bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical models of gamma-interferon action: altered expression of transferrin receptors on murine peritoneal macrophages after treatment in vitro with PMA or A23187.
Authors: Weiel J E , Adams D O , Hamilton T A
Published: December 2022

The number of transferrin receptors in thioglycollate-elicited murine peritoneal macrophages is markedly depressed after exposure to murine gamma-interferon (IFN gamma) in vitro. This change has been used as a model system to study the molecular and cellular mechanisms of IFN gamma signal transduction. We observed that the downshift of the transferrin receptor could be mimicked by exposure to the calcium ionophore (A23187) or the potent tumor promoter, phorbol 12-myristate 13-acetate (PMA). Saturation binding studies on thioglycollate (TG)-elicited peritoneal macrophages after exposure to A23187 or PMA showed the reduced expression of transferrin binding activity attributable to a decrease in the total number of cellular transferrin receptors and not an alteration in receptor-ligand affinity, in agreement with previous results obtained after exposure to IFN gamma. The loss of transferrin receptors in response to A23187 or PMA was dose dependent, and the kinetics of the change were identical to those observed with IFN gamma treatment. Phorbol 12,13-dibutyrate or 4-beta-phorbol 12,13-didecanoate, both biologically active phorbol esters, also induced reduced expression of transferrin receptors, whereas nonesterified phorbol or 4-alpha-phorbol 12,13-didecanoate, an inactive phorbol ester, had no effect on transferrin receptor expression. Finally, PMA and A23187, when used together, acted cooperatively to modulate transferrin receptor expression when both agents were present at subthreshold concentrations. These results, taken together, suggest that elevation of intracellular Ca++ levels and/or stimulation of protein kinase C are involved in the response of macrophages to IFN gamma.
Studies on the synthesis and secretion of interleukin 1. I. A 33,000 molecular weight precursor for interleukin 1.
Authors: Giri J G , Lomedico P T , Mizel S B
Published: December 2022

Previous studies have suggested that murine interleukin 1 (IL 1) may be synthesized as a high m.w. precursor. Using specific antibodies against murine IL 1, we have analyzed the primary form of IL 1 synthesized by normal peritoneal macrophages and P388D1 cell line macrophages, and in vitro using poly (A)+ RNA from stimulated normal and cell line macrophages. In all cases, the labeled protein immunoprecipitated with the anti-IL 1 antibodies exhibited a m.w. of 33,000 on SDS gels. This 33,000 m.w. protein was not an aggregate of low m.w. IL 1. Addition of excess purified low m.w. IL 1 completely blocked the immunoprecipitation of the 33,000 m.w. protein. When cells were pulsed with [35S]methionine for 1 to 5 hr and then incubated in medium containing unlabeled methionine for 19 hr, labeled low m.w. IL 1 was detected in the culture fluid. If cells were pulsed with [35S]methionine to label the 33,000 m.w. protein and then incubated in the presence of a maximally effective concentration of the protein synthesis inhibitor, cycloheximide, the low m.w. IL 1 was still found in the culture fluid. Our results indicate that IL 1 is synthesized as a 33,000 m.w. precursor that is converted to the low m.w. form that is found in the culture fluid of stimulated murine macrophages.
Identification and characterization of a B cell growth inhibitory factor (BIF) on BCGF-dependent B cell proliferation.
Authors: Kawano M , Iwato K , Kuramoto A
Published: December 2022

The culture supernatants of Con A-activated human peripheral blood mononuclear cells (PBM) contained at least two regulatory factors upon B cell proliferation. One was B cell growth factor (BCGF), which activated antigen-stimulated B cells to proliferation and clonal expansion, and the other was its inhibitory factor, arbitrarily named B cell growth inhibitory factor (BIF). This BIF inhibited the effect of BCGF on anti-mu-stimulated B cells or the monoclonal mature B cell line (CLL-T.H.) obtained from the peripheral blood lymphocytes of B cell-type chronic lymphocytic leukemia patients, which were activated only with BCGF and without adding other proliferating stimuli (e.g., anti-mu). BIF activity was detected in the 24 hr culture supernatants of Con A-activated human PBM in FCS containing medium and also in serum-free RPMI 1640 medium. This substance with BIF activity could not be derived from FCS. Con A-induced BIF (m.w. of 80,000 and an isoelectric point of pH 5.4) was analyzed by Sephadex G-200 gel filtration and chromatofocusing. BIF was stable at pH 2.0 and at 56 degrees C for 30 min. Partially purified BIF had no effect on cell viability and almost no interferon activity (less than 1 IU/ml). BIF with high titer had a slight but significant inhibition on TCGF-dependent T cell growth and on PHA or Con A responses, but the extent of these inhibitions was far less than that of BCGF-dependent B cell growth. Absorption of BIF with Con A blasts made its inhibition on T cell growth even less. On the other hand, BIF activity could not be absorbed with Con A blasts but was almost absorbed with large numbers of CLL-T.H. cells. BIF had almost no inhibitory effect on the proliferation of a mouse fibroblast cell line (NIH 3T3), a mouse myeloma cell line (NS-1), human lymphoid cell lines (MOLT-4, HSB-2, and Daudi), or a human myeloid cell line (K-562). BIF-producing cells were estimated to be T cells and were identified as T8+ T cells. On the other hand, Con A-induced BCGF was demonstrated to be produced predominantly by T4+ T cells. These results show that human B cell proliferation is regulated by interaction between T4+ and T8+ cells via soluble factors, namely BCGF and BIF, respectively.
Lymphokine-mediated induction of cytolytic activity in a T cell hybridoma.
Authors: Kanagawa O , Chiller J M
Published: December 2022

Functionally inducible CTL hybridomas were constructed by fusing alloantigen-specific T cells (C57BL/6 alpha-DBA/2) with cells from the rat thymoma line W/FU (C58NT)D. A cloned hybridoma line (KSH.4.13.6) that was specifically cytolytic in the presence of activated rat spleen cell supernatant fluid (rat Con A SN) lost activity when transferred to normal medium. However, a cytolytic activity could be reinduced by culturing KSH.4.13.6 cells in medium containing rat Con A SN or secondary mixed leukocyte culture SN. By using various sources of SN, it was found that cytolytic induction required two different factors. PMA-induced EL-4 SN and SN from antigen-activated cloned T cells, neither of which were capable of inducing cytolytic activity alone, were able to synergize in the cytolytic induction of KSH.4.13.6 IFN-gamma and IL 1 failed to induce cytolytic activity even in the presence of EL-4 SN. Furthermore, this hybridoma produced macrophage activating factor (MAF) upon culture in rat Con A SN, although MAF production could not be induced by either specific antigen or lectins. The kinetics of induction and loss of cytolytic activity mediated by rat Con A SN were similar to those of the induction of MAF production. However, EL-4 SN, which by itself was incapable of inducing cytolytic activity, was able to induce MAF production in the KSH.4.13.6 hybrid to an extent similar to that induced by rat Con A SN. These results suggest that the induction of cytolytic activity and of MAF production in this cloned hybridoma cell line are regulated by different mechanisms. Such a functionally inducible T cell hybrid may provide a tool for biochemical and molecular analysis of T cell function and regulation, and of the characterization of cytokines required for CTL differentiation.
Activation of the human classical complement pathway by a mouse monoclonal hybrid IgG1-2a monovalent anti-TNP antibody bound to TNP-conjugated cells.
Authors: Couderc J , Kazatchkine M D , Ventura M , Duc H T , Maillet F , Thobie N , Liacopoulos P
Published: December 2022

A mouse hybridoma selected and cloned for anti-TNP specificity produced three distinct monoclonal antibody species that were separated on protein A-Sepharose by stepwise acid elution. The IgG1 kappa product of the parental myeloma was eluted at pH 6.0. An IgG2a kappa bivalent anti-TNP antibody was eluted at pH 4.5, whereas elution at pH 5.0 yielded a hybrid IgG1-2a kappa monovalent anti-TNP antibody. The IgG2a molecules agglutinated TNP-conjugated sheep erythrocytes (TNP-ES) and lysed TNP-ES in the presence of normal human serum (NHS). Hybrid IgG1-2a antibody was also capable of lysing the cells in NHS, although it did not agglutinate TNP-ES. A threshold in monovalent antibody input was necessary for the lysis of TNP-ES, indicating a requirement for a minimal density of bound monovalent IgG to trigger complement activation. Lysis occurred in NHS-VBS++ but not in NHS-MgEGTA, and it was associated with a dose-dependent consumption of C1, C4, and C2 hemolytic activities. Quantitation of the antibody bound to TNP-ES when using radiolabeled rabbit anti-mouse Fab antibody demonstrated that for similar inputs, 5.4 times as much bivalent as monovalent antibody bound to TNP-ES. When similar amounts of antibody were effectively bound to TNP-ES, monovalent hybrid IgG1-2a was five times less efficient than bivalent IgG2a to yield 50% cell lysis in the presence of NHS. These results indicate that neither bivalent binding nor the presence of two identical heavy chains are necessary requirements for antibody-dependent activation of the classical complement pathway.
Human C3a-mediated suppression of the immune response. I. Suppression of murine in vitro antibody responses occurs through the generation of nonspecific Lyt-2+ suppressor T cell.
Authors: Morgan E L , Thoman M L , Weigle W O , Hugli T E
Published: December 2022

C3a derived from the third component of human complement was found to suppress in vitro murine anti-SRBC responses. C3a-mediated suppression occurs through the generation of nonspecific Lyt-2+ suppressor T cells. The generation of suppressor cells occurs at an early phase in the response because incubation of naive T cells with C3a for as little as 30 min results in suppression of the anti-SRBC response. The generation of suppressor T cells requires the interaction of T cells, C3a, and a Sephadex G-10-adherent cell, presumably a macrophage. Although the mechanism of action of these suppressor cells has not been elucidated, several possibilities have been eliminated. C3a-suppressor T cells do not apparently release inhibitory lymphokines, nor is helper cell activity inhibited by a 2-day co-culture with these suppressor cells. The observation that interleukin 2 (IL 2)-containing lymphokine preparations could overcome C3a-induced suppression led us to investigate the interaction of the suppressors with IL 2 producer cells. However, neither C3a nor C3a-generated suppressor T cells can block the synthesis of IL 2.
Characterization of the effects of phorbol esters on rat mast cell secretion.
Authors: Heiman A S , Crews F T
Published: December 2022

When applied to the skin, phorbol esters (PEs) elicit signs of acute inflammation, suggesting they may induce the release of mediators from mast cells. Therefore, we have studied the effects of PEs on purified rat peritoneal and thoracic mast cells both alone and in conjunction with the calcium ionophore, A23187, and various other secretagogues that interact with immunoglobulin E (e.g., anti-IgE and Con A) or other cell surface receptors, e.g., somatostatin and compd 48/80. PEs alone caused little or no release of histamine. However, the PE 12-O-tetradecanoylphorbol-13-acetate (TPA, 10 ng/ml) tremendously potentiated release induced by the calcium ionophore A23187, reducing the EC50 for A23187 from 832 ng/ml to 56 ng/ml. In the presence of suboptimal A23187 (50 ng/ml), only active tumor promoting PEs elicited histamine release. The EC50 values of the various active PEs were: TPA 5 ng/ml; 4 beta-PDD, 83 ng/ml; and 4-O-methyl-TPA, 807 ng/ml, with maximal histamine release ranging from 54 to 80%. TPA synergistically enhanced stimulation of histamine release by anti-IgE and Con A over the entire concentration-response range. In contrast, this synergism was absent when cells were stimulated with somatostatin and compd 48/80. Phorbol esters may act by increasing the activity of a calcium/phospholipid-dependent protein kinase (Ca/PL-PK). Mast cells do have Ca/PL-PK activity, and TPA in the presence of suboptimal A23187 induces protein phosphorylation comparable with other secretagogues. These results suggest that in the purified mast cell, PE-induced mediator release increases the sensitivity of release mechanisms for calcium, acts syngergistically with secretagogues interacting with IgE, and as suggested from structure-activity relationships, occurs via a specific mechanism of action perhaps involving the Ca/PL-PK.
Identification of an antigen specific to Trypanosoma congolense by using monoclonal antibodies.
Authors: Parish N M , Morrison W I , Pearson T W
Published: December 2022

Using indirect immunofluorescence assays on acetone-fixed smears of a series of different parasites, we have shown that two monoclonal antibodies bind specifically to Trypanosoma congolense organisms. The antibodies bind to both bloodstream trypomastigotes and procyclic culture forms of the parasite and are thus not stage specific. Immunoprecipitation and immunoblot analysis showed that both monoclonal reagents bound a protein of approximately 31,000 m.w. This antigen appeared to be located on the plasma membrane of T. congolense, but the epitope was not exposed on the surface of living bloodstream or procyclic organisms. The antigen was detectable on acetone-fixed organisms or in trypanosome lysates in enzyme-linked immunosorbent assays and may therefore by useful as a species-specific marker in field assays for epidemiologic and clinical investigations.
Mechanism of recovery from acute virus infection. I. Role of T lymphocytes in the clearance of lymphocytic choriomeningitis virus from spleens of mice.
Authors: Lehmann-Grube F , Assmann U , Löliger C , Moskophidis D , Löhler J
Published: December 2022

Adult mice were infected by i.v. inoculation with 10(3) mouse infectious doses of lymphocytic choriomeningitis virus (LCM virus). Despite widespread replication of the agent, overt illness did not develop; histopathologic alterations were moderate. High virus concentrations were attained in the spleen, which was chosen for further study. Cytotoxic spleen T cell responses were found to vary among inbred mouse strains, and as a rule, these were correlated with other virus-specific cell-mediated immune phenomena. However, high- and low-responder mice eliminated the virus equally fast and already at times when spleen cytotoxic T lymphocytes were just beginning to appear (and before delayed-type hypersensitivity could be demonstrated). Adoptive transfer experiments showed that very few immune T lymphocytes were capable of reducing virus replication in the recipients' spleens and, furthermore, that protection was rapidly induced; when low numbers of cells were transferred, the effect was apparent 8 hr later, and with higher numbers diminished virus replication was evident after an interval as short as 6 hr. In fact, the data suggest that virus was actually inactivated. In spite of this marked efficiency, morphologic alterations in spleens of adoptively immunized mice were absent. Attempts to reveal expansion of immune cells in the recipients have failed, and the observation that adoptive transfer was as efficient in nude mice as in their furred counterparts makes it unlikely that the recipients' T lymphocytes participated to any extent. The low number of T lymphocytes causing reduction of virus, the short interval after which the effect became measurable, and the lack of histopathologic alterations has led to a working hypothesis in which it is assumed that immunologically activated T lymphocytes secrete lymphokines that directly interfere with virus replication in neighboring cells.
Mechanism of action of thymosin. I. Thymosin fraction 5 increases lymphokine production by mature murine T cells responding in a mixed lymphocyte reaction.
Authors: Zatz M M , Goldstein A L
Published: December 2022

The effect of thymosin on the murine thymocyte mixed lymphocyte response was studied. Thymosin fraction 5 (TF5) caused a two- to threefold enhancement of the proliferative response and production of IL 2 when murine thymocytes were cultured with alloantigenic stimulator cells. Production of a second lymphokine, CSF, was increased up to sevenfold. The target cell for thymosin was a mature T cell, because the PNA- subpopulation of thymocytes, as well as peripheral lymph node lymphocytes, responded to culture with TF5 and alloantigen by enhanced proliferation and lymphokine production. The active component of TF5 appears to be one or more as yet unidentified peptides, because neither of the well-characterized TF5 component peptides, alpha 1 or beta 4, were active. After incubation with TF5 in primary culture, cells remaining after 10 to 14 days were increased both in number and in secondary response to alloantigen, as measured by lymphokine production. These results suggest that TF5 contains one or more biologically active components which can modulate mature T cell activity and lymphokine production, and which provide the basis for understanding some of the previously reported diverse effects of thymosin.
Heterogeneity and specificity of human anti-insulin antibodies determined by isoelectric focusing.
Authors: Thomas J W , Virta V J , Nell L J
Published: December 2022

Anti-insulin antibodies are present in the majority of insulin treated diabetics, and in some cases these antibodies have been found to be highly specific for limited epitopes on the molecule. To determine how the human response differs from that seen in inbred animals, we have examined the heterogeneity and specificity of human anti-insulin antibodies by isoelectric focusing (IEF). In addition, we have used human insulin to examine the extent of autoreactivity in the serum of subjects treated with animal insulins. The majority of diabetic sera exhibited complex IEF spectra that were composed of discrete bands and unresolved smears. Autoradiography using 125I-beef, pork, and human insulin revealed some affinity differences; however, the predominant antibodies were capable of binding all insulins, including human. These specificity studies were extended by comparing competitive inhibition with excess cold insulins, and sera with highly specific binding of the A chain loop of beef insulin were identified. The spectra by IEF of these highly specific sera were found to be variable. Our results indicate that the majority of insulin-treated diabetics develop a heterogeneous antibody response that is more complex than the response of inbred animals and includes reactivity with autologous insulin. Although infrequent, individuals having antibodies directed at limited regions of the molecule can be identified and will provide valuable tools for dissecting this complex response.
Shared idiotypy between phosphorylcholine-specific antibody and acetylcholinesterase detectable by a monoclonal antibody.
Authors: Strickland F M , Hamilton S L , Blalock E , Cerny J
Published: December 2022

Studies were undertaken to detect structural similarities between immunoglobulins and other proteins that bind to choline-containing ligands. Such proteins may share serologically detectable determinants that may not be predicted from the amino acid sequence alone. A monoclonal antibody was used that recognizes an idiotope near the phosphorylcholine binding site of the IgA myeloma TEPC15. This monoclonal anti-TEPC15 idiotopic antibody (anti-Id) also bound the enzyme acetylcholinesterase (AChE) as well as the nicotinic acetylcholine receptor from Torpedo californica. The anti-Id antibody also significantly decreased the AChE catalytic activity but did not affect the activity of an unrelated enzyme, horseradish peroxidase. These findings suggest that nonimmunoglobulin molecules share antigenic determinants with immunoglobulin that are associated with binding to structurally related ligands, and immune regulation may inadvertently affect the function of nonimmune systems.
Recognition and display of the predominant idiotype among members of the regulatory circuitry controlling the anti-lysozyme immune response.
Authors: Araneo B A , Yowell R L , Sercarz E E
Published: December 2022

The in vitro suppression of lysozyme (HEL)-primed helper T cell function (AgTh) is dependent on both suppressor inducer T cells (Tsi) (bearing the Lyt-1 and I-J surface antigens) and suppressor effector T cells (Tse) (bearing the Lyt-2 and I-A cell surface antigens). The AgTh and Tsi appear in draining lymph nodes of antigen-primed mice within 10 days of footpad immunization, whereas the Tse is detected in the lymph node around 21 days. Tse are localized to the spleen after i.p. immunization and represent the predominant functional T cell subset. In an attempt to understand the idiotypic relationships that exist among the three T cell types associated with anti-HEL responses in genetic low responder mice, each subset was characterized for expression of the predominant idiotype of anti-lysozyme antibodies, IdXL, by treatment with a cytotoxic anti-IdXL antibody and for IdXL-specificity by binding to IdXL-coated plates. Only the Tse was found to bear IdXL. The Tsi, on the other hand, binds to IdXL, and the AgTh belongs to a distinct idiotypic universe. These results suggest that the mode of communication between the Tsi and Tse is via idiotypic complementarity.
Localization of the conglutinin binding site on the third component of human complement.
Authors: Hirani S , Lambris J D , Müller-Eberhard H J
Published: December 2022

The binding site on the human third complement component for bovine conglutinin has been located. C3 fragments were purified to homogeneity by preparative SDS-polyacrylamide-gel electrophoresis. Only the N-terminal 27,000 dalton (Da) fragment of the alpha'-chain and the beta-chain were found to be glycosylated, and the carbohydrate was susceptible to endo-beta-N-acetylglucosaminidase H. This finding indicates that only high mannose or hybrid-type oligosaccharide chains are present on the C3 molecule. Binding to conglutinin was determined by an enzyme-linked immunosorbent assay and occurred with C3b, iC3b, C3c, the alpha-chain, and the 27,000 Da fragment of the alpha'-chain, but not with C3d or the C-terminal 40,000 Da fragment of the alpha'-chain. The beta-chain displayed very weak interaction. Binding to conglutinin could be inhibited by EDTA, N-acetylglucosamine, and to a lesser degree by mannose. Enzymatic removal of the carbohydrate from the C3 molecule abolished binding to conglutinin. It is concluded that bovine conglutinin binds to the carbohydrate moiety located on the N-terminal 27,000 Da polypeptide of the alpha-chain.
Inhibition of cytotoxic T lymphocyte-mediated lysis by ETYA: effect independent of arachidonic acid metabolism.
Authors: Taylor A S , Howe R C , Morrison A R , Sprecher H , Russell J H
Published: December 2022

Cytotoxic T lymphocyte (CTL)-mediated lysis of target cells was inhibited by 5,8,11,14-eicosatetraynoic acid (ETYA) and other inhibitors of the lipoxygenase pathway at concentrations that inhibited arachidonic acid metabolism in mixed lymphocyte cultures. Inhibition was reversible and selective for the "lethal hit" stage in the CTL-target interaction. Studies to define CTL-specific arachidonic acid metabolites demonstrated that cloned CTL populations have little or no capacity to metabolize arachidonic acid. Therefore, inhibitor actions appear to be independent of the effects on CTL arachidonic acid metabolism. Alternative explanations for inhibitory effects are discussed.
Immunoradiometric assay to measure the in vitro penetration of sporozoites of malaria parasites into hepatoma cells.
Authors: Zavala F , Hollingdale M R , Schwartz A L , Nussenzweig R S , Nussenzweig V
Published: December 2022

We describe here an immunoradiometric assay to quantitate the in vitro invasion of hepatoma cells by sporozoites. The assay measures levels of circumsporozoite (CS) antigen that remain associated with the hepatoma cells after their incubation with the parasites. Several observations show that these measurements reflect internalized rather than extracellular antigen. For example, when incubations were performed with nonviable parasites (sonicated or heated), or in the presence of metabolic inhibitors, such as sodium azide and deoxyglucose, the amounts of CS antigen found in hepatoma cell extracts were greatly diminished. Moreover, Western blotting experiments revealed a striking difference in the pattern of CS proteins of infected cell extracts as compared with those of free parasites. The assay was used to measure the amounts of intracellular CS antigen for several days after infection of the hepatoma cells. The results confirmed previous microscopic observations, made by using immunofluorescence techniques, showing that the CS antigen in the host's liver cells diminishes progressively while the parasite develops into the exoerythrocytic stage. The immunoradiometric assay should facilitate the evaluation of the effects of drugs on sporozoites and also on studies aimed at the identification of a sporozoite receptor on the hepatocyte.
Dissociation between aggregation and superoxide production in human granulocytes.
Authors: Whitin J C , Cohen H J
Published: December 2022

Aggregation and the activation of the granulocyte (PMN) superoxide (O2-) generating system occur when certain stimuli are added to resting cells. It had previously been postulated that PMN aggregation is essential for maximal O2- production. This study was undertaken to test the hypothesis that PMN aggregation is required for full expression of PMN O2- production. We examined aggregation and O2- production induced by four stimuli; concanavalin A (Con A), phorbol myristate acetate (PMA), N-formylmethionyl-leucyl-phenylalanine (FMLP), and ionophore A23187. Cytochalasin B enhanced aggregation by all four stimuli but only enhanced the rate of O2- production by Con A; 2-deoxyglucose inhibited aggregation by all stimuli. Dissociation of PMN aggregation and O2- production was achieved by using NEM, TPCK, and divalent cations. NEM and TPCK prevent Con A-induced O2- production but have no effect on Con A-induced aggregation. PMA-stimulated PMN generate O2- in the presence or absence of Ca++ and Mg++. In contrast, PMA stimulated maximum PMN aggregation only in the presence of both Ca++ and Mg++. Thus PMN can generate O2- without aggregating, and PMN can aggregate without producing O2-. PMN from patients with chronic granulomatous disease do not generate O2- or undergo membrane potential depolarization in response to PMA. These PMN aggregated when stimulated with PMA, providing evidence that depolarization is not required for PMN aggregation. We conclude that aggregation and the activation of the O2- generating system, though temporally related, are not necessarily causally related.
A role for mast cells and the vasoactive amine serotonin in T cell-dependent immunity to tumors.
Authors: Van Loveren H , Den Otter W , Meade R , Terheggen P M , Askenase P W
Published: December 2022

The involvement of mast cells in anti-tumor resistance was studied by employing 2 strains of mast cell deficient but otherwise immunocompetent mice on a C57BL/6 (H-2b) background (W/Wv and Sl/Sld) and their respective normal +/+ littermate controls. Sensitization of control mice with irradiated semisyngeneic B16 melanoma cells (H-2b) resulted in protection against subsequent challenge with viable B16 cells, in contrast to sensitization of either W/Wv or Sl/Sld mice. The involvement of serotonin in antitumor resistance was studied by employing 2 serotonin active drugs: reserpine, that depletes mast cells of serotonin; and methysergide, a serotonin antagonist. Sensitization of BDF1 mice with irradiated B16 cells and sensitization of DBA/2 mice (H-2d) with irradiated SL2 cells (H-2d) resulted in protection against subsequent challenge with viable B16 cells and viable SL2 cells, respectively. Treatment with either reserpine or methysergide resulted in a decreased protection. Delayed-type hypersensitivity (DTH) footpad responses to allogeneic L5178Y (H-2d) tumor cells in C57BL/6 mice showed a biphasic reaction pattern, similar to that found in DTH responses to simple reactive haptens, such as picryl chloride. Moreover, the early swelling responses were also dependent on T cells and on mast cells. BDF1 mice carrying a semisyngeneic L5178Y tumor on the chest showed an early swelling response after footpad challenge but no late response, possibly indicating that selective down regulation of the late component of DTH was associated with progressive tumor growth in these animals. The biphasic patterns of DTH to both tumor cells and picryl chloride and the T cell and mast cell dependence of both antitumor resistance and DTH to tumor cells suggest that T cell-dependent activation of mast cells to allow entry of mononuclear leukocytes into sites of tumor growth is similar to the mechanism that occurs in DTH.
Enhancement of tumor growth correlates with suppression of the tumor-specific cytolytic T lymphocyte response in mice chronically infected by Trypanosoma cruzi.
Authors: Plata F
Published: December 2022

The immunity of BALB.B mice to syngeneic Gross murine leukemia virus (MuLV)-induced B.GV cells was studied at various times after infection by Trypanosoma cruzi. BALB.B mice chronically infected by the parasite do not develop an effective immune response against B.GV tumor cells, and B.GV tumor growth in vivo is consequently facilitated. The tumor-specific cytolytic T lymphocyte (CTL) compartment in these mice was studied in vitro because CTL are known to participate actively in syngeneic tumor rejection. These analyses showed that: a) CTL differentiation is suppressed in mice with chronic T. cruzi infections; b) suppression is at the level of CTL precursor cell activation; c) suppression is not antigen-specific; and d) suppression is mediated by macrophages and Lyt-2+ T lymphocytes.
Cell-mediated T lymphocyte responses against syngeneic cells modified with amino-reactive hapten (AED-NH2): H-2Dk serves as an element for cell-mediated lympholysis to amino-reactive hapten (AED-NH2)-modified self.
Authors: Mizuochi T , Fujiwara H , Takai Y , Hamaoka T
Published: December 2022

Spleen cells from C3H/He mice immunized to the newly synthesized amino-reactive hapten, 5-sulfo-1-naphthoxy acetic acid N-hydroxysuccinimide (AED-NH2), were stimulated in vitro with AED-NH2 modified syngeneic cells. After 5 days of culture, effector cells were assayed for their cytotoxic activity against AED-NH2-modified target blast cells. In contrast to other amino-reactive haptens reported so far, a strong cytotoxic activity against AED-NH2-modified syngeneic cells was found in H-2b mice as well as in H-2k mice. Furthermore, Dk-restricted anti-AED-NH2 CTL recognition was observed in H-2k mice as shown by cold target inhibition. Previous studies have demonstrated the predominant influence of K over D region self determinants, and of the chemical reactivity of the haptenic reagent in Ir gene control of CTL response to hapten-self. The present report illustrates the importance of the hapten itself in genetic regulation of these CTL responses.
Molecular localization of allogeneic and self determinants recognized by bulk and clonal populations of cytotoxic T cells.
Authors: Levy R B , Ozato K , Richardson J C , Bluestone J A
Published: December 2022

The localization of MHC-encoded determinants recognized by hapten- and allo-specific cytotoxic T cells was analyzed with the use of cell lines expressing recombinant H-2Dd and H-2Ld MHC products. Bulk cultures of CTL against TNP-self, FITC-self, and AED-self recognized self determinants associated with the N/C1 domains of both Dd and Ld products. A number of allo- and hapten-specific CTL clones were also tested for recognition of the recombinant MHC products. The allo clones specific for Ld or Dd antigens recognized the respective N/C1-associated determinants. In addition, all clones generated against H-2q and known to cross-react with H-2Dd antigens recognized determinants associated with the N/C1-associated Dd determinants. Thus, some of the results obtained with CTL parallel, whereas others contrast with, those findings obtained with monoclonal anti-H-2 antibodies. Similar to the observations made with the monoclonal antibodies, no determinant as defined by T cells has been found to be lost as a result of the interaction between the N/C1 and C2/M domains of the Ld and Dd proteins. Nor did our studies detect the presence of new antigens resulting from the interaction of these gene products. However, the present T cell findings continue to contrast previous results demonstrating that antibody interaction with class I products includes recognition of C2/M-associated epitopes.
Common precursor pool marker for allospecific (CTL) and nonspecific (NK and activated) cytotoxic cells in the bone marrow.
Authors: Nieminen P , Saksela E
Published: December 2022

A recently described monoclonal mouse IgG1 antibody, NK-9, reacts with practically all peripheral blood large granular lymphocytes (LGL). It also detects a population of non-LGL lymphoid cells that harbors precursor cells for both nonspecific activated killer (AK) and allospecific killer cells. In the bone marrow, the NK-9-positive population represented 9% of all nucleated cells, which was 40% of all lymphoid cells. This population was initially noncytotoxic, but when appropriately stimulated the NK-9-positive cells gave rise to AK and allospecific cytotoxic cells, whereas no such activity could be generated from the NK-9-negative cells. When the NK-9-positive cells were cultured with high concentrations of T cell growth factor, the results were cultures consisting of over 80% cells with LGL morphology and exhibiting effective cytotoxicity against K562 targets. It is concluded that the precursor cells for various modes of nonspecific and antigen-specific cytotoxicity are related and appear to be harbored in the NK-9-positive pool in the bone marrow.
Influence of genotypes at a non-MHC B lymphocyte alloantigen locus (Bu-1) on expression of Ia (B-L) antigen on chicken bursal lymphocytes.
Authors: Fredericksen T L , Gilmour D G
Published: December 2022

Two inbred lines of chickens known to be identical at the MHC differ in their expression of Ia antigen on cells of the bursa. Line 6 bursas had 23% of intensely staining Ia+ cells while line 7 bursas had a much higher level, 85%. Studies of F4 progeny of line 6(3) X 100 crosses showed that genetic control of the high bursal proportion of Ia+ cells was determined by the Bu-1 alloantigen system. Line 100 is identical to line 7 for the lymphocyte alloantigens identified by the T and B cell reagents used in this study. Tests of F4 heterozygotes at the Bu-1 locus show a dominant effect of the Bu-1b gene in control of a high proportion of strongly staining Ia+ cells in the bursa.
Selective effect of irradiation on responses to thymus-independent antigen.
Authors: Lee S K , Woodland R T
Published: December 2022

Low doses of ionizing radiation have a selective immunosuppressive effect on in vivo B cell responses to thymus-independent (TI) antigens. The B cell response, assayed as direct anti-trinitrophenyl (TNP)-specific plaque-forming cells (PFC), induced by type 2, TI antigens (TNP-Ficoll or TNP-Dextran), was reduced, on the average, by 10-fold in animals exposed to 200 rad of ionizing radiation 24 hr before antigen challenge. In contrast, PFC responses to type 1, TI antigens (TNP-lipopolysaccharide or TNP-Brucella abortus) are unaffected in mice exposed to the same dose of radiation. Adoptive transfers showed that this selective immunosuppression is a result of the specific inactivation of the B cell subpopulation responding to type 2, TI antigens. These experiments suggest that physiologic differences exist in the B cell subpopulations of normal mice which respond to type 1, or type 2, TI antigens.
Further characterization of low density mononuclear cells: FACS-assisted analysis of human MLR stimulators.
Authors: Santiago-Schwarz F , Bakke A C , Woodward J G , O'Brien R L , Horwitz D A
Published: December 2022

Previously, we reported that all of the potent stimulators of the allogeneic mixed leukocyte reaction (MLR) are contained in a heterogeneous low density fraction of human peripheral blood mononuclear (PBM) cells. We have further characterized human MLR stimulators by staining them with highly specific monoclonal antibodies, and then analyzing and separating them with the fluorescence-activated cell sorter. These studies revealed two populations of low density cells with potent allogeneic stimulatory activity. One population is a monocyte subset that reacts with anti-OKM1, MO.2, and expresses C3b as well as Fc-IgG receptors. The second population exhibits even greater stimulatory capacity and does not express any of these monocyte markers. Moreover, these cells are not phagocytic and do not react with alpha-naphthyl esterase. They comprise approximately 10% of the low density fraction or 0.5% of PBM. These cells are most likely lymphoid dendritic cells, described in various species as potent MLR stimulators. In contrast to the allogeneic MLR, only the low density cell type exhibiting dendritic cell characteristics induced a potent autologous MLR.
Recombinant interleukin 2 enhanced natural killer cell-mediated cytotoxicity in human lymphocyte subpopulations expressing the Leu 7 and Leu 11 antigens.
Authors: Lanier L L , Benike C J , Phillips J H , Engleman E G
Published: December 2022

Highly purified recombinant human interleukin 2 (rIL 2) markedly augments the natural killer (NK) cell-mediated cytotoxicity of peripheral blood lymphocytes. In this study, we examined the cellular and metabolic basis of rIL 2-mediated activation of human lymphocyte subpopulations expressing the NK cell-associated surface antigens Leu 7 and Leu 11. All rIL 2-responsive cytotoxic NK cells were found within the subset of lymphocytes expressing the Leu 11 marker, an antigen associated with the Fc-IgG receptor on human NK cells. Cells lacking the Leu 11 antigen, including cells expressing another NK cell-associated marker, Leu 7, did not express NK cell-mediated cytotoxicity either before or after rIL 2 treatment. By contrast, rIL 2 augmented the NK activity of both Leu7-,11+ and Leu 7+,11+ subpopulations. Activation of Leu 11+ NK cells resulted from a direct effect of rIL 2 on these cells and neither required nor was amplified by the presence of T lymphocytes. Enhanced NK cell-mediated cytotoxicity occurred within 4 hr after exposure to rIL 2, and was blocked by the protein synthesis inhibitor cyclohexamide, but not by the DNA synthesis inhibitor mitomycin C or 1500 rad of x-irradiation. Neither Tac antigen, a high-affinity receptor for IL 2, nor other activation markers, such as transferrin receptor or HLA-DR antigen, were detectable on a significant proportion of Leu 11+ cells, either before or after incubation with rIL 2 for 48 hr. In addition, saturating concentrations of antibodies to each of these markers had no effect on the enhancement of NK activity by rIL 2. Finally, preliminary experiments with neutralizing antibodies to gamma- and alpha-interferons also failed to prevent rIL 2 enhancement of NK cell-mediated cytotoxicity, suggesting that rIL 2 does not mediate its effect via release of these cytokines.
Synergistic effect of concanavalin A and Bu-WSA on DNA synthesis in human peripheral blood lymphocytes.
Authors: Nitta T , Okumura S , Nakano M
Published: December 2022

Butanol-extracted water soluble adjuvant (Bu-WSA) obtained from Bacterionema matruchotii was not mitogenic for human peripheral blood mononuclear cells (PBM) but was capable of enhancing (3H) thymidine uptake of T cells stimulated by concanavalin A (Con A) in the presence of B cells or macrophages (M phi) in vitro. The mechanisms of the synergy of Con A and Bu-WSA were studied by using separated cell populations from PBM. Both subfractioned OKT4+ and OKT8+ cells were responsive to co-stimulation by Con A and Bu-WSA in the presence of an accessory cell population. Allogeneic B cells and M phi as well as autologous cells had helper function as accessory cells. Heavy irradiation with gamma-rays did not affect the function of the accessory cells, but previous treatment of B cells with anti-Ig serum plus complement (C) or treatment of M phi with anti-M phi serum plus C deprived them of their function. The treatment of accessory cells with anti-HLA-DR serum, regardless of the presence or absence of C, resulted in loss of their helper function. Cultures in Marbrook-type vessels showed that a mixed cell population of T cells and accessory cells in the lower chamber produced some active factor(s) after co-stimulation with Con A and Bu-WSA, and by passing through the membrane filter separating the chambers, the factor(s) enhanced the proliferation of the Con A-activated T cell population in the upper chamber. The factor(s) was presumed to be interleukin 2 (IL 2), because it supported the growth of IL 2-dependent CTLL cells. These results indicate that the synergy of Con A and Bu-WSA on the proliferative response of human PBM is due to the elevation of growth factor production from T cells stimulated by those mitogens.
Separation of a population of human T lymphocytes that bind prostaglandin E2 and exert a suppressor activity.
Authors: Fischer A , Le Deist F , Durandy A , Griscelli C
Published: December 2022

Prostaglandin E2 (PGE2) is a potent inhibitor of immune functions. Two possible mechanisms of PGE2-mediated suppression have been proposed: one is a direct inhibitory effect exerted on interleukin 2-producing T cells; the second is mediated by the activation of nonspecific suppressor T lymphocytes. We previously showed that PGE2 can directly activate human T lymphocytes to suppress lymphocyte proliferation and B lymphocyte maturation. Herein is described the binding of 10 to 30% of human peripheral blood T lymphocytes to insolubilized PGE2 coated to albumin-Sepharose. The T lymphocytes that bound PGE2 (PGE2(+] could be eluted by the addition of serum and gentle shaking of the beads. The following data indicated the specificity of the binding: i) T lymphocytes after an overnight incubation, a condition known to abolish sensitivity to PGE2, lost their affinity for PGE2; ii) preincubation of T lymphocytes with PGE2 blocked the binding; iii) PGE2(+) T cells bound PGE after a 24-hr incubation, whereas PGE2(-) T cells did not. Few T cells bound albumin, and only a small percentage (7 to 9%) bound 6-keto-prostaglandin F1 alpha-coated beads. Among PGE2(+) T cells, there was a slight increase in the percentage of OKT8+ cells. Although T cells that had no affinity for PGE2 (PGE2(-] proliferated as well as unseparated T lymphocytes when stimulated with mitogens or antigens, the proliferative response of the PGE2(+) subset was poor. Moreover, PGE2(+) T lymphocytes did exert a strong suppressor activity on mitogen- or allogeneic cell-induced lymphocyte proliferation as well as on pokeweed mitogen-driven B cell maturation into Ig-containing cells. PGE2(-) T lymphocytes were shown not to exert a significant suppressor activity in these assays. The PGE2(+) subset-mediated suppression was not secondary to a carry-over of PGE2 released from the beads, because its suppressor activity was not altered by the addition of an anti-PGE2 serum. Moreover, PGE2(-) T lymphocytes were not sensitive to the inhibitory activity on cell proliferation of PGE2. These results indicate that a given functional subset of peripheral blood T lymphocytes binds PGE2, and that at least some of them are activated into suppressor T cells. The relationship between the PGE2-activatable T suppressor subset and other functionally defined suppressor T cells remains to be clarified; it is suggested, however, that PGE2 can act as an immunoregulator through the activation of identifiable suppressor T cells.
Isolation and functional analysis of human B cell populations. I. Characterization of the B1+B2+ and B1+B2- subsets.
Authors: Anderson K C , Boyd A W , Fisher D C , Slaughenhoupt B , Groopman J E , O'Hara C J , Daley J F , Schlossman S F , Nadler L M
Published: December 2022

Distinct populations of human B lymphocytes can be identified by their expression and/or co-expression of the B cell-restricted antigens B1 and B2. Dual fluorochrome staining and flow cytometric cell sorting permitted the isolation of the B1+B2+ and B1+B2- cells to homogeneity. In contrast, very few B1-B2+ cells were obtainable from normal lymphoid organs. Virtually all B1+B2+ cells expressed IgM and IgD, but lacked IgG and the plasma cell antigens PCA-1 and PC-1, whereas the B1+B2- cells more frequently expressed IgG, PCA-1 and PC-1. Both populations were noncycling and were composed of similar percentages of small and large cells. The B1+B2+ cells proliferate to anti-mu or to anti-mu + PHA-LCM, but not to PHA-LCM alone. They require both T cells and PWM to produce Ig. In contrast, B1+B2-cells do not significantly proliferate to anti-mu, PHA-LCM, or anti-mu and PHA-LCM. They produce Ig in response to T cells alone without PWM. These phenotypic and functional observations provide preliminary evidence that these populations are distinct and that the B1+B2+ cell may be a "resting" B cell, whereas the B1+B2- cell appears to be more "differentiated." The present studies further suggest that they will also be helpful in characterizing B cells in some human disease states. We believe that the identification and isolation of these and similar subsets of B cells defined by differing cell surface phenotype should aid our understanding both of normal B cell differentiation and of B cell disease states.
Comparison of response to stem cell differentiation signals between normal and autoimmune mouse strains.
Authors: Raveche E S , Chused T M , Steinberg A D , Laskin C A , Edison L J , Tjio J H
Published: December 2022

Normal DBA/2 and autoimmune NZB mice were studied with regard to signals eliciting differentiation and division of bone marrow stem cells. Irradiated (NZB X DBA/2)F1 mice were repopulated with various combinations of T-depleted bone marrow from NZB and DBA/2 mice. In response to the repopulation signal of irradiation, recipients of autoimmune NZB marrow initially demonstrated expansion of LY-5+ lymphoid and hemopoietic cells, particularly of the B cell lineage. The greater the proportion of NZB marrow, the higher the percentage of lymphoid cells observed 2 wk post-repopulation. B cells (ThB-positive cells) were increased in disproportionate numbers in recipients of NZB marrow, even those that had received as little as 20% NZB bone marrow cells. However, by 2 mo, the initially observed increase in lymphoid cells in recipients of NZB marrow was no longer observed. Up to 6 mo post-repopulation, cytogenetic analysis revealed that irradiated recipients were repopulated in the same proportion of DBA/2: NZB as was in the injected marrow. Endogenous colony formation assays indicated that recipients of 100% NZB, 80% NZB, and 20% NZB marrow all had greater numbers of splenic endogenous colonies than did recipients of DBA/2 marrow alone. These studies indicated that autoimmune NZB marrow repopulated irradiated mice in the proportion in which it was injected, but there was a disproportionate early increase in cells of the B lineage as well as a disproportionate increase in splenic colony formation.