Regulation of bone marrow lymphocyte production: IV. Cells mediating the stimulation of marrow lymphocyte production by sheep red blood cells: Studies in anti-IgM-suppressed mice,athymic mice,and silica-treated mice

Some cellular requirements have been examined for the stimulation of lymphocyte production in mouse bone marrow by injected sheep red blood cells (SRBC). The increased genesis of marrow lymphocytes after a single dose of SRBC assayed radioautographically after [³H]thymidine labeling was unimpaired in the marrow of mice treated with anti-IgM antibodies from birth to eliminate B lymphocytes, and in congenitally athymic mice lacking T lymphocytes. However, pretreatment of mice with silica to depress macrophage function completely abolished the SRBC effect both on the total lymphocyte production and on the number of B and null small lymphocytes in the marrow. Comparative studies were performed on the thymus and spleen. The results demonstrate that the stimulation of marrow lymphocyte production by SRBC is mediated by a silica-sensitive mechanism, does not require B or T lymphocytes, and is independent of the humoral immune response. Thus, extrinsic agents may amplify the production of primary B cells and other lymphocytes in the bone marrow by an antigen-nonspecific mechanism, putatively mediated by macrophages.     

Induction of delayed-type hypersensitivity to measles virus in mice

Intracutaneous injection of inactivated measles virus (MV) into hind footpads of BALB/c mice infected 5 to 11 days previously with MV produces a strong delayed-type hypersensitivity (DTH) response. Pretreatment of mice with cyclophosphamide (CP) results in a significantly stronger response. In CP-pretreated mice, the optimal infecting dose of live MV and the restimulating amount of inactivated MV are approximately 10(7) plaque-forming units and 2 micrograms/mouse, respectively. The optimal time after infection for measuring DTH to MV is 7 days, while the optimal CP-pretreatment concentration is 200 mg/kg. The DTH response generated by MV is specific and not caused by fetal calf serum or Vero cell antigens. MV DTH is transferable to uninfected mice with lymph node cells. Transfer of DTH is sensitive to treatment with anti-Thy 1.2 serum plus complement, indicating the response is T cell dependent. With this sensitive assay for measuring cell-mediated immunity to MV, it will now be possible to analyze T cell cross-reactivity among paramyxoviruses and assess viral cell-mediated immunity in mice infected with neuroadapted MV.     

Macrophage-like suppressor cells in rats. I. Inhibition of natural macrophage-like suppressor cells by red blood cells

When trinitrobenzenesulfonic acid (TNBS), the reactive form of trinitrophenyl (TNP) hapten, is injected into a mouse, a brief intrinsic B-cell tolerance to TNP has been shown to result. Yet antigen-binding cells (ABC) with receptors for TNP persist in the TNBS-treated animal.After treatment with Pronase under conditions preserving cell recovery and viability, 80–90% of TNP-ABC failed to bind antigen. After 2 hr in vitro, Pronase-treated 4-day immune TNP-ABC displayed significant recovery of antigen binding, whereas nonimmune TNP-ABC performed the same feat by 18 hr. However, TNP-ABC tested 2 to 11 days after TNBS failed to replace digested receptors by 18 hr in vitro. Thirty days after TNBS, they had recovered this ability. This defective receptor replacement by TNP-ABC was not reversed by colchicine, and was not shared by the sheep-erythrocyte ABC of the same animals, which replaced receptors normally. When challenged with antigen (TNP-sheep erythrocytes) simultaneously with TNBS, recovery by 2 hr was evident on Day 11. When challenged with antigen 4 days after TNBS, receptor regeneration had returned to normal by the next day, and partial recovery of the anti-TNP plaque-forming cell response was evident 4 days later.Thus, the inability to replace receptors and immune unresponsiveness coincides in time, so that a causal relationship between these two defects may be hypothesized. This result contrasts with the membrane locking defect, previously described in the TNP-ABC of TNBS-treated animals, which far outlasted the unresponsive state.     

Determination of butaperazine in plasma and red blood cells by fluorometry

A simple and sensitive fluorometric method is described for the determination of butaperazine in plasma and red blood cells. This method is specific for butaperazine and reproducible over a wide range of drug levels in the blood. The sensitivity of the method is 8 ng/ml of blood, but could be increased for determining much lower levels.     

Immunity to carcinogen-induced transplantable fibrosarcoma in B2B2 chickens: V. Relationship to tumor cell-specific delayed hypersensitivity and serum antibody

Lasting immunity to the chemically induced (DMBA) fibrosarcomas (CHCT-NYU1, 2, and 4) of SC chickens ($\text{B2}\text{B2}$) can be obtained by injection of Corynebacterium parvum (CP)-primed chickens with tumor cells and CP in one wing and tumor cells alone in the other wing. The local delayed hypersensitivity (DH) reaction to CP in the wing inhibits local growth completely, whereas the tumor on the contralateral side shows transient growth. In the present studies, the development of tumor immunity was studied in detail by monitoring DH and antibody formation to the tumor cells and adoptive immunity with spleen cells in Winn tests. Injection of NYU1 cells alone in normal or CP-treated animals induced transient immunity in Winn tests in 50% of the animals, weak DH reactivity, and antibody detectable by immunofluorescence within the first 2 weeks. Chickens receiving both NYU1 cells and CP in one wing and NYU1 cells alone on the other side developed stronger DH reactions to the tumor cells and a higher incidence of immunity in Winn tests which was sustained throughout the period of observation. Antibody levels were similar to those of animals receiving tumor cells alone. In contrast, injection of CP and tumor cells on one side without a tumor challenge on the contralateral side did not induce detectable immunity in CP-primed chickens. Chickens immunized to NYU2 and 4 cells were also tested for DH reactivity and antibody formation. Studies on the cross-reactivity between the tumor lines showed that there was cross-reactivity at the humoral level while at the cellular level this was not apparent. However, animals immune to one tumor line rejected transplants of another tumor line. Observations on the antibody specificity(s) suggested that it was not directed against minor histocompatibility or avian sarcoma viral antigens. SC embryo fibroblasts could induce DH, and serum antibody induced by tumor cells usually reacted also with such embryo cells.     

Pig red blood cell hexokinase: Regulatory characteristics and possible physiological role

The regulatory properties of pig erythrocyte hexokinase III have been studied. Among mammalian erythrocyte hexokinases, the pig enzyme shows the highest affinity for glucose and a positive cooperative effect with n_H = 1.5 at all the MgATP concentrations studied (for 0.5 to 5 mm). Glucose at high concentrations is also an inhibitor of hexokinase III. Similarly, the apparent affinity constant for MgATP is independent of glucose concentration. Uncomplexed ATP and Mg are both competitive inhibitors with respect to MgATP. Glucose 6-phosphate, known as a stronger inhibitor of all mammalian erythrocyte hexokinases, is a poor inhibitor for the pig enzyme (K_i = 120 μm). Furthermore, this inhibition is not relieved by orthophosphate as with other mammalian red blood cell hexokinases. A variety of red blood cell-phosphorylated compounds were tested and found to be inhibitors of pig hexokinase III. Of these, glucose 1,6-diphosphate and 2,3-diphosphoglycerate displayed inhibition constants in the range of their intracellular concentrations. In an attempt to investigate the role of hexokinase type III in pig erythrocytes some metabolic properties of this cell have been studied. The adult pig erythrocyte is able to utilize 0.27 μmol of glucose/h/ml red blood cells (RBC) compared with values of 0.56–2.85 μmol/h/ml RBC for the other mammalian species. This reduced capacity to metabolize glucose results from a relatively poor ability of the cell membrane to transport glucose. In fact, all the glycolytic enzymes were present and a low intracellular glucose concentration was measured (0.5 mm against a plasma level of 5 mm). Furthermore, transport and utilization were concentration-dependent processes. Inosine, proposed as the major energy substrate of the pig erythrocyte, at physiological concentrations is not as efficient as glucose in maintaining reduced glutathione levels under oxidative stress. Furthermore, newborn pig erythrocytes (fully permeable to glucose) possess hexokinase type II as the predominant glucose-phosphorylating activity. This fact and the information derived from the study of the regulatory characteristics of hexokinase III and from metabolic studies on intact pig erythrocytes permit the hypothesis that the presence of this peculiar hexokinase isozyme (type III) enables the adult pig erythrocyte to metabolize low but appreciable amounts of glucose.     

Erasure of the memory response in MEL cells

When MEL cells are reexposed to DMSO after an interruption in inducer treatment, they can initiate commitment to differentiation without the lag period observed after the primary exposure to inducer. This property is known as memory. Here we have employed metabolic inhibitors to analyze the basis of the memory response. Treatment of cells with cycloheximide or cordycepin during the inducer withdrawal period causes memory erasure. Cells must recapitulate an entire lag period upon reexposure to DMSO. The memory response is maintained, however, if cells are treated with metabolic inhibitors in the presence of DMSO. Our results suggest that the capacity of MEL cells for memory requires the synthesis of cell components which are normally stable in the absence of DMSO. Experiments involving reciprocal shifts between two different inhibitors have been performed. Evidence is presented that the process leading to the initiation of commitment is composed of at least three components acting in sequence.     

Suppression of delayed-type hypersensitivity to third party "bystander" alloantigens by antigen-specific suppressor T cells

Delayed-type hypersensitivity (DTH) against alloantigens can be induced by sc immunization with allogeneic cells. The induction of DTH can be suppressed by iv preimmunization of the mice with similar allogeneic spleen cells, provided the cells are irradiated before injection. This suppression is mediated by T cells. The suppressor activity can be induced not only by H-2-and non-H-2-coded antigens, but also by H-2 subregion-coded antigens. Suppression induced by K, I, or D subregion-coded antigens is specific for that particular subregion as well as for its haplotype. I-J-coded alloantigens were found to not be necessary for the induction of antigen-specific suppressor T cells. After restimulation of suppressor T cells by the "specific" alloantigens, the DTH to simultaneously administered third-party alloantigens becomes suppressed as well. This nonspecific suppression of DTH to third party "bystander" alloantigens also occurs when the specific and the third-party antigens are presented on separate cells, provided that both cell types are administered together at the same site. The simultaneous presentation of both sets of alloantigens during the induction phase of DTH only is sufficient to prevent the normal development of DTH to the third-party antigens.     

Suppressor T cells in thymus-reconstituted nude mice: regulation of mitogen-induced transformation

A population of glass-wool-adherent splenic cells which could suppress the response of other spleen cell populations to T-cell mitogens was isolated from thymus-reconstituted nude mice. Such adherent cells were characterized as sensitive to anti-Thy 1.2 and complement treatment. Glass-wool-adherent cells from athymic mice do not have suppressor activity to self or normal littermate NAC; however, these mice possess precursor suppressor cells as demonstrated by isolation of glass-wool-adherent T regulatory cells in thymus-grafted nude mice. Such cells are generated in either freshly obtained or in vitro cultured thymus. Evidence for suppressor T cells of host genotype was supported by their sensitivity to host-specific anti-Thy serum treatment as well as their generation in alymphoid thymus grafts. Prior anti-Thy 1.2 treatment of GAC partially removed the suppressor activity: however, macrophages and B lymphocytes were shown not to be secondary regulatory cells or suppressor mediators, thus mature T lymphocytes with low amounts of Thy 1.2 antigen may be responsible for this residual suppression. Further characterization of GAC indicates that active cell growth is required for their regulatory function, as irradiation removed the suppressor activity. This report provides evidence for the presence of a T-lymphocyte subpopulation which has a regulatory function and requires a thymus in the generation of these cells.     

The influence of artificial photoperiod on the growth,appetite and reproductive status of male red deer and sheep

Young male red deer and Suffolk X (Finn X Dorset) sheep were kept on an artificial photoperiod such that two cycles of daylength occurred during one calendar year. They were penned separately, fed to appetite, weighed weekly and measured tri-weekly.Both species showed two cycles of intake, growth and gonadal activity in response to the daylength when only one would have been shown on natural photoperiod, although in the sheep these cycles were of lower amplitude than in the deer. The deer grew two sets of antlers during the study. A lag of some 3–4 months occurred between an event such as peak food intake and the time it would have been expected to occur relative to the daylength cycle. It is considered that although daylength controls these cycles, there is an endogenous rhythm which photoperiod cannot completely suppress.     

Activation of T cells in tumor-bearing mice

Subcutaneous transplantation of the syngeneic P815 mastocytoma in DBA/2J mice induced an activation of splenic T cells which resulted in a hyperresponsiveness of the tumor-bearing animal to the unrelated antigens pneumococcal polysaccharide (Pn) and sheep red blood cells (SRBC). These tumor-activated T cells appeared to increase the plaque-forming cell (PFC) potential of suboptimal numbers of spleen cells, caused normal spleen cells to express increased numbers of PFC, and produced lymphokine(s) which also increased PFC responses of normal splenocytes. The tumor-activated T cells responsible for stimulating normal splenocytes in an in vitro antibody response were shown to be Ly+2- cells. The activity of the tumor-activated T-cell supernatants was not genetically restricted and required additional Ly1 T cells in order to induce rigorously clean B cells to produce antibody. The T cells capable of stimulating non-specific antibody responses were also capable of slowing tumor growth when injected with tumor cells in normal recipient mice. These results suggest that T cells activated by tumor antigens release immunostimulatory lymphokines and, at the same time, are capable of leading to inhibition of tumor growth.     

Effects of pertussis toxin on delayed-type hypersensitivity responses and on the activity of suppressor T cells on the responses

Experiments were performed on mice to investigate the effects of pertussis toxin (PT) on delayed-type hypersensitivity (DTH) to ovalbumin (OA) and on the activity of suppressor T cells on the DTH (DTH-Ts). Mice immunized with alum-precipitated ovalbumin showed a transient DTH, which was determined as footpad swelling which disappeared 2 weeks after immunization. Maximal footpad swelling was observed 24 hr after DTH elicitation. On the other hand, when mice received PT (2 micrograms/mouse) at the time of immunization, the transient DTH became an enhanced and persistent DTH, which persisted for at least 4 weeks. In addition, the time of maximum footpad swelling was delayed from 24 to 48 hr after DTH elicitation. The immune spleen T cells from PT-treated mice showed a persistently high ability to transfer DTH into syngenic naive mice. DTH-Ts was induced in spleens of mice injected iv with OA-coupled syngeneic spleen cells. However, when these mice received PT at the time of suppressor induction, their spleen cells revealed considerably reduced suppressor activity. The activity of DTH-Ts was also reduced when DTH-Ts were either treated in vitro with PT or transferred into PT-injected recipient mice. From these results, interference with the suppressor function of DTH-Ts from PT was considered to be, at least in part, as an enhancing mechanism of DTH.     

Regulatory mechanisms of cutaneous delayed-type hypersensitivity: I. Suppression of cutaneous delayed-type hypersensitivity by migration inhibitory factor

The macrophage migration inhibitory factor (MIF) fraction was prepared from the immunoadsorbent column by using anti-guinea pig MIF antiserum. Suppression of cutaneous delayedtype hypersensitivity was achieved by intraperitoneal injection of the MIF fraction into the animals bearing macrophage-rich peritoneal exudates. Skin reactions induced by phytohemagglutinin (PHA) were also suppressed in these animals. Reactivity to skin reactive factor (SRF) was suppressed in these animals as well. The sera obtained from these animals exhibited the inhibitory activity against production of lymphokines from sensitized lymphocytes.     

Very long-lived messenger RNA in ovaries of Xenopus laevis

It is possible to label with radioactivity newly synthesized ovarian RNA after intraperitoneal injection of [³H]guanosine and [³H]uridine into immature Xenopus laevis, if ovaries in which only previtellogenic stage 1 oocytes are present. Following the amount of radioactivity in the ovarian pool of acid-soluble precursors indicates a complete clearance of acid-soluble radioactivity within 15–20 days after injection. Incorporation of radioactivity into total RNA (which is almost exclusively 4 and 5S RNAs at this stage) and poly(A)⁺ RNA ceases between 15 and 20 days after injection, but the total amount of radioactivity in these RNA fractions does not decline appreciably over the next 18 months. During this time, the ovary grows and develops since stage 6 oocytes eventually appear and there is a 10- to 20-fold increase in total RNA content, which changes in composition from almost exclusively (95%) 4 and 5S RNAs to mainly (75%) 18 and 28S RNAs. Thus, despite continued growth and development, radioactive RNA molecules synthesized during previtellogenesis survive for lengths of time commensurate with the length of oogenesis (1–2 years). Although very limited (<7%) reincorporation of radioactivity into RNA is detected, it cannot alone account for the stability of the label in poly(A)⁺ RNA. These results are interpreted as indicative of synthesis during previtellogenesis of tRNA, 5SrRNA, and messenger RNA molecules which are very long-lived.     

Antigen-specific augmentation of delayed-type hypersensitivity by a humoral factor in the culture supernatant of immune spleen cells

Supernatants were harvested from a 24-hr culture of immune mouse spleen cells and erythrocyte antigens. Delayed footpad reactions to such heterologous erythrocytes were augmented antigen specifically when the supernatants were transferred a few hours before immunization of recipients. The augmentation factor(s) contained in the supernatants may exert its effect on the induction phase of delayed-type hypersensitivity.     

Analysis of early events occurring during neonatal induction of tolerance to histoincompatible cells in mice

Mice have been analyzed at different times post neonatal inoculation of F₁ hybrid lymphoid cells for their ability to respond to foreign MHC antigens expressed on the tolerizing cell population, and to impart that response phenotype to normal adult spleen cells. At early times following neonatal challenge with F₁ spleen cells all mice produced serum immunoglobulins of F₁ donor origin which inhibited the response of normal adult cells. The antigenic specificity of the inhibitory factors suggests a role for an antireceptor antibody in the inhibition seen, and the presence of such serum-mediated inhibition is indicative of (and may be causally related to) the late appearance of a cell-mediated suppressor mechanism in these mice.     

Complementation of the anti-TNP PFC response of N:NIH nude mice from nude dams by spleen cells of nude mice from heterozygous dams.

Type I and Type II nude (nu/nu) mice are borne and raised by nu/nu dams and +/nu dams, respectively, under SPF conditions. Splenocytes from Type I nude mice exhibit even smaller in vitro PFC responses to trinitrophenylated rabbit erythrocytes than splenocytes from Type II nude mice. Type II splenocytes complement the magnitude of the PFC response of Type I splenocytes. The helper cell-like activity contained in Type II splenocyte suspensions was increased by treating Type II nude donor mice with dibutyryl cyclic AMP, but was essentially unaffected by pretreatment of Type II donors with endotoxin (LPS). The helper-like activity of Type II splenocytes was suppressed by treatment with a rabbit antiserum (plus C′) raised against a mixture of neonatal mouse thymocytes (RAM-T). We interpret the data to indicate that Type II splenocytes contain a larger number of residual T cells and/or a more fully developed population of T precursor cells that initiate or that are capable of being induced to initiate a helper function.     

Regulatory mechanisms of cutaneous delayed-type hypersensitivity. II. Suppression of cutaneous delayed-type hypersensitivity by macrophage disappearance reaction

Studies were performed on the behavior of cutaneous delayed-type hypersensitivity (DTH) in guinea pigs in which macrophage disappearance reaction (MDR) was induced. Guinea pigs were immunized with dinitrophenylated egg albumin (DNP-EA), followed by intraperitoneal (ip) injection of liquid paraffin in order to elicit peritoneal macrophages. Subsequently 20 micrograms of EA was injected into these animals and the animals were divided into two groups. One group of animals was sacrificed for estimation of MDR 6 hr after the subsequent ip injection. The other group received a skin test by EA at the time of the subsequent ip injection. The first group of animals sacrificed for estimation of MDR exhibited a marked reduction in the number of peritoneal macrophages. The second group of animals that received skin tests revealed suppressed skin reactions 24 hr after the subsequent ip injection. A similar experiment was performed using the guinea pigs doubly immunized with DNP-EA and dinitrophenylated bovine gamma-globulin (DNP-BGG). Induction of MDR was performed by ip injection of BGG and skin tests were done by both EA and BGG. As a result, suppression of not only BGG-induced skin reactions but also EA-induced skin reactions was observed in animals in which MDR had been induced by BGG. In addition, the guinea pigs in which MDR was induced showed hyporeactivity to phytohemagglutinin (PHA). Reactivity to skin reactive factor (SRF) was also suppressed in these animals. The culture supernatants of macrophages incubated with the MIF fraction in vitro showed the ability to suppress skin reactions of cutaneous DTH, PHA and SRF.     

Changes in cell populations and immunoglobulin-producing cells in the spleens of mice infected with Trypanosoma cruzi: correlations with parasite-specific antibody response

Infection of mice with Trypanosoma cruzi elicits the production of parasite-specific antibodies which reach high levels and remain elevated for at least 105 days of infection. The more susceptible C3H(He) mouse actually has a higher level of "natural" antibodies for T. cruzi but may show a greater lag time in the production of antibodies in response to infection than the more resistant C57BL/6 mouse. Comparison of the kinetics of antibody production against T. cruzi and the numbers of immunoglobulin-producing cells in the spleen during the course of infection suggests that a large number of the immunoglobulin-producing cells are probably producing antibodies directed against the parasite and are not the result of an exhaustive polyclonal B-cell activation. Cell numbers in the spleen change dramatically both in total numbers and in the percentage of different cell types during infection with T. cruzi. The percentage of T cells in the spleen remains relatively unchanged throughout infection in both mouse strains tested but numbers of Ig-positive cells decrease markedly during the acute phase of infection while macrophage numbers increase up to sixfold. Cell numbers and proportions of B cells, T cells, and macrophages return to near normal values by 105 days of infection in the C57BL/6 mouse.