Induction Of Cell-mediated Immunity Research Articles

Vaccination against cutaneous leishmaniasis in a murine model. I. Induction of protective immunity with a soluble extract of promastigotes.

BALB/c mice can be protected against a fatal Leishmania major infection by immunization with whole radio-attenuated promastigotes; however, neither the antigens responsible for protection nor the protective immunologic mechanisms have been defined. In this study, the ability of promastigote fractions to elicit similar immunity to that obtained with whole organisms, and the immune responses associated with such protection were analyzed. Intraperitoneal immunization with a soluble, membrane-free parasite extract was found to induce protection against L. major challenge equal to that obtained with whole organisms. Induction of immunity (89% protection in seven experiments) was most effective with 100 micrograms of the soluble leishmanial antigen (SLA) and required concomitant injection of the bacterial adjuvant, Corynebacterium parvum (CP), followed by an i.p. boost of SLA alone 1 wk later. Vaccinated animals exhibited Leishmania-specific cell-mediated immunity, as assessed both by lymphocyte transformation and the production of macrophage-activating factors (MAF). In addition, although SLA + CP-immunized mice failed to exhibit delayed-type hypersensitivity (DTH) before challenge, splenic lymphocytes from these mice could transfer a local DTH reaction to naive recipients. Immunization also induced the production of antibodies against two major metabolically labeled proteins of m.w. 30,000 and 53,000, but failed to stimulate a detectable humoral response against promastigote surface antigens. Thus, these experiments demonstrate that vaccine-induced immunity against cutaneous leishmaniasis is strongly associated with the induction of cell-mediated immunity, but does not require the development of an antibody response to promastigote surface antigens. In addition, these studies establish the feasibility of employing soluble, nonmembrane-derived parasite material as a source of protective immunogens.

Prospects for a nonliving vaccine against schistosomiasis based on cell-mediated immune resistance mechanisms.

We have designed a vaccine model based on induction of cell-mediated immunity and shown that it protects mice against Schistosoma mansoni infection. Mice are immunized by intradermal injection with schistosome antigens plus BCG. Resistance is dependent on the route of antigen presentation and the adjuvant chosen. The pattern of resistance correlates with sensitization of T lymphocytes for production of gamma interferon, a macrophage activating lymphokine that stimulates the cellular effector mechanism of protection. Purified schistosome paramyosin, a muscle cell component present in soluble parasite antigenic preparations, is immunogenic for T lymphocytes and induces resistance when given intradermally with BCG. It is likely that this protein, and possibly other soluble molecules that are released by the parasites of a challenge infection, induce a cellular inflammatory response resulting in larval trapping and/or killing by activated macrophages. These results verify the feasibility of a vaccine against schistosomiasis based on induction of cell-mediated immune resistance mechanisms.

Experimental screening of BCG preparations produced for cancer immunotherapy: safety and immunostimulating and antitumor activity of four consecutively produced batches.

Four consecutively produced batches of Bacillus Calmette-Guérin (BCG) especially intended to be used for cancer immunotherapy were investigated for consistency of the vaccine. Each batch was investigated directly after production of the vaccine, so that the four batches were not tested simultaneously. The activity of the four batches was investigated in general safety assays, immunostimulation assays, and two different tumor models. General safety assays showed dose-dependent growth retardation and increased serum glutamic pyruvic transaminase activity in mice, and a long-lasting temperature rise in rabbits after IV administration of the BCG preparations. In a skin reactivity assay, reactions were found acceptable for all preparations when compared with a reference batch. The results of the immunostimulation and antitumor studies can be summarized as follows. All four batches induced a specific delayed-type hypersensitivity reaction to PPD, indicating the induction of cell-mediated immunity. A stimulating effect on lymphoreticular organs was concluded from increased spleen weight and enhanced cell proliferation in draining lymph nodes. Enhanced macrophage function (phagocytosis and killing of bacteria) was demonstrated by an increased resistance to Listeria monocytogenes. YAC lymphoma target cells were killed nonspecifically by BCG-activated peritoneal exudate cells (PEC), indicating the induction of natural killing activity by BCG. Intralesional injection of BCG induced tumor regression in the guinea pig line 10 hepatocellular carcinoma, followed by immunity to the line 10 tumor. In the murine 5D04 squamous cell carcinoma, BCG had no effect on the primary tumor. However, IV-injected BCG resulted in a decreased number of lung metastases. In general, the four consecutively produced batches showed similar safety and activity in the immunostimulation assays and antitumor activity. Since only minor differences between the batches were found, which can also be attributed to the variation in experimental conditions common to biological assays, it is concluded that the vaccine batches produced show an acceptable consistency.

Abrogation of tolerance to fed antigen and induction of cell-mediated immunity in the gut-associated lymphoreticular tissues.

Abrogation of tolerance to fed antigen and induction of cell-mediated immunity in the gut-associated lymphoreticular tissues.

Detection of carcinogenic exposures by urinalysis: Induction of cell-mediated immunity

Studies were undertaken to determine whether urine collected from rats during the 24 h following exposure to the colon carcinogen 1,2-dimethylhydrazine (DMH) contained substances which would induce specific antitumor immunity. The evaluation for such components was carried out by administering the test and control urine to young male adult Fisher F344 inbred rats and then establishing the animals' antitumor cell-mediated immunity (CMI) at a 14-day post-exposure interval. The CM1 was measured by determining the injury and destruction inflicted upon cultured X-ray-induced rat small bowel adenocarcinoma target cells by peripheral blood lymphoid cells obtained from the animals exposed to the urine. A significantly increased CMI was found to be induced by the urine collected from the chemically exposed rats, thus suggesting the presence of mutagenic/carcinogenic components. In addition, exposure through the levels of CMI that were induced, with an approximate threshold detection limit of 100 μg (1.7 μmol)/kg body weight (100 ppb) to the chemical. These preliminary findings suggest that such immune measurements might serve as a basis for the development of a rapid and inexpensive bioassay for monitoring population exposures to carcinogenic substances.

Effects of carrageenan—A macrophage toxic agent—On antibody synthesis and on delayed hypersensitivity in the guinea pig

Delayed hypersensitivity reactions to the carrier and antibody mediated reactions to the carrier and to the hapten have been studied in guinea pigs treated with carrageenan, a macrophage toxic agent, before or after immunization with a hapten-carrier complex. The results show that carrageenan which acted at the afferent limb of immunity neither depressed nor enhanced delayed hypersensitivity reactions but could affect antibody formation. Macrophage functions in antibody synthesis appeared to be more sensitive to carrageenan than those involved in the induction of cell-mediated immunity. Carrageenan could provide a useful tool for studying the functional heterogeneity of macrophages during the induction of the immune response.

Preferential induction of cell-mediated immunity by chemically modified carcinoembryonic antigen.

Modification of carcinoembryonic antigen (CEA) with various chemicals was investigated. Modification of CEA with dimethylsulfate or acetic anhydride resulted in derivatives which preferentially induced delayed-type hypersensitivity (DTH) against native CEA in mice. The strength of the DTH reaction was dependent on the number and chemical nature of modifying groups as well as on the immunizing dose. The strongest DTH reaction without detectable formation of antibodies was achieved by low dose immunization using heavily methylated CEA.

The induction of cell-mediated immunity and tolerance to insulin with insulin coupled to syngeneic lymphoid cells

The induction of delayed type hypersensitivity (DTH) and tolerance to DTH against bovine insulin in mice were explored. DTH was induced with insulin in complete Freund's adjuvant (CFA) and was assessed by ear swelling in vivo and by antigen-driven cell proliferation in vitro. Using the concept that thymus cell unresponsiveness is most easily accomplished via antigen on syngeneic membranes, tolerance was induced by iv injection of syngeneic lymphoid cells which had been coupled to insulin with carbodiimide. Mice tolerized with insulin-coupled cells and then sensitized with insulin-CFA had diminished ear swelling in vivo and decreased insulin-driven cell proliferation in vitro. This unresponsiveness was antigen specific but was also inconstant in degree with regard to suppression of ear swelling, most likely because of variability in coupling of insulin to cells. Proliferative responses were more uniformly suppressed, suggesting the possibility that two target cells were being tolerized. Thus, as with other proteins, the biologically active insulin can be used to induce tolerance.

Inhibitory effect of 8-methoxysporalen plus UVA (PUVA) on the systemic induction of contact sensitivity to dinitrochlorobenzene (DNCB) in guinea pigs.

To investigate the influence of 8-MOP and UVA on the induction of cell-mediated immunity, guinea pigs, sensitized with a single injection of dinitrofluorobenzene (DNFB) in Freund's complete adjuvant (FCA) in all footpads and the nuchal skin, were treated with 8-MOP, UVA, or 8-MOP + UVA on days 0, 2, and 5 and tested with dinitrochlorobenzene (DNCB) on day 14 after sensitization. Two control groups, exposed in a covered condition to the PUVA 4000 lamp, to observe the heat effect, showed a slightly enhanced contact sensitivity in comparison to the only sensitized control group. No altered reactivity was observed after irradiation with longwave UV light alone, whereas a statistically significant enhanced resp. reduced contact sensitivity was obtained after the treatment with 8-MOP alone and the combined action of 8-MOP + UVA, respectively.

The induction of cell-mediated immunity and tolerance with protein antigens coupled to syngeneic lymphoid cells.

A mouse model of cell-mediated immunity (CMI) and tolerance to protein antigens horse gamma globulin (HoGG) and cytochrome (Cyt C) was investigated. A reliable CMI response as measured in vivo by ear swelling or by an in vitro T-cell proliferation assay could be induced by one of two methods: (a) sensitization by antigen-complete Freund's adjuvant in the base of the tail, or (b) sensitization by s.c. injection of antigen coupled to syngeneic lymphoid cells. The in vivo response exhibited characteristic CMI parameters, delayed kinetics, and transfer by viable T cells. Prior i.v. injection of HoGG-modified lymphoid cells (HoGG-LC) or Cyt C-LC before sensitization resulted in a rapidly induced, dose-dependent, antigen-specific suppression of both in vivo and in vitro manifestations of the CMI response. In addition, tolerance in this system was transferrable by an antigen-specific suppressor T cell (Ts). The Ts were found to diminish the in vivo ear swelling reaction in recipient animals, but had no effect on the in vitro T-cell proliferative response of the recipients. In contrast to the rapid development of tolerance in donor mice (phenotypic tolerance), transferrable Ts were first demonstrable 4--7 d posttolerization. This latter result indicates that at least two mechanisms of tolerance are operative in this system: the rapid induction of clone inhibition of reactive T cells and the slower induction of Ts. These results indicate again that the mode of antigen presentation is crucial in determining the immunologic outcome. In these experiments, cell-bound proteins injected subcutaneously led to delayed hypersensitivity while the same antigens injected intravenously led to tolerance. These results are considered in the light of recent experiments which show that T cells recognize antigens on cells in association with major histocompatibility complex products. We believe the following pathways are involved. In sensitization via subcutaneous injection of HoGG-LC, antigen reaches the lymph node via lymphatic pathways which lead to immunogenic macrophage-associated presentation and the activation of delayed hypersensitivity T cells (TDH). In tolerization via intravenous injection of HoGG-LC, antigen (a) reaches the lymph node via the blood, probably directly meeting the TDH, preventing its subsequent activation by immunogenic HoGG (clone inhibition) and (b) reaches the spleen, also via the blood, activating suppressor T cells.

A STUDY OF THREE PROTOCOLS OF BLOOD TRANSFUSION BEFORE RENAL TRANSPLANTATION IN THE DOG

Three protocols of blood transfusion were evaluated in a canine model for (1) the strength and breadth of leukocytotoxin induction, (2) the induction of cell-mediated immunity against the blood donors, (3) haemagglutinin production, and (4) any effect on kidney graft survival. At the end of the transfusion schedule, each dog received a kindey graft and was given azathioprine and prednisolone postoperatively. All dogs were unrelated and blood donors were not used as kidney donors. All three transfusion protocols, comprising i.v. injections of blood twice weekly or every 2 weeks from one or three donors, induced unacceptably strong and broad leukocytotoxins. All transplants performed across a positive crossmatch failed to function. However, where a negative crossmatch was available, the trend of results was that the transfused dogs had better graft survival than nontransfused animals similarly treated with azathioprine and prednisolone. Only one dog produced haemagglutinins. Several animals had positive cell-mediated immunity against the blood donors, but the response was not strong and was frequently not sustained.

Induction of abnormal immunoglobulin maturation and antibody production by persistent embryonic mumps virus infection.

Intramuscular inoculation of 19-day old chickens with heterologous erythrocytes elicited significantly lower levels of agglutinins in embryonically infected birds when compared with control birds (reciprocal ha titer 10 vs. 100, respectively, P less than 0.01). The IgG component of this antibody was substantially less in experimental chickens, 25% vs. 70% in controls. Subsequent anamnestic antibody response in experimental birds was also significantly less than control chickens (reciprocal ha titers 25 vs. 512, respectively, P less than 0.02), with continued predominance of IgM antibody in experimental chickens (70% IgM-ha) vs. controls (60% IgG-ha). Induction of cell-mediated immunity by footpad inoculation of 46-day-old birds with diphtheria-tetanus toxoid in complete Freund's adjuvant failed to discern suppression of T cell function in previously infected chicks. Before hatch, the bursae of experimental and control embryos possessed a few IgM-producing lymphoid cells in equivalent numbers. There was also no difference in the relative population of IgM-producing cells in the medullary area of bursal follicles of 7-day-old hatchling chickens, approximately 70%. However, the mean density of IgG-producing cells in the bursae of experimental chickens was less than that of control chickens, 10% vs. 19%, respectively. Consistent with persistent embryonic viral infection and altered bursal function, only IgM-producing cells were detected in the spleens of 7-day-old experimental birds. These observations suggest that persistent embryonic viral infection disturbs the function of bursal-dependent immunopoiesis in the avian host.

Cellular immunity in gnotobiotic primates induced by transfer factor

Human dialyzable transfer factor (TF) was found capable of inducing in vivo (skin test) and in vitro blastogenesis) cellular immunity in gnotobiotic nonhuman primates. Because the animals were gnotobiotic (germ-free) and had not been skin tested previously, these data support the hypothesis that induction of cell-mediated immunity in recipients of TF does not require a “priming” exposure to specific and/or cross-reacting antigens, and that this induction may be due to an antigen-specific informational effect of TF. In addition, these results support the antigenic specificity of TF, in that recipient primates developed cellular reactivity only against donor “positive” but not against donor “negative” antigens.

INDUCTION OF ABNORMAL IMMUNOPOIESIS BY PERSISTENT EMBRYONIC VIRAL INFECTION

Infection of 16-hour-old chicken embryos with mumps virus produced an initial decrease of both plasma IgM and IgG in poults with delayed maturation of normal IgG synthesis. Despite hypogammaglobulinemia, specific antiviral neutralizing antibody first appeared one week after disappearance of virus from 7-day-old hatchling chicks. Intramuscular inoculation of 19-day-old chicks with heterologous erythrocytes elicited significantly (P<.01) lower titers of agglutinins in embryonically-infected birds with a delay in transition of 19S to 7S antibody. Secondary antibody surge in experimental birds was also significantly (P<.02) less than controls with continued predominance of 19S antibody. Induction of cell-mediated immunity by footpad inoculation of 46-day-old birds with diphtheria-tetanus toxoid in complete Freund's adjuvant failed to discern suppression of T-cell function in previously infected chicks. Virus, detected in high titer throughout embryonic development, declined in the bursa of Fabricius prior to hatch. Although bursae of infected 7-day-old birds contained a slightly greater population of IgM-producing lymphoid cells than controls, distribution of IgG in bursae of experimental chicks was strikingly reduced. Consistent with persistent embryonic infection and altered bursal function, IgM alone was observed in spleens of infected chicks only.

Induction of Cellular Immunity to Herpes Simplex Virus: Relationship to the Humoral Immune Response

Abstract In vitro lymphocyte stimulation and virus-neutralization techniques were employed to study the relationship between the cellular and humoral immune responses to herpes simplex virus (HSV) in rabbits. Lymphocytes specifically sensitized to HSV were detected as early as 3 days after infection, generally before the appearance of neutralizing antibody. Neutralizing antibody levels continued to rise over the next several weeks, whereas the ability of sensitized lymphocytes to respond to viral antigens markedly decreased. Reinfection 60 days after the primary infection resulted in a sharp increase in the responsiveness of the lymphocytes to viral antigens. The induction of cell-mediated immunity and the responsiveness of sensitized lymphocytes to viral antigens appears to be intimately related to the physical state of the virus. Animals inoculated with infectious HSV developed both cellular and humoral immunity; animals inoculated with UV-inactivated HSV developed a cellular immune response, but little if any neutralizing antibody; animals inoculated with HSV complexed with anti-HSV antibody developed neither a cellular nor a humoral immune response. In vitro, specifically sensitized lymphocytes could be stimulated by virus and by virus bound to cells, but not by cell-bound virus that had been incubated with antiviral antibody. These observations suggest that antiviral antibody can affect both the induction of cell-mediated immunity and the responsiveness of specifically sensitized lymphocytes to viral antigens bound to cells.

Stimulation of rat lymphocyte proliferation by hydrocortisone during the induction of cell-mediated immunity in vitro.

Stimulation of rat lymphocyte proliferation by hydrocortisone during the induction of cell-mediated immunity in vitro.

Induction of cell-mediated immunity against leukemia EL4 in C57BL mice.

Induction of cell-mediated immunity against leukemia EL4 in C57BL mice.

Induction of Cell-Mediated Immunity and Tolerance to Homologous Collagen in Guinea Pigs: Demonstration of Antigen-Reactive Cells for a Self-Antigen

Abstract Although normal guinea pigs exhibit no immunity against heterologous (human, mouse) and homologous collagens, cell-mediated immunity to these collagens can be induced in these animals after immunization with a heterologous (human) or the homologous (guinea pig) collagen in Freund's complete adjuvant. Furthermore, guinea pigs may be made specifically tolerant of their own collagen, and such tolerance is not broken by the subsequent induction of cellular immunity to a cross-reacting antigen, the human collagen. These results demonstrate the presence in guinea pigs of antigen-reactive cells capable of recognizing a self-antigen, with the possibility of subsequent induction of either immunity or tolerance, and argue against the assumption that self-tolerance is due to the absence of specific antigen-recognition cells.

Immunosuppression in Gambian trypanosomiasis

Cellular and humoral immune responses were studied in 38 patients with Gambian trypanosomiasis and compared with those of 43 matched controls. Expression of cell mediated immunity, induction of cell mediated immunity and expression of humoral immunity were all impaired in the patients with trypanosomiasis. It is suggested that immunosuppression induced by T. gambiense may contribute to the increased susceptibility to secondary infection observed in patients with African trypanosomiasis.