Regulation of the IgE antibody response in mice. II. Radioresistance of established IgE antibody production.

The protracted IgE anti-ovalbumin (OA) response given by BDF1 mice was studied using an adoptive transfer model. Spleen cells taken from immunized BDF1 mice can produce IgE antibody in irradiated recipients without further overt antigenic challenge. Depletion of macrophages in active spleen cell suspensions did not diminish the capacity of the remaining cells to give an adoptive response. Evidently the cells subserving the adoptive response are not fully developed in donor mice until 4 weeks after immunization, since spleen cells removed at shorter intervals after immunization gave either no or weak adoptive responses. The production of IgE antibody in irradiated recipient mice is prevented if transferred B or T lymphocytes are treated in vitro with either gamma irradiation or mitomycin C, suggesting proliferation of both B and T lymphocytes is essential for the adoptive response to develop. However, the requirement for proliferation is only transient, since one IgE antibody production reached a steady state in the adoptive recipients, it manifested extreme resistance to high dose irradiation. Whole body irradiation of 800 and 1000 rad was without effect on sustained IgE production. This latter observation was valid for both intact mice which were irradiated 8 weeks after immunization and also for irradiated adoptively immunized mice. It is suggested that the IgE anti-OA antibody measured in serum of BDF1 mice several months after immunization with 1 microgram OA and 1 mg Al(OH)3 is the product of long-lived antibody secreting cells.     

Heterogeneity of populations of antibody-forming cells fractionated by glass bead columns

Spleen cell suspension, obtained from mice immunized 2–4 days previously with sheep erythrocytes, were filtered on glass bead columns. The proportion of cells which adhered to the column rose during the first 3 days to about 45%, compared with 8% in controls. This adherent fraction was shown to be relatively rich in antibody-forming cells as judged by immunocyto-adherence. After transfer to lethally irradiated recipients, cells of this fraction formed antibody which was detectable in the serum from 24 hours onwards. Cells of the non-adherent fraction also form antibody in irradiated recipients, but not before the 4th day after transfer.     

Androstenediol stimulates myelopoiesis and enhances resistance to infection in gamma-irradiated mice

The ionizing radiation-induced hemopoietic syndrome is characterized by defects in immune function and increased mortality due to infections and hemorrhage. Since the steroid 5-androstene-3beta, 17beta-diol (5-androstenediol, AED) modulates cytokine expression and increases resistance to bacterial and viral infections in rodents, we tested its ability to promote survival after whole-body ionizing radiation in mice. In unirradiated female B6D2F1 mice, sc AED elevated numbers of circulating neutrophils and platelets and induced proliferation of neutrophil progenitors in bone marrow. In mice exposed to whole-body (60)Co gamma-radiation (3 Gy), AED injected 1 h later ameliorated radiation-induced decreases in circulating neutrophils and platelets and marrow granulocyte-macrophage colony-forming cells, but had no effect on total numbers of circulating lymphocytes or erythrocytes. In mice irradiated (0, 1 or 3 Gy) and inoculated four days later with Klebsiella pneumoniae, AED injected 2 h after irradiation enhanced 30-d survival. Injecting AED 24 h before irradiation or 2 h after irradiation increased survival to approximately the same extent. In K. pneumoniae-inoculated mice (irradiated at 3-7 Gy) and uninoculated mice (irradiated at 8-12 Gy), AED (160 mg/kg) injected 24 h before irradiation significantly promoted survival with dose reduction factors (DRFs) of 1.18 and 1.26, respectively. 5-Androstene-3beta-ol-17-one (dehydroepiandrosterone, DHEA) was markedly less efficacious than AED in augmenting survival, indicating specificity. These results demonstrate for the first time that a DHEA-related steroid stimulates myelopoiesis, and ameliorates neutropenia and thrombocytopenia and enhances resistance to infection after exposure of animals to ionizing radiation.     

T cell necessity in the pathogenesis of experimental autoimmune encephalomyelitis in mice.

Cellular transfer of experimental autoimmune encephalomyelitis (EAE) was effected in mice with lymph node and spleen cells from appropriately immunized donors. In contrast to lymphoid cells, immune serum did not transfer this autoimmune disease nor did serum have any facilitating or inhibitory effect on the capacity of lymphoid cells to transfer EAE. Transfer of EAE was effected in normal mice, lightly irradiated (350 rad) and lethally irradiated (850 rad) and bone marrow-protected mice, but not in mice which had been given 850 rad total-body irradiation. There was a striking augmentation of severity of transferred EAE in the lightly irradiated recipients, possibly attributable to selective radiosensitivity of suppressor T cells. Cell-mediated immunity but not circulating antibody to basic protein of myelin was demonstrated in recipients with transferred EAE. The immune lymphoid cells responsible for transfer of EAE were T lymphocytes. Thus transfer was successful after passage of sensitized cells through anti-immunoglobulin columns and was abrogated following treatment with anti-Thy-1 serum and complement. Neonatally thymectomized mice failed to develop either EAE, cell mediated immunity or humoral antibody against myelin basic protein (BPM). Inhibition of EAE and immune responsiveness was solely due to the removal of the source of thymus lymphocytes, because reconstitution of neonatally thymectomized mice with T lymphocytes completely restored these functions. It is concluded that T lymphocytes are required for the production and adoptive transfer of EAE, for the development of cell-mediated immunity to BPM and for the production of antibody to BPM.     

柯萨奇病毒B3 VP1蛋白、rAd/VP1和pcDNA3/VP1的免疫效果比较

目的 观察柯萨奇病毒B3(Coxsackievirus B3,CVB3)衣壳蛋白VP1、表达VP1蛋白的重组腺病毒rAd/VP1和重组质粒pcDNA3/VP1的免疫效果.方法 用原核细胞表达VP1蛋白并纯化、扩增重组腺病毒rAd/VP1,扩增并提取真核表达质粒pcDNA3/VP1.BALB/c小鼠随机分为4组,每组18只,分别在股四头肌注射VP1蛋白、rAd/VP1、pcDNA3/VP1和PBS.VP1蛋白组和pcDNA3/VP1组免疫3次,间隔3周;rAd/VP1组免疫2次,间隔2周.VP1蛋白、pcDNA3/VP1和rAd/VP1每次每只注射剂量分别为50μg、100μg和1.2×107PFU.用ELISA法和微量中和试验法检测各次免疫后血清CVB3特异性IgG抗体和中和抗体滴度;末次免疫后3周,CCK-8法检测脾脏淋巴细胞的CTL杀伤活性;用致死量CVB3攻击小鼠后,检测血中病毒滴度并观察动物的存活情况.结果 VP1蛋白组血清特异性IgG抗体和中和抗体滴度明显高于其他实验组(P＜0.05),而脾脏淋巴细胞CTL杀伤活性低于rAd/VP1组(P＜0.05);致死量病毒攻击后,VP1蛋白组血中病毒滴度低于pcDNA3/VP1和rAd/VP1组(P＜0.05),生存率明显高于这两组(P＜0.05).结论 VP1蛋白疫苗能诱导较高水平的体液免疫应答,对动物有明显的免疫保护作用,免疫效果优于质粒pcDNA3/VP1和重组腺病毒rAd/VP1.

Abstract：

Objective To compare the immune effects of Coxsackievirus B3 (CVB3) capsid protein VP1 expressed bacterially, recombinant adenovirus rAd/VP1 and recombinant plasmid pcDNA3/VP1which express VP1 protein in mice. Methods After expressed in prokaryotic cells, VP1 protein was purified. Recombinant adenovirus rAd/VP1 and recombinant plasmid pcDNA3/VP1 were amplified and extracted. Six to 8-week-old, male BALB/c mice were divided into four groups randomly. Each group contained 18 mice. The mice of pcDNA3/VP1 group or VP1 protein group were immunized intramuscularly with three injections at three weeks apart, of recombinant plasmid pcDNA3/VP1 at a dose of 100 μg/mouse or recombinant protein VP1 at a dose of 50 μg/mouse. The mice of rAd/VP1 group were immunized intramuscularly twice at two weeks interval with rAd/VP1 at a dose of 1.2 × 107 PFU. The control group was mock-immunized with 100 μl of PBS intramuscularly. Mice were bled from the retroorbital sinus plexus every two weeks after each immunization. ELISA and micro-neutralization test were used to detect levels of CVB3-specific IgG antibody and neutralizing antibody titers in the sera of immunized mice. Three weeks after the last immunization, the cytotoxic T lymphocyte(CTL) killing activity of spleen lymphocytes was detected with CCK-8 assay. Subsequently, virus titers in the sera of immunized mice were determined by the 50% cell culture infective dose( CCID50 ) assay on HeLa cell monolayers and percentage of animals surviving were observed after lethal CVB3 attack over a period of 21 days. Results The titers of specific IgG antibody and neutralizing antibody in sera of VP1 protein immunized mice were higher than other groups( P ＜0.05 ). While CTL killing activity of spleen lymphocytes of VP1 protein immunized mice was lower than mice in rAd/VP1 group( P ＜0. 05). Virus titers in sera of VP1 protein immunized mice were lower than the mice in pcDNA3/VP1 or rAd/VP1 groups ( P ＜ 0.05 ), while survival rate was significantly higher than these two groups ( P ＜ 0.05 ).Conclusion VP1 protein induced higher level of humoral immune response and acquired obvious immune protection effects in mice. The immunizing potency of VP1 protein vaccine surpassed plasmid pcDNA3/VP1or recombinant adenovirus rAd/VP1. It appeared to be a promising candidate among the three different vaccines.     

Post-immune UV irradiation induces Tr1-like regulatory T cells that suppress humoral immune responses

It is well documented that UV radiation present in sunlight suppresses immune responses, especially T(h)1-driven cellular immune responses, resulting in the exacerbation of skin cancer and infectious diseases. However, the effects of UV irradiation on humoral immune responses remain less clearly defined. In addition, the majority of studies documenting immunosuppressive effects of UV irradiation has been demonstrated in animals exposed to UV radiation before immunization. In the present study, therefore, we examined the effects of UV irradiation on humoral immune responses in mice that had been immunized before UV irradiation. Both T(h)1- and T(h)2-associated Ig responses were significantly suppressed by UV irradiation given 7 days after immunization in an antigen-specific manner. Adoptive transfer experiments revealed that CD4(+) T cells from UV-irradiated mice are responsible for the UV-induced suppression of antibody responses. These CD4(+) regulatory T cells suppressed proliferation of conventional CD4(+) T cells in vivo and in vitro and contained IL-10-producing cells that did not express Foxp3. Mice depleted of CD25(+) cells also exhibited reduced antibody responses by UV irradiation. Finally, we showed that CD4(+) T cells from UV-irradiated mice treated with anti-IL-10 mAb failed to suppress antibody responses upon transfer. These results indicate that UV irradiation after immunization suppresses T(h)1- and T(h)2-mediated humoral immunity via the generation of Tr1-like regulatory T cells, in the process of which IL-10 appears to be important. Possible detrimental effects of UV irradiation after vaccination are also discussed.     

T-cell repopulation following neonatal injection of non-obese diabetic (NOD) mice with anti-T-cell antibodies.

Non-obese diabetic (NOD) mice injected with CD3 antibody as newborns have a reduced incidence of diabetes, raising the possibility that the neonatal injection caused a long-lasting change in circulating T cells. The present study shows that NOD and BALB/c mice injected with soluble CD3 antibody in the first 2 days of life sustained an 80-95% reduction in the number of circulating T cells lasting for 2-3 weeks, with T cells returning after 4 weeks, and reaching control values after 6 weeks. The T cells which appeared in intact mice 4-6 weeks after injection showed no excess of T-cell receptor (TcR) delta expressing cells. They had a similar distribution into CD4 and CD8 subsets as uninjected controls, and a similar usage and cell surface expression of four T-cell receptor V beta families. Labelled CD3 antibody was detected in the serum for up to 2 weeks after injection into neonates and was enriched in the thymus. Adoptively transferred T cells continued to be cleared from the circulation for 4 weeks following antibody injection. The properties of T cells which had been exposed to CD3 neonatally were investigated in animals who were first injected with CD3 antibody and then thymectomized. These animals had reduced numbers of T cells at 12 weeks of age. The surviving T cells showed a Ca2+ flux when stimulated but their proliferation in response to concanavalin A (Con A) was reduced, even in the presence of irradiated accessory cells or T-cell supernatant co-stimulator factors. Although the representation of four different V beta families was the same as in the uninjected controls, the density of expression of the T-cell receptor was reduced. The data indicate that the limited number of T cells which survive the injection are functionally deficient and that an intact thymus is required for full T-cell repopulation following neonatal CD3 injection into NOD mice.     

Participation of a chicken thymocyte antigen in intrathymic differentiation of T cells in vivo.

The participation of CETHB1 antigen in the intrathymic development of T cells was analysed in sublethally X-ray irradiated chickens and normal embryos which were inoculated with anti-thymocyte monoclonal antibody CETHB1. When chickens were given a sublethal X-ray irradiation on the day of hatchings immature thymo-cytes existed prominently in the thymus up to 3 weeks after irradiation. The inoculation of CETHB1 monoclonal antibody on days 14 and 18 after irradiation caused an increase of CD4(-) CD8(-) cells and a decrease of CD4 (+) CD8 (+) cells as compared to changes in control chickens. However, expression of T cell receptors CD3, alphabetaTCR, and gammadeltaTCR was not influenced. Inoculation of the monoclonal antibody on embryonic days 13 to 16 resulted in a decrease of CD4 (+) CD8(-) cells and an increase of CD4(-)CD8(-) and CD4 (+) CD8(+) cells after hatching. Thus, the binding of CETHB1 monoclonal antibody to thymocytes can inhibit the differentiation of both CD4(-)CD8(-) and CD4 (+) CD8(+) cells to CD4 (+) CD8(+) and CD4 (+) CD8(-) or CD4(-)CD8(+) cells, respectively. These results suggest that CETHB1 antigen participated in the growth and differentiation of thymocytes in the thymic microenvironment.     

Modulation of immunity to Borrelia burgdorferi by ultraviolet irradiation: Differential effect on Th1 and Th2 immune responses

Ultraviolet B (UVB) radiation suppresses the delayed-type hypersensitivity (DTH) response to alloantigen by a mechanism involving interleukin (IL)-10. It has been hypothesized, based on this result, that UV irradiation shifts the immune response from a Th1 to a Th2 response. We tested this hypothesis using Borrelia burgdorferi (Bb) as an antigen under conditions where both DTH and antibody responses could be assessed. Mice were irradiated with a single dose of UV and then immunized with Bb in complete Freund's adjuvant (CFA). DTH was assessed by footpad challenge. At various time points thereafter, mice were bled, and the serum antibodies to Bb were quantitiated. Only IgG1, IgG2a, and IgG2b were produced in response to Bb. The IgG2a and IgG2b antibody responses, as well as the DTH response to Bb, showed UV dose-dependent reductions after UV irradiation. The primary IgG1 response to Bb was very low and was unaffected by UV irradiation; however, the IgG1 secondary response was elevated in UV-irradiated mice. Injection of anti-IL-10 antibody into UV-irradiated mice within 24 h after UV exposure restored the DTH response, as well as the IgG2a and IgG2b antibody responses. In addition, injecting recombinant murine IL-10 mimicked some of the effects of UV radiation. Our results support the hypothesis that in vivo, UV irradiation down-regulates Th1 immune responses, while leaving Th2 responses intact, and suggest that IL-10 is an important mediator of this effect.     

Suppression of IgE antibody production after exposure to ozone in mice

The effect of ozone exposure on IgE antibody production with aerosolized ovalbumin (OA) administration was investigated in Balb/c mice. Mice were continuously exposed to 0.8 ppm ozone for 1, 2, or 4 weeks, respectively, and subsequently aerosolized OA was administered through the respiratory tract for 6 min with a nebulizer. The mice were then immunized intraperitoneally 1 week later with OA. IgE antibody production was suppressed in ozone-exposed mice. However, no significant difference in the primary IgE antibody production by intraperitoneal immunization alone with OA was observed between ozone-exposed mice and nonexposed mice. In order to elucidate the suppressive mechanism of IgE antibody production, hapten-carrier antigenic system was used. It is shown that the induction of helper T cell function was suppressed if the aerosolized carrier protein was administered before intraperitoneal immunization in the mice exposed to ozone. These results suggest that ozone exposure has the effect on the stage of administration of inhaled antigen and the quite insignificant effect on the IgE antibody production after intraperitoneal immunization with OA.     

Immunity to Plasmodium berghei exoerythrocytic forms derived from irradiated sporozoites

 The nature of immunity generated by Plasmodium berghei exoerythrocytic (EE) stages developing from irradiated sporozoites was studied using in vivo parameters of host protection on immunization with irradiated sporozoites and in vitro parameters of inhibition of sporozoite invasion and EE form development by serum antibodies from immunized mice. On in vivo challenge of immunized mice by sporozoites, protection was observed in an irradiation-dose-dependent manner. This finding stresses that protection is dependent on the irradiation dose of sporozoites that allows sporozoite penetration yet controls EE form development within the liver. Using the human hepatoma line Hep G2 as host cells in vitro, we observed that serum antibodies raised in mice immunized with irradiated sporozoites reacted with sporozoite- and hepatic-stage parasites in an immunofluorescent antibody test (IFAT). No reactivity was observed with blood-stage parasites. Serum antibodies from mice immunized with 6- to 18-krad-irradiated sporozoites inhibited sporozoite invasion and caused severe inhibition of EE form development in hepatoma cells, pointing to the antigenic content of EE forms developing from irradiated sporozoites (irra EE forms) as critical immunogens. Moreover, in an enzyme-linked immunosorbent assay (ELISA), serum antibodies raised to 12-krad-irradiated sporozoites showed reactivity to synthetic peptides representing the conserved Region II sequences of the P. falciparum circumsporozoite (CS) protein as well as the P. falciparum liver-stage-specific antigen (LSA-1)-based repeat sequences, thus implicating an important role for both the sporozoite and the hepatic stage in protection. Received: 21 June 1995 / Accepted: 27 Oktober 1995     

Translocation of Escherichia coli from the gastrointestinal tract to the mesenteric lymph nodes in gnotobiotic mice receiving Escherichia coli vaccines before colonization.

Germfree mice were immunized orally or intraperitoneally for 6 weeks with heat-killed vaccines of indigenous Escherichia coli or nonindigenous E. coli O 127: B8 before colonization with these strains. The mice exhibited increases in specific serum antibodies and intestinal immunoglobulin A reacting with the E coli antigens. Prior immunization did not reduce the gastrointestinal population levels of the E. coli strains attained 3 and 7 days after colonization. Neither oral nor intraperitoneal immunization with the E. coli strains before colonization decreased the incidence of bacterial translocation to the mesenteric lymph nodes or reduced the number of viable E. coli cells per mesenteric lymph node. There also was no relation in individual mice between serum antibody titers and the numbers of viable E. coli cells translocating to the mesenteric lymph nodes. Thus, prior vaccination with E. coli in this study did not decrease the incidence or reduce the numbers of viable E. coli translocating to the mesenteric lymph nodes in gnotobiotic mice monoassociated with E. coli.     

Gamma-irradiated scrub typhus immunogens: development of cell-mediated immunity after vaccination of inbred mice.

Mice immunized with three injections of gamma-irradiated Karp strain of Rickettsia tsutsugamushi were evaluated for the presence of cell-mediated immunity by using delayed-type hypersensitivity, antigen-induced lymphocyte proliferation, and antigen-induced lymphokine production. These animals also were evaluated for levels of circulating antibody after immunization as well as for the presence of rickettsemia after intraperitoneal challenge with viable Karp rickettsiae. After immunization with irradiated Karp rickettsiae, a demonstrable cell-mediated immunity was present as evidenced by delayed-type hypersensitivity responsiveness, lymphocyte proliferation, and production of migration inhibition factor and interferon by immune spleen lymphocytes. Also, a reduction in circulating rickettsiae was seen in mice immunized with irradiated rickettsiae after challenge with 1,000 50% mouse lethal doses of viable, homologous rickettsiae. All responses except antibody titer and reduction of rickettsemia were similar to the responses noted in mice immunized with viable organisms. Antibody levels were lower in mice immunized with irradiated rickettsiae than in mice immunized with viable rickettsiae. Furthermore, mice that were immunized with viable rickettsiae demonstrated markedly lower levels of rickettsemia after intraperitoneal challenge compared with either mice immunized with irradiated rickettsiae or nonimmunized mice.     

Effects of Immunization of Mothers on the Immune Reaction of Their Offspring: Inhibition of Immune Responses of Offspring Caused by Antibody Imported Through the Milk

ABSTRACT: Effects of immunization of pregnant AKR mice with nucleated chicken erythrocytes (CRBC) on immune responses of their offspring were examined. Antigen-specific reduction of generation of cytotoxicity and plaque forming cells (PFC) was demonstrated in the offspring at 8 weeks after birth, and lasted for 15 weeks. Cross-fostering experiments and cell transfer experiments showed that such suppression would be induced by antibody contained in the milk of immunized mothers rather than suppressor cells. Activities to enhance opsonization and to mediate antibody-dependent cell-mediated cytotoxicity (AI)CC) were demonstrated in the serum of such offspring before challenge with CRBC. Delayed footpad reaction (DFR) was maintained at the normal level in such offspring of immunized mice.     

Ontogeny of B-lymphocyte function. IX. Difference in the time of maturation of the capacity of B lymphocytes from foetal and neonatal mice to produce a heterogeneous antibody response to thymic-dependent and thymic-independent antigens.

The ontogeny of the capacity of the B-lymphocyte population to produce a response which is heterogeneous with respect to antibody affinity was studied in a cell transfer system. Lethally irradiated mice were reconstituted with B cells from donors of various ages, together with adult thymus cells when the response to T-dependent antigens was studied. The animals were immunized with one of a variety of antigens one day after cell transfer and the distribution of their splenic plaque-forming cells (PFC) with respect to affinity was assayed, by hapten inhibition of plaque formation, 2 to 3 weeks after immunization. Mice reconstituted with B cells from neonatal donors produced a response of low affinity and restricted heterogeneity. With four different thymic-dependent antigens (DNP-BGG, F-BGG, DNP-KLH and Dan-KLH) the splenic B-cell population acquired the capacity to reconstitute irradiated mice to produce a normal adult-like, highly heterogeneous, high affinity PFC response between 7 and 10 days after birth. The capacity to produce a heterogeneous response to the thymic-dependent protein antigen BGG matured just slightly later between 10 and 14 days of age. The bone marrow matures with regard to the capacity to reconstitute irradiated mice to give a heterogeneous response several days after the spleen, possibly as a consequence of the redistribution of peripheral B cells to the bone marrow. In contrast, maturation of the capacity of the splenic B-cell population to reconstitute irradiated recipients to give a heterogeneous, adult-like PFC response to three 'thymic-independent' antigens (TNP-PA, DNP-Ficoll and TNP-BA) takes place considerably later (between 3 and 4 weeks of age). These results suggest that the population of B-cell precursors which responds to thymic-dependent antigens may represent a different subpopulation of B cells from the population that responds to thymic independent antigens. Furthermore, the results suggest that these B-cell subsets mature at different times, presumably under independent controls.     

T-cell modulation of the murine antibody response to Neisseria meningitidis group A capsular polysaccharide.

T-cell modulation of the antibody response of BALB/c mice to group A meningococcal capsular polysaccharide (PS) was examined by using an enzyme-linked immunosorbent assay. An optimal dose (5 micrograms) of antigen induced an immunoglobulin M (IgM) response of short duration; no IgG or IgA antibody could be detected. The capacity to produce serum antibody begins at about 3 weeks of age. Concanavalin A (ConA) inhibited the magnitude of the response by 40 to 60% when given at the time of immunization; it enhanced the response two- to eightfold when given 2 days after PS. T-cell-mediated suppression could be transferred to naive mice by injection of spleen cells from low-dose-primed mice. A secondary antibody response could be induced by immunization with live meningococci. Here, the IgM response was 8- to 10-fold greater than that of mice given an optimal dose of PS; IgG antibody against group A PS increased 1 week after immunization to levels that were 100- to 1,000-fold greater than those of mice immunized with PS. The antibody response could not be augmented by multiple injections of PS; suppression occurred after low-dose priming or hyperimmunization with PS. These studies indicate that the antibody response to PS is not completely T-cell independent; rather, it is inhibited and amplified by T cells.     

Enhancement of lung colony formation by admixing irradiated with viable tumor cells: dependence on host status

The study was designed to determine whether whole-body irradiation or stimulation of the reticuloendothelial system of mice influences the ability of heavily irradiated tumor cells to enhance formation of artificial metastases when given simultaneously with viable tumor cells. Experiments were performed with a nonimmunogenic sarcoma syngeneic to C₃Hf/Kam mice. Whole-body irradiation augmented and stimulation of the reticuloendothelial system abolished the metastasis-enhancing effect of tumor cells. Another observation was that heavily irradiated tumor cells can enhance formation of metastases if given i.v. within several hours before or after i.v. injection of tumor cells.On leave of absence from Chiba University, Department of Pediatric Surgery, 8-1, Inohana-1-chome, Chiba-shi, Japan.     

Immune response of neonates to pneumococcal polysaccharide-protein conjugate.

Immune responses were studied in adult and young mice exposed to pneumococcal 6A and 19F polysaccharides (PSs), as well as 19F PS conjugated to proteins, e.g. human immunoglobulin G (HIgG), pneumococcal R61 cell wall polypeptide, and bovine serum albumin (BSA). Significantly higher IgM and IgG2 antibody titres were induced in mice receiving 19F PS-protein conjugates than in the control group receiving 19F PS alone. Maternal immunization with 19F PS-HIgG conjugate elicited a low immune response in the offspring. However, when young mice from immunized mothers were given and additional dose of polysaccharide-protein conjugate, they gave an antibody response greater than that of mice not given additional immunogen. Similarly, young mice exposed to 14-valent pneumococcal vaccine during gestation produced higher antibody response to 6A and 19F PSs. Secondary immunization of 19F PS or PS-protein conjugate at 1 or 2 weeks after primary immunization did not enhance antibody formation but rather suppressed the immune response to that polysaccharide.     

Protection of mice against brucellosis by intranasal immunization with Brucella melitensis lipopolysaccharide as a noncovalent complex with Neisseria meningitidis group B outer membrane protein

Intranasal immunization of mice with purified Brucella melitensis lipopolysaccharide (LPS) as a noncovalent complex with Neisseria meningitidis group B outer membrane protein (GBOMP) elicited a high-titer anti-LPS systemic antibody response and a significant mucosal antibody response. The anti-LPS immunoglobulin G (IgG) antibody was predominantly of the IgG1 subtype, although there was some response of the IgG2a, IgG2b, and IgG3 subtypes. The antibody titer remained high for 16 weeks postimmunization. Immunized mice and sham-immunized control mice were challenged intranasally with 10(4) CFU of virulent B. melitensis strain 16 M 4 weeks after the second dose of vaccine. The numbers of bacteria in lungs, livers, and spleens at 3 days, 9 days, and 8 weeks postchallenge were determined. Bacteria were found in lungs of all mice on day 3, but there was no disseminated infection of liver or spleen. By day 9, 40% of the mice had infected spleens and livers. At 8 weeks postchallenge, spleens of 25 of 62 immunized mice were infected, compared to 61 of 62 control mice (P < 0.0001). The livers of 12 of 43 immunized mice were infected, compared to 22 of 36 control mice (P = 0.005). In contrast, the lungs of 26 of 46 immunized mice were still infected, compared to 27 of 44 control mice. The numbers of bacterial CFU in lungs of immunized and control animals were identical. These studies show that intranasal immunization with B. melitensis LPS-GBOMP subunit vaccine significantly protects mice against intranasal challenge with virulent B. melitensis. Vaccination reduces bacterial dissemination to spleen and liver but has no effect on the course of lung infection.     

Antibody formation by adoptively transferred mouse peripheral blood leucocytes

Peripheral blood leucocytes from C3H mice that had been injected intraperitoneally with bovine serum albumin in Freund's adjuvant were transferred to irradiated, syngeneic recipients. Determination of bovine serum albumin antibody titres in the recipients showed that as the time between immunization and transfer increased, fewer peripheral blood leucocytes were needed to produce appreciable amounts of antibody. Secondary stimulation of the donor mice before transfer with aqueous bovine serum albumin resulted in greater antibody synthesis in the recipient.

When the peripheral blood leucocytes from mice immunized with bovine serum albumin were mixed with 0.1 mg of the antigen in vitro and the mixture injected into recipients no detectable antibody was produced. An in vitro booster of 0.05 mg bovine serum albumin resulted in greatly increased amounts of antibody when compared to peripheral blood leucocytes transferred without added antigen.