Stimulation of Antibacterial Vaccination in Mice by Polyadenylic Acid: Polyuridylic Acid Complex

The effect of polyadenylic acid:polyuridylic acid complex (poly A:U) on immunization was investigated in mice vaccinated by killed Brucella melitensis cells suspended in incomplete adjuvant or in saline. Addition of 300 mug of poly A:U to vaccines rendered 3 x 10(8)B. melitensis cells in saline as immunogenic as 3 x 10(11) cells in oil adjuvant against a severe B. abortus challenge. In the mouse and Brucella system, poly A:U exerts an adjuvant effect on immunity but does not stimulate production of circulating antibodies that could be demonstrated at the time of autopsy.     

Stimulation of Resistance of Immunocompromised Mice by a Muramyl Dipeptide Analog

L18-MDP(Ala), a synthetic derivative of muramyl dipeptide, enhanced resistance against Escherichia coli and Candida albicans infections in aged mice and younger adult mice whose defense mechanism(s) had been depressed by X-ray irradiation or by treatment with cyclophosphamide.     

Vaccination Against Spontaneous Abortion in Mice by Preimmunization With an Anti-diotypic Antibody

ABSTRACT: CBAE/J females mated with DBA/2 display a high level of fetal wastage which can be corrected by anti-Balb/c vaccination. A batch of CBA/J anti-(CBA/J anti-Balb/c) antiserum was raised. This serum was characterized as anti-idiotypic by various techniques, including a solid-phase radioimmunoassay. Such a serum proved to confer protection against resorbtions when injected into CBA/J mice mated with DBA/2. However, the kinetics of the effect pointed to the need for administration in early pregnancy for successful protection. The significance of these data, and the possible mechanism(s) by which the serum acts, are discussed.     

T细胞接种对SLE样小鼠防治作用的探讨

本文在空肠弯曲菌（CJ-S131）免疫诱导的小鬼SLE样综合征模型上,观察了T细胞接种（T CellVaccination,TCV）的预防和治疗作用。用于 TCV的细胞为 CJ-S131预致敏的同系小鼠 T细胞。结果显示TCV可明显地抑制CJ-S131诱导的特异性迟发型超敏反应,相反却显著地增强抗dsDNA抗体和抗外膜蛋白抗体生成。因此TCV对SLE样小鼠没有预防及治疗作用。本文对此现象进行了讨论。     

Generation and Maintenance of Immune Interferon-Producing Cells Induced by Allogeneic Stimulation in Mice

When spleen cells derived from C57BL/6 mice immunized with L cells 7 days previously were cocultured with antigenic cells, immune interferon appeared in the culture fluid. We analyzed the tissue distribution of the immune interferon-producing cells (IIPC) which appeared in various lymphoid organs after allogeneic stimulation. Although fluid from cocultures of L-cell-sensitized thymocytes and L-cells could not detect interferon activity consistently, small numbers of IIPC could be detected by using the enumeration method of IIPC. The generation, maintenance, and nature of IIPC emerging in the spleen were different depending on how the host mice were immunized. Multiple antigenic stimulations were more effective and induced longer-lasting immune interferon production than a single stimulation. IIPC induced by a single stimulation appeared to be sensitive to cortisone, vinblastine, and cyclophosphamide and were relatively short lived. In contrast, IIPC induced by multiple stimulations seemed to be partially resistant to these drugs and long lived. When mice were immunized with intact L-cells, carrageenan, a known antimacrophage agent, had no effect on immune interferon production. However, when mice were immunized with solubilized L-cell antigen, this drug displayed a suppressive effect on immune interferon production.     

Stimulation of Rabies Vaccine in Mice by Low Doses of Polyadenylic: Polyuridylic Complex

Addition of 100 mug of polyadenylic: polyuridylic (poly A:U) complex to each dose of inactivated rabies vaccine increased immunity to rabies challenge in mice. Stimulation was also observed after addition of 10 mug of poly A:U to the vaccines. Mixtures of rabies vaccine and poly A:U lost their stimulatory properties after storage at 37 or 4 C for 1 month. However, these data are encouraging for practical use of poly A:U as an adjuvant to viral vaccines.     

Antigenic Stimulation and Blocking of Pregnancy in Mice by an Anti-Idiotypic Antibody to Progesterone

PROBLEM: The present study was carried out to see if the anti-idiotypic (anti-Id) antibody (Ab2) to progesterone could mimic the immunogenicity of the steroid hormone by giving rise to antiprogesterone antibodies (Ab3) and whether these antiprogesterone antibodies (Ab3) were biologically active. METHOD: Twenty virgin female Balb/C mice were actively immunized with the anti-Id antibody (Ab2). The antiprogesterone antibody (Ab3) titres in the serum were determined and the animals were used for fertility studies. In the passive immunization studies Balb/C female mice were injected i.p. with 100 μg of anti-Id antibody to see its effect on pregnancy. RESULTS: The actively immunized animals when mated showed 80% reduction in their fertility rate. The duration of infertility (20–121 days) in these animals could be directly correlated with the concentration of antiprogesterone antibody (Ab3). The anti-Id antibody (Ab2) blocked pregnancy in 80% of the passively immunized mice. CONCLUSION: The studies show that anti-Id antibody to progesterone could mimic the immunogenicity of progesterone and give rise to antiprogesterone antibodies (Ab3). The anti-Id antibody successfully blocked pregnancy in mice both after active and passive immunization.     

Effective, Nonsensitizing Vaccination with Culture Filtrate Proteins against Virulent Mycobacterium bovis Infections in Mice

Vaccination of mice with Mycobacterium bovis culture filtrate proteins (CFP), prepared in a variety of adjuvants (aluminum hydroxide, Quil-A, and dimethyldioctyldecyl ammonium bromide [DDA]), provided significant protection against an aerosol challenge of virulent M. bovis. Additionally, vaccination with CFP in DDA or Quil-A did not sensitize mice to M. bovis purified protein derivative.     

Stimulation of Hematopoiesis in Untreated and Cyclophosphamide Treated Mice by the Inhibition of Prostaglandin Synthesis

Abstract

Indomethacin (IN) was administered to untreated or to cyclophosphamide (CY) treated C57B1/6 mice to study the roles of prostaglandins in regulating hematopoiesis. The following hematopoietic parameters were quantitated: 1) peripheral blood leukocyte (PBL) count; 2) total nucleated cells per spleen; 3) total nucleated cells per femur; and 4) spleen weight. Assays were performed in vitro to measure the number of colony forming units (CFU) present in the bone marrow and spleen. Untreated mice administered IN had a transient rise in their PBL count. These animals also developed splenomegaly and had an increased number of nucleated cells in their spleen. All CY treated mice had a marked decrease in PBL count, spleen cellularity, bone marrow cellularity, and spleen size during the first 5 days after CY treatment. These observations were followed by hematopoietic recovery over the next 10 days. Cyclophosphamide treated mice exhibited a more rapid hematopoietic recovery when treated with IN than without IN treatment. Analysis of the CFU capacity of bone marrow and spleen cells in soft agar showed a larger number of CFU in the bone marrow and spleen of IN treated mice or of CY/IN treated mice than in animals not receiving IN. These results indicate that prostaglandins are involved in the regulation of hematopoiesis in untreated mice and that prostaglandins may limit the hematopoietic recovery of CY treated mice.     

Stimulation of Hematopoiesis in Untreated and Cyclophosphamide Treated Mice by the Inhibition of Prostaglandin Synthesis

Indomethacin (IN) was administered to untreated or to cyclophosphamide (CY) treated C57B1/6 mice to study the roles of prostaglandins in regulating hematopoiesis. The following hematopoietic parameters were quantitated: 1) peripheral blood leukocyte (PBL) count; 2) total nucleated cells per spleen; 3) total nucleated cells per femur; and 4) spleen weight. Assays were performed in vitro to measure the number of colony forming units (CFU) present in the bone marrow and spleen. Untreated mice administered IN had a transient rise in their PBL count. These animals also developed splenomegaly and had an increased number of nucleated cells in their spleen. All CY treated mice had a marked decrease in PBL count, spleen cellularity, bone marrow cellularity, and spleen size during the first 5 days after CY treatment. These observations were followed by hematopoietic recovery over the next 10 days. Cyclophosphamide treated mice exhibited a more rapid hematopoietic recovery when treated with IN than without IN treatment. Analysis of the CFU capacity of bone marrow and spleen cells in soft agar showed a larger number of CFU in the bone marrow and spleen of IN treated mice or of CY/IN treated mice than in animals not receiving IN. These results indicate that prostaglandins are involved in the regulation of hematopoiesis in untreated mice and that prostaglandins may limit the hematopoietic recovery of CY treated mice.     

Responses of the Peyer's Patches in Germ-Free Mice to Antigenic Stimulation

Lymph nodes, spleens, and Peyer's patches of germ-free mice are relatively inactive. The tissues are small and contain rare, small, indistinct, germinal zones. When exposed to antigenic stimuli (Salmonella paratyphi A and lymphocytic choriomeningitis virus), the tissues become larger and germinal zones appear coincident with antibodies in the blood. The Peyer's patches were activated if antigen was absorbed from the intestinal lumen into the circulation but not if the antigen was administered parenterally. There was no demonstrable immunological response by the germ-free mouse to Streptococcus faecalis.     

Protection against Lethal Neospora caninum Infection in Mice Induced by Heterologous Vaccination with a mic1 mic3 Knockout Toxoplasma gondii Strain

Neospora caninum and Toxoplasma gondii are closely related, obligate intracellular parasites infecting a wide range of vertebrate hosts and causing abortion and neonatal morbidity and mortality. Several lines of evidence suggest that cross immunity between these two pathogens could be exploited in the design of strategies for heterologous vaccination. We assessed the ability of an attenuated strain of T. gondii (“mic1-3KO strain”) conferring strong protection against chronic and congenital toxoplasmosis to protect mice against lethal N. caninum infection. Mice immunized with mic1-3KO tachyzoites by the oral and intraperitoneal routes developed a strong cellular Th1 response and displayed significant protection against lethal heterologous N. caninum infection, with survival rates of 70% and 80%, respectively, whereas only 30% of the nonimmunized mice survived. We report here the acquisition of heterologous protective immunity against N. caninum following immunization with a live attenuated mic1-3KO strain of T. gondii.Neospora caninum and Toxoplasma gondii are closely related apicomplexans displaying extensive morphological and genetical similarity (37). These cyst-forming coccidians of the family Sarcocystidae (11) cause similar disorders in different animals (15). Despite controversial documentation on their phylogenetic relationship (30), molecular (31) and biological studies have shown that these species have followed different evolutionary paths and have different life cycles and host preferences. Canids are the definitive hosts of N. caninum, which causes neosporosis, a major disease of cattle, whereas felids are the definitive hosts of T. gondii, which causes toxoplasmosis, a major disease of sheep, goats, and humans (10). Both parasites are responsible for important economic losses in livestock production through neonatal mortality and abortion. T. gondii also causes congenital neuropathology and opportunistic infections in immunocompromised humans (41), but there is no conclusive evidence to suggest that N. caninum can infect humans (29).Previous clinical and diagnostic studies have shown that specific antibodies directed against N. caninum or T. gondii cross-react in serological and immunohistochemical tests, suggesting a possible convergence of immune responses during infections with T. gondii and N. caninum (32, 38). It has recently been shown that antibodies directed against N. caninum antigens inhibit host cell invasion by both these parasites (22, 43). Similarly, the specific cellular responses stimulated upon experimental infections with N. caninum are also stimulated in vitro by T. gondii antigenic lysate (21, 26). Consistent with these findings, CD8⁺ T cells specific for N. caninum have been shown to protect mice against lethal T. gondii infection (19). The existence of cross-reactive epitopes between N. caninum and T. gondii antigens is supported by the high level of sequence identity between conserved proteins (13). A number of cross-reactive antigens have been identified in the micronemes, rhoptries, and dense granules of tachyzoites and in bradyzoites (2, 3, 28, 43). All these observations suggest that the conserved antigenicity between N. caninum and T. gondii might represent a rational basis for the development of efficient vaccines for the control of both parasitic diseases.A vaccine based on dead N. caninum tachyzoites is currently available for prophylaxy; this vaccine is thought to confer about 46% protection against N. caninum-induced abortion in cattle (36). However, in a number of countries, this vaccine has not been licensed, since more complete scientific documentation is required to authorize the use of a vaccine against N. caninum (8). The need for a more effective vaccine against transplacental infection in cattle is therefore of the utmost importance. Live vaccines are thought to induce complete protective immunity against N. caninum infection. In vaccination trials with the mouse model, the use of N. caninum tachyzoite crude extract as the immunogen resulted in an absence of protection against parasite-related neurological illness and death (5, 27). Such vaccinations have also proved ineffective for the prevention of abortion in cattle, even in the presence of adjuvants (42).Given that protective immunity against intracellular pathogens such as T. gondii and N. caninum involves T-cell-mediated immunity (12, 21) and that experimental evidence of protection against N. caninum transplacental transmission has been shown to involve high levels of gamma interferon (IFN-γ) production (17, 42), we propose an innovative approach based on heterologous vaccination.Taking into consideration the antigenic similarities between N. caninum and T. gondii, we used an attenuated strain of T. gondii as a heterologous vaccine against N. caninum. A mutant RH strain of T. gondii tachyzoites lacking the mic1 and mic3 genes was constructed in our laboratory, the “mic1-3KO strain.” The disruption of these two genes, both of which code for proteins involved in tachyzoite adhesion and invasion, greatly decreases virulence in mice (7). Vaccination with the mic1-3KO strain provides strong protection against chronic and congenital toxoplasmosis in mice through the induction of strong humoral and Th1 cellular immune responses (18). In this study, we used this attenuated strain as a heterologous vaccine. Our results provide evidence for protection against lethal N. caninum infection. This protection was associated with strong cross-reactive humoral and Th1 cellular immune responses, overcoming the biological and antigenic differences between the two species.     

Effect of Bordetella pertussis Vaccination in Mice and the Isolated Tracheal Response to Isoprenaline

The administration of Bordetella pertussis vaccine to mice has been associated with the development of an impaired beta-adrenoceptor responsiveness and in many respects has resembled human asthma. Trachea (n = 12) were isolated from Swiss-Webster mice 5 days following the intraperitoneal administration of 2 x 10(9) B. pertussis organisms. The tracheal smooth muscle response to carbachol was measured and compared with that found in trachea from unvaccinated mice (n = 15). The contractile response was similar in both groups. The tracheal smooth muscle relaxant effects of isoproterenol were measured in these two groups. The EC50 value for isoprenaline (6.5 x 10(-7) M) in trachea from B. pertussis treated mice was significantly (P < 0.05) greater than that noted in the control animals (2.3 x 10(-7) M). These studies demonstrated that in tracheal smooth muscle isolated from B. pertussis vaccinated mice, the relaxant effects of isoprenaline are impaired.     

Protective Effect of Vaccination with a Combination of Recombinant Surface Antigen 1 and Interleukin-12 against Toxoplasmosis in Mice

We studied the immune response induced in mice by recombinant Toxoplasma gondii surface antigen 1 (rSAG1) protein, alone or combined with interleukin-12 (IL-12) as an adjuvant, and the protective effect against toxoplasmosis. Immunization with rSAG1 alone induced a specific humoral type 2 immunity and did not protect the animals from infection. In contrast, immunization with rSAG1 plus IL-12 redirected humoral and cellular immunity toward a type 1 pattern and reduced the brain parasite load by 40%.     

Inhibition of the Multiplication of Mycobacterium leprae by Vaccination with a Recombinant M. bovis BCG Strain That Secretes Major Membrane Protein II in Mice

The ability of a recombinant Mycobacterium bovis BCG strain that secretes major membrane protein II (MMP-II) of Mycobacterium leprae (BCG-SM) to confer protection against leprosy was evaluated by use of a mouse footpad model. C57BL/6J mice intradermally inoculated with BCG-SM produced splenic T cells which secreted significant amounts of gamma interferon (IFN-γ) in response to either the recombinant MMP-II, the M. leprae-derived membrane fraction, or the BCG-derived cytosolic fraction in vitro more efficiently than those from the mice infected with the vector control BCG strain (BCG-pMV, a BCG strain containing pMV-261). A higher percentage of CD8⁺ T cells obtained from BCG-SM-inoculated mice than those obtained from BCG-pMV-inoculated mice produced intracellular IFN-γ on restimulation with the M. leprae antigens. BCG-SM inhibited the multiplication of M. leprae in the footpads of C57BL/6J mice more efficiently than BCG-pMV. These results indicate that a BCG strain that secretes MMP-II could be a better vaccine candidate for leprosy.Leprosy, which is caused by Mycobacterium leprae, is an infectious disease that still affects thousands of people worldwide. According to WHO''s weekly epidemiological report, 254,525 new cases were detected in 2007 (25). One reason why leprosy is still prevalent may be due to the inherent characteristics of M. leprae, i.e., slow growth and weak pathogenicity. It takes 12 to 14 days for M. leprae to replicate, so it is predicted that 2 to 5 years are necessary for the clinical manifestations to appear after an infection (1, 18). Likewise, it takes 6 to 8 months for the recognizable swelling of the footpad to appear in nude mice (22).Leprosy is clinically divided into two major categories: multibacillary (MB) leprosy and paucibacillary (PB) leprosy. In the lesions of patients with PB leprosy, dendritic cells (DCs) and activated T cells are involved with confining M. leprae to a localized area. These pathological observations indicate that cell-mediated reactions are triggered and that the activation of both CD4⁺ and CD8⁺ T cells is closely associated with inhibition of the spread of the bacilli. In contrast, abundant foamy macrophages loaded with bacilli but not DCs appear in the lesions of MB patients (11). It can be speculated that antigen (Ag)-presenting cells such as DCs recognize the immunodominant Ags of M. leprae and express those derivatives on their surfaces, thereby activating T cells. Previously, using T cells from patients with PB leprosy, we have identified major membrane protein II (MMP-II), also known as bacterioferritin (ML2038), as one of the immunodominant Ags (8). We found that MMP-II activates DCs through Toll-like receptor 2, leading to higher levels of expression of major histocompatibility complex class I and class II, CD86, and CD83 Ags and increased levels of production of interleukin-12 p70. Furthermore, MMP-II-pulsed DCs derived from patients with PB leprosy activated both autologous CD4⁺ T cells and CD8⁺ T cells to produce gamma interferon (IFN-γ) in amounts larger than the amounts produced by T cells from patients with MB leprosy and M. bovis BCG-vaccinated healthy individuals, indicating that T cells from patients with PB leprosy may be primed with MMP-II in vivo.The BCG vaccine has been used for the prevention of tuberculosis, although its role in the prevention of leprosy is still being debated. The protective efficacy of BCG against leprosy has been tested in several trials, including studies in the Karonga District of northern Malawi, in which 50% protection was observed (17). Through combined systematic analyses of experimental studies, Setia et al. found that the BCG vaccine had an overall level of protective efficacy of 26% against human leprosy (19). Their observational studies overestimated the protective effect at 61%. In another review of 29 studies, Zodpey reported that 44.8% of the reports indicated that the BCG vaccine had a level of efficacy of 50% or more (26). These observations indicate that improvements to the BCG vaccine are necessary to increase its protective effect. Recently, we produced a recombinant BCG strain that secretes MMP-II (strain BCG-SM, where SM indicates secreting MMP-II). Since MMP-II has the ability to ligate Toll-like receptor 2, we expected BCG-SM to highly activate human T cells. In fact, BCG-SM activated not only naïve CD4⁺ T cells but also naïve CD8⁺ T cells through DCs (9). The fact that BCG-SM was more efficient than the parental BCG strain at the activation of both subsets of naïve T cells led us to seek further insights into the protective activity of BCG-SM. In the present study, we investigated the effect of vaccination of BCG-SM on the multiplication of M. leprae in mice.     

Protection of Mice Against Vaccinia Virus by Bacterial Infection and Sustained Stimulation with Specific Bacterial Antigens

In these experiments, mice which have a strong delayed-type hypersensitivity to mycobacteria were found, when elicited with old tuberculin, to be more resistant to intravenous vaccinia virus challenge than controls. This was manifest as protection from killing when large amounts of virus were injected, or as significantly less tail swelling and damage as well as lower titers of infectious virus when a lesser inoculum was used. Preliminary experiments indicate that animals sensitized with Staphylococcus aureus and elicited with phage lysate of staphylococcus are also more resistant to vaccinia infection.