal helper T cells induce B cell responses to T-independent antigens: antigen-specific T cells are directly stimulated by activated B cells in the absence of antigen.
Authors: DeKruyff R H , Clayberger C , Cantor H 
Published: December 2022

Abstract
Efficient B cell responses to most polysaccharide antigens such as TNP-PAA or TNP-Ficoll require factors produced by activated T cells. However, the mechanism of T cell activation during such responses has not been established, because these antigens do not activate T cells, either directly or in conjunction with I-A gene products. We used a panel of antigen-specific monoclonal helper T cells to study T cell activation during the course of such responses. We show that activated I-A-identical B cells directly stimulate these monoclonal T cells, and that this stimulation is in the absence of nominal antigen. The high frequency of inducer cells that are stimulated by activated B cells suggests a major biologic role for this novel pathway of T cell activation.
Development and distribution of B lineage cells in the domestic cat: analysis with monoclonal antibodies to cat mu-, gamma-, kappa-, and lambda-chains and heterologous anti-alpha antibodies.
Authors: Klotz F W , Gathings W E , Cooper M D 
Published: December 2022

Abstract
To trace the development and distribution of B lineage cells in the domestic cat (Felis catus), we have produced monoclonal antibodies against mu-, gamma-, kappa-, and lambda-chains of feline immunoglobulins (Ig). Goat antibodies against human mu-, alpha-, and lambda-chains, which are reactive with shared determinants on their feline counterparts, were used in conjunction with the panel of mouse monoclonal antibodies. Cytoplasmic mu+ pre-B cells and surface IgM+ B lymphocytes were observed in 42 day fetal liver in which pre-B cells were more abundant than IgM+ B cells. Pre-B cells also were found in bone marrow in young cats, and continued to be generated in the marrow throughout life. In the spleen, adult levels of B cells were attained by 12 wk of age, at which time the frequencies of surface IgM+, IgG+, and lambda+ cells were 49, 3, and 40%, respectively. The distributions of Ig isotypes also were determined among plasma cells as a function of age and tissue localization. IgM plasma cells were predominant in the bone marrow of 1-wk-old cats, whereas IgG plasma cells were the prevalent isotype in adult bone marrow. In the mesenteric lymph nodes of adult animals, the frequency distributions of IgM, IgG, and IgA plasma cells were similar to the frequency distributions of IgM, IgG, and IgA isotypes among bone marrow plasma cells. IgA+ plasma cells predominated in the intestinal lamina propria, in which IgG+ and IgM+ plasma cells were relatively infrequent. In the tissues of both young and adult animals, the ratio of lambda:kappa expression was approximately 3:1. We conclude that the pattern of B cell development in the cat resembles that found in other mammals, except that the kappa to lambda ratio is reversed.
Stimulated rat T cell-derived inhibitory factor for cellular DNA synthesis (STIF). II. Kinetics of the production and characterization of the producer.
Authors: Chiba K , Nishimura T , Hashimoto Y 
Published: December 2022

Abstract
Kinetics of the production of a stimulated T cell-derived inhibitory factor for cellular DNA synthesis (STIF) (1) from Con A-stimulated SD rat spleen cells, and the cells involved in the production of the factor, were examined comparatively with those of interleukin 2 (IL 2) and interferon (IFN). STIF activity in the culture supernatants reached a plateau 24 hr after the culture, and the plateau level was maintained during an additional culture for 72 hr. Characterization of the cells involved in STIF production by means of negative selection of unfractionated or nylon-fractionated spleen cells with anti-rat T cell serum or monoclonal antibodies plus complement revealed that the cells are nylon-nonadherent T cells bearing a suppressor T cell marker. The nylon-nonadherent T cell population did not require additional macrophages for STIF production. In vivo pretreatment of rats with cyclophosphamide (25 to 100 mg/kg) reduced or abolished the production of STIF from the Con A-stimulated spleen cells of the rats. The STIF production from Con A-stimulated spleen cells was inhibited by the addition of indomethacin at 10 ng/ml, indicating a regulatory role of prostaglandin(s) in STIF production. The above characteristics distinguish a T cell subset for STIF production from those for IL 2 and IFN production.
Biosynthesis of mouse Thy-1 antigen.
Authors: Luescher B , Bron C 
Published: December 2022

Abstract
The biosynthesis and the maturation of Thy-1 antigen of mouse thymocytes have been studied by using a xenogeneic rabbit anti-mouse Thy-1 antibody. The earliest form of Thy-1 detected after a 5-min pulse with [35S]methionine and [35S]cysteine had an apparent m.w. of 26,500. During chase, this band converted to a molecular ratio (Mr) = 25,000 polypeptide, probably derived from the latter by trimming of glucose or mannose residues from the three high-mannose glycan units of Thy-1. Mature Thy-1 molecules were detected at the cell surface after a 15-min chase. At least one of the three N-linked oligosaccharide units was shown to be in the high mannose form at the cell surface, as indicated by its susceptibility to endo-beta-N-acetylglucosaminidase H digestion. Treatment of the early and late forms of Thy-1 antigen with endo-beta-N-acetylglucosaminidase F generated a single polypeptide of Mr = 13,500. The same precursor was obtained when cells were labeled in the presence of tunicamycin. This indicates the absence of O-linked glycan in the mature cell surface antigen. Finally, the resistance of Thy-1 antigen to trypsin digestion when associated with membranes confirmed that this molecule has no cytoplasmically oriented portion.
Isolation of rabbit C3, Factor B, and Factor H and comparison of their properties with those of the human analog.
Authors: Horstmann R D , Müller-Eberhard H J 
Published: December 2022

Abstract
The rabbit complement components C3, Factor B, and Factor H were isolated and characterized and were compared to the corresponding proteins of human serum. Chromatographic behavior, chemical properties, and functional interactions show great similarities between the components in both species. By SDS polyacrylamide gel electrophoresis, the m.w. were estimated to be 195,000 for C3, 86,000 for Factor B, and 155,000 for Factor H. The amino acid compositions of the rabbit proteins resembled those of the human analog. The total carbohydrate content of rabbit C3 and Factor H was approximately one-half that of the human proteins. In addition, a qualitative difference in the carbohydrate moieties of the C3 proteins was observed. The serum concentration of the rabbit proteins was markedly lower than that of the human proteins. The rabbit C3b,Bb enzyme resembled the human analog with respect to half-life, control by Factor H, and stabilization by nickel ions.
Complement-mediated hemolytic activity of succinylated concanavalin A: preparation and activity of cell intermediates.
Authors: Langone J J , Ejzemberg R 
Published: December 2022

Abstract
Succinylated concanavalin A (SCon A) lyses sheep erythrocytes (E) in the presence of complement, whereas the native tetravalent lectin, Con A, is inactive. We have studied the ability of E-SCon A (ES) to interact with early acting guinea pig (gp) or human (hu) complement components (C1, C2, C4) and found that cell intermediates ESC1, ESC4, ESC14, and ESC142 can be generated that are analogous to intermediates conventionally prepared with E and rabbit IgM (pentameric) anti-Forssman antibody. Titration of gp or hu C1, C4, and C2, and quantification of the number of activated C1 molecules bound to ESC4 by the C1 fixation and transfer test showed in each case that an average of one effective site per cell was sufficient to cause cell lysis. Determination of tmax for optimal formation of ESC142 sites depended on the species combination of components used to make the intermediates, and the decay of ESC142 and EAC142 sites or sites generated with ESC4, EAC4, and trypsin-activated C2 were similar. The sugar alpha-D-methylglucopyranoside (alpha-MGP) inhibited binding of SCon A to E and eluted the lectin from ES, whereas galactose was nearly inactive, consistent with lectin sugar-binding selectivity. In contrast, both sugars were ineffective in eluting SCon A or C4hu from ESC4hu, indicating that C4hu blocked the interaction between lectin and alpha-MGP, perhaps by steric hindrance. SCon A is a divalent functional analogue of IgM anti-Forssman antibody that may be a uniquely suited reagent specific for cell membrane glycoconjugates for studying the mechanism of binding and activation of complement components.
Modulation of cytoplasmic calcium in human platelets by the phospholipid platelet-activating factor 1-O-alkyl-2-acetyl-SN-glycero-3-phosphorylcholine.
Authors: Valone F H , Johnson B 
Published: December 2022

Abstract
The calcium-sensitive, fluorescent dye Quin 2 was used to quantitate changes in free intracellular calcium [( Ca2+]i) induced in platelets by the phospholipid platelet-activating factor 1-O-alkyl-2-acetyl-SN-glycero-3-phosphorylcholine (AGEPC). The Ca2+]i of unstimulated platelets was 91 +/- 18 nM (mean +/- SD, n = 8), and treatment with 1 to 16 nM AGEPC increased [Ca2+]i in a dose-related manner, with 16 nM AGEPC increasing [Ca2+]i by 102 +/- 20 nM. [Ca2+]i was not increased by analogs of AGEPC which do not activate platelets including the lysophospholipid precursor of AGEPC, the optical isomer, and a C-2 benzoyl analog. The capacity of AGEPC to increase [Ca2+]i exceeded that required to induce maximal platelet aggregation. In four experiments, 100% platelet aggregation was induced by 4.5 +/- 2.4 nM AGEPC (mean +/- SD) and was associated with a submaximal increase in [Ca2+]i of 56 +/- 22 nM. Pretreatment of platelets with AGEPC rendered the platelets specifically unresponsive to repeat stimulation with AGEPC in terms of both platelet aggregation and increased [Ca2+]i, whereas the platelet response to thrombin was undiminished by pretreatment with AGEPC. In contrast, the platelet response to 0.5 microM calcium ionophore A23187 was undiminished by pretreatment with the same concentration of ionophore, suggesting that AGEPC does not activate platelets by an ionophore-like mechanism. IgG aggregates and AGEPC in combination activate platelets synergistically, as shown by the observation that a 1-min exposure of platelets to 60 micrograms/ml of IgG aggregates increased the platelet aggregation response to 2 nM AGEPC from 44 to 100%. In contrast, sequential exposure of platelets to IgG aggregates and AGEPC increased [Ca2+]i additively, suggesting that increased [Ca2+]i contributes to but does not fully mediate synergistic platelet activation by IgG aggregates and AGEPC. Quantitation of free intracellular calcium with the fluorescent dye Quin 2 is a highly sensitive technique for delineating the role of calcium in mediating platelet activation.
Effect of antibodies directed against complement receptors on phagocytosis by polymorphonuclear leukocytes: use of iodination as a convenient measure of phagocytosis.
Authors: Klebanoff S J , Beatty P G , Schreiber R D , Ochs H D , Waltersdorph A M 
Published: December 2022

Abstract
Two monoclonal antibodies (Mab), designated 60.3 and 60.1, markedly inhibited the phagocytosis of serum-opsonized zymosan by human polymorphonuclear leukocytes (PMN) as measured by the iodination reaction and by microscopic visualization. These antibodies also inhibited rosette formation with EC3bi without decreasing EC3b rosetting, suggesting that Mab 60.3 and 60.1 inhibit the phagocytosis of opsonized zymosan through reaction with the C3bi receptor (CR3) on the leukocyte surface. In support of this concept is the finding that the PMN of two patients with recurrent infections do not ingest opsonized zymosan, lack C3bi receptor function, and react weakly or not at all with Mab 60.3 and 60.1. At concentrations which completely inhibited ingestion of opsonized zymosan, both Mab partially inhibited iodination with Staphylococcus aureus 502A as the particle, and did not affect iodination when Staphylococcus epidermidis was used. This presumably reflects a variable need among the opsonized particles for CR3 for ingestion. Mab 60.3 also inhibited the phagocytosis of certain unopsonized particles as measured by iodination, indicating that the antigens recognized by the Mab do not influence phagocytosis solely by functioning as a C3bi receptor. Mab 60.3 increased the phagocytosis of unopsonized, heat-killed S. aureus by reaction with the PMN via its antibody-combining site, and with the staphylococcal protein A via its Fc region (reverse opsonization). This process required protein A-containing organisms (S. aureus 502A or Cowan 1 but not S. aureus Wood 46 or S. epidermidis), was inhibited by purified protein A, and was not seen either when the F(ab')2 or Fab fragments of the antibody, or when PMN which lack or have low levels of the antigen were employed. Thus, these studies, using iodination as a convenient method for the measurement of phagocytosis, demonstrated two effects of antibodies directed against PMN cell surface components: inhibition of phagocytosis by reaction with the C3bi receptor, and stimulation of phagocytosis by reverse opsonization.
Effect of glucocorticoids on the development of suppressive activity in human lymphocyte response to a polysaccharide purified from Candida albicans.
Authors: Piccolella E , Vismara D , Lombardi G , Guerritore D , Piantelli M , Ranelletti F O 
Published: December 2022

Abstract
The action of glucocorticoids on the proliferative response of human lymphocytes stimulated in vitro by MPPS has been investigated. The effect of Dex was dependent on the time of steroid addition to the cultures. Dex added at the beginning of the culture period inhibited, cell proliferation and IL 1/IL 2 synthesis, although not completely. However, a delayed addition of 24 to 48 hr resulted in an enhancing effect on cell proliferative responses that was maximal at day 4. The effect of Dex on T suppressor cell activity was then investigated. Dex added 1 day before the appearance of suppressor cells resulted in a marked decrease or disappearance of the suppressive activity. Moreover, primed T lymphocytes treated with Dex in the presence of exogenous IL 2 enhanced the proliferative responses of fresh autologous PBMC stimulated by MPPS. Taken together, our data suggest that glucocorticoids inhibit the differentiation of T suppressor cells and that IL 2 is unable to reverse this inhibitory effect.
Mouse IgD half molecules with shortened IgD heavy chain result from alterations within C delta locus.
Authors: Thiele C J , Owens J D , Finkelman F D , Mushinski J F 
Published: December 2022

Abstract
An unusually small (51 KD) IgD myeloma protein was isolated from secretions of TEPC 1017 generation (gen) 24. The delta-chain mRNA and the delta-chain gene in this tumor were compared with those of TEPC 1017 of earlier generations. The gen 24 protein contained one normal-sized kappa-type light chain (21 KD) and one unusually short delta-heavy chain (30 KD). The delta-heavy chain was 15 KD shorter than that of TEPC 1017 of earlier generations, owing to a delta-mRNA (1.15 kb) which was 600 bp shorter than that of TEPC 1017 of earlier generations. TEPC 1017 is a tetraploid tumor, and the gen 24 appears to contain at least two different deletions on different chromosomes. The short mRNA was produced from one of these altered delta-chain genes which had a productive VDJ rearrangement but which had lost the C delta 3 domain and perhaps the C delta H domain as well. Despite these genetic insults, RNA splicing produced delta-mRNA with secreted termini and mRNA with membrane-binding termini. It is suggested that the mouse C delta gene has an unusual predilection for deletions because it normally lacks any vestige of C delta 2 and, during i.p. passage, it suffered further deletions or alterations.
Lymphokine-activated tumor inhibition in vivo. I. The local administration of interleukin 2 triggers nonreactive lymphocytes from tumor-bearing mice to inhibit tumor growth.
Authors: Forni G , Giovarelli M , Santoni A 
Published: December 2022

Abstract
CE-2 is a chemically induced tumor of low immunogenicity in syngeneic BALB/c mice. Nylon wool columns eluting lymphocytes from the spleen of mice bearing clinically evident (5-mm mean diameter) CE-2 tumors (CE-2 TB lymphocytes) do not react with CE-2 cells in vitro, nor are they able to affect their growth in vivo in a Winn-type neutralization assay at 5:1 lymphocyte:tumor cell ratio. However, they become able to inhibit CE-2 tumor growth when 20 U of interleukin 2 (IL 2) in 0.4 ml are injected daily for 10 days at the challenge site. In contrast, mice injected with CE-2 cells and IL 2 only display tumor takes and growth that are not significantly different from those in controls challenged with CE-2 cells alone. This lymphokine-activated tumor inhibition (LATI) is not a peculiarity of the CE-2 tumor-host combination, because different tumors can be inhibited in this way and various TB lymphocytes can initiate it. In these experiments, IL 2-rich 25,000 to 30,000 m.w. fractions were obtained routinely from the culture supernatants of a clone of EL-4 thymoma stimulated with phorbol myristic acetate. Equally active IL 2-rich preparations were obtained from rat spleen cells stimulated with concanavalin A, or from MLA 144 gibbon lymphosarcoma spontaneously releasing IL 2. Treatment of CE-2 TB lymphocytes with various antibody and C, with 2000 rad gamma-irradiation, or fractionation on Percoll density gradients suggested that radioresistant functions of Thy-1.2+, Lyt-1.2+, Lyt-2.2- and of asialo GM1+ cells are independently involved in LATI induction. These lymphocytes inhibit tumor growth by recruiting the radiosensitive effector mechanisms of the recipient mice required for ultimate tumor destruction. CE-2 tumor inhibition by LATI leaves a specific delayed-type hypersensitivity and an immunologic memory, resulting in rejection of a second lethal CE-2 challenge in a significant number of mice.