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PubMed2001

Suppository-mediated DNA immunization induces mucosal immunity against bovine herpesvirus-1 in cattle.

Mucosal surfaces are the primary sites for the transmission of infectious agents including viruses, so effective vaccines generally should induce mucosal immunity. Furthermore, noninvasive delivery is desirable because of the ease of application, the high degree of patient compliance, and the improved safety for patients and clinicians due to the elimination of needles. Unfortunately, most of the conventional vaccines are parenterally administered and result in systemic rather than mucosal immunity. Here we present the first report of mucosal immunity by noninvasive DNA immunization in a target species. As an approach to induce mucosal immunity against bovine herpesvirus-1, cows were immunized intravaginally with suppositories containing plasmid coding for glycoprotein D. Serum IgG, as well as IgA both in the serum and in the nasal fluids, were detected, which supports the contention of a common mucosal immune system. This level of immunity was of sufficient magnitude to minimize weight loss and significantly reduce the duration of virus shedding after intranasal viral challenge, which demonstrates the efficacy of suppository-based administration of DNA vaccines to target species. As this is a very practical method of delivery, it has great potential to be applied as vaccine or therapy in a variety of species.

Administration, Intravaginal↗

PubMed1999

Origins of immunity: transcription factors and homologues of effector genes of the vertebrate immune system expressed in sea urchin coelomocytes.

Echinoderms share common ancestry with the chordates within the deuterostome clade. Molecular features that are shared between their immune systems and that of mammals thus illuminate the basal genetic framework on which these immune systems have been constructed during evolution. The immune effector cells of sea urchins are the coelomocytes, whose primary function is protection against invasive marine pathogens; here we identify six genes expressed in coelomocytes, homologues of which are also expressed in cells of the mammalian immune system. Three coelomocyte genes reported here encode transcription factors. These are an NFKB homologue (SpNFKB); a GATA-2/3 homologue (SpGATAc); and a runt domain factor (SpRunt-1). All three of these coelomocyte genes respond sharply to bacterial challenge: SpNFKB and SpRunt-1 genes are rapidly up-regulated, while transcripts of SpGATAc factor disappear within hours of injection of bacteria. Sham injection also activates SpNFKB and SpRunt, though with slower kinetics, but does not affect SpGATAc levels. Another gene, SpHS, encodes a protein related to the signal transduction intermediate HS1 of lymphoid cells. Two other newly discovered genes, SpSRCR1 and SpSRCR5, encode proteins featuring SRCR repeats. These genes are members of a complex family of SRCR genes all expressed specifically in coelomocytes. The SRCR repeats most closely resemble those of mammalian macrophage scavenger receptors. Remarkably, each individual sea urchin expresses a specific pattern of SRCR genes. Our results imply some shared immune functions and more generally, a shared regulatory architecture which underlies immune system gene expression in all deuterostomes. We conclude that the vertebrate immune system has evolved by inserting new genes into old gene regulatory networks dedicated to immunity.

Adult↗

PubMed1986

Immunity to Plasmodium yoelii: kinetics of the generation of T and B lymphocytes that passively transfer protective immunity against virulent challenge.

Adoptive immunization of A/Tru mice with splenic B cells or T cells from syngeneic donors with a primary, nonvirulent, Plasmodium yoelii (17X) infection confers on these recipients the capacity to resist a challenge infection with a virulent strain (YM) of P. yoelii. Unfractionated spleen cells as well as spleen cells enriched for T or B cells capable of transferring protective immunity were detected as early as Day 7 of the primary nonvirulent infection, and reached peak levels on Day 14. Spleen cells that were harvested from donor animals after resolution of the immunizing infection [on Days 21 or 28] were incapable of transferring protective immunity. The capacity of 7-day immune spleen cells to transfer immunity could be abolished by pretreatment with mitomycin C. In addition, it was found that immunocompetent recipient mice were required for successful adoptive immunization, since thymectomized, irradiated, bone marrow reconstituted mice infused with immune spleen cells failed to survive lethal challenge infections.

Animals↗

PubMed1983

Effects of acute nitrogen dioxide exposure on cellular immunity after lung immunization.

The effects of acute NO2 exposure on antigen-specific cell-mediated lung immunity in Fischer 344 rats were evaluated. Animals were exposed for 24 hr to either room air or 5, 10, or 26 ppm NO2 before intratracheal immunization with 10(8) sheep red blood cells (SRBC). Cellular immunity was evaluated by antigen-specific lymphocyte stimulation assays of pooled lymphoid cell suspensions from either the thoracic lymph nodes or spleens. Elevated cellular immunity was observed after exposure to NO2. The ability of the 26 ppm NO2 exposure to increase cellular immunity seemed to parallel, and in some cases even exceed, that seen in control animals immunized with SRBC mixed with 2 X 10(7) heat-killed Bacillus Calmette-Guerin. These results support the theory that lung damage, and/or alterations of regulatory populations of immune cells, induced by agents such as NO2 can be responsible for the production of abnormally elevated immune responses to antigens deposited in the damaged lung.

Animals↗

PubMedDate not supplied

Anterior chamber associated immune deviation: the privilege of immunity in the eye.

Immune privilege in the anterior chamber of the eye, no longer considered a laboratory curiosity, results from an active, if deviant, systemic immune response. The specific features of this response, termed Anterior Chamber Associated Immune Deviation (ACAID) include (a) suppressed delayed hypersensitivity, (b) preserved humoral immunity, and (c) primed cytotoxic T cell responses. Induction of ACAID by intraocular antigens depends upon unique characteristics of the anterior segment of the eye and of the spleen. Evidence from animal models is presented in support of the contention that ACAID is an evolutionary adaptation of the immune response designed to provide those types of immune protection for the eye that interfere with vision as little as possible. ACAID may also have been created for the purpose of avoiding harmful immune responses (autoimmune diseases) to unique molecules of the eye (such as retinal S antigen), which the immune system never learns to regard as "Self." Because of this adaptation, the eye and the host are vulnerable to those pathogens whose elimination is dependent upon delayed hypersensitivity, such as malignant tumors and herpes simplex virus-1. As we come to understand the cellular and molecular mechanisms responsible for ACAID, a new generation of therapeutic strategies may be envisioned for certain eye diseases which are now of enigmatic cause and submit poorly to conventional therapy.

Animals↗

PubMed1992

The cellular immune response to immunization with zona pellucida antigens.

The cellular immune response of mice to porcine and rat zona pellucida and cynomolgus macaques to porcine zona pellucida antigens was evaluated. Mice mounted a vigorous cellular response to both antigens, as determined by the T cell proliferation response in vitro. There was poor cross-reactivity to murine zonae by T cells or serum antibodies from mice immunized with rat zona pellucida. Nevertheless, ovaries from the mice immunized with rat zona had significantly fewer antral follicles than adjuvant-treated controls, suggesting that the immune response to the zona antigen disrupted follicular development. T cells from two macaques that had been immunized with porcine zona pelludica proteins proliferated in vitro in response to this antigen. Both macaques also had strong antibody responses. The patterns of urinary steroid metabolites in these animals provided clear evidence of ovarian malfunction following immunization. The data indicate that a significant cellular immune response is generated upon immunization of animals with zona pellucida antigens regardless of whether the antigens are cross reactive with the host zona antigens. Whether impaired ovarian function and follicular development are related to the cellular response must be determined in future studies.

Animals↗

PubMed1992

Effects of route of immunization, adjuvant and unrelated antigens on the humoral immune response in lines of chickens selected for antibody production against sheep erythrocytes.

Effects of intramuscular (i.m.), intravenous (i.v.) and intraperitoneal (i.p.) primary immunization with the T-dependent antigen, sheep red blood cells (SRBC), was studied in two chicken lines selected for either high (H) or low (L) antibody response after i.m. immunization with SRBC. The primary route of immunization affected the line differences in the primary response and in the secondary response after i.m. reimmunization. Intravenous immunization with the T-dependent antigen bovine serum albumin (BSA) showed line differences similar to those found after i.m. or i.v. immunization with SRBC. Immunization with both the partially T-independent antigens Brucella abortus (BA) or Salmonella H-antigen (SHA) revealed no line effect. Immunization with SRBC in incomplete Freund's adjuvant (IFA) did not change the difference between lines, whereas immunization with complete Freund's adjuvant (CFA) diminished the difference between lines. It is postulated that differences in antibody production between the selected lines might be attributed to differences in T-cell activity.

Animals↗

PubMed1991

Different profiles of the human immune response to primary and secondary immunization with an oral Salmonella typhi Ty21a vaccine.

Human immune response to a secondary immunization by the oral route was studied by enumerating specific antibody-secreting cells (ASC) in the peripheral blood, believed to reflect the local immune response in the mucosa. The volunteers had been immunized 1-2 years earlier with live Salmonella typhi Ty21a given orally as three doses of vaccine in enteric-coated capsules (3 x E); their ASC and serum antibody responses have been published. In the present study 17 of the same volunteers received one booster dose of the same vaccine (B-E). Specific ASC appeared in the blood of all volunteers after vaccination, peaked on day 5 and faded away thereafter so that on day 9 specific ASC were detected in only seven subjects. The ASC responses to the single booster dose were significantly higher than those to one dose in primary immunization and at least as high as those of the same volunteers to three doses in primary immunization. Serum antibody responses were not seen in any of the vaccinees after secondary immunization, whereas after primary immunization 60% of these subjects responded. This study shows the presence of immunologic memory also in respect of the human ASC response, and confirms the separate nature of ASC and serum response.

Administration, Oral↗

PubMed2006

Intradermal and oral immunization with recombinant Mycobacterium bovis BCG expressing the simian immunodeficiency virus Gag protein induces long-lasting, antigen-specific immune responses in guinea pigs.

To develop a new recombinant BCG (rBCG) vaccine, we constructed rBCG that expresses the full-length Gag protein of simian immunodeficiency virus (rBCG-SIVGag) at a level of 0.5 ng/mg after 3 weeks of bacterial cell culture. Intradermal (i.d.) inoculation of guinea pigs with 0.1 mg of rBCG-SIVGag resulted in the induction of delayed-type hypersensitivity (DTH) responses to both purified protein derivative (PPD) of tuberculin and SIV Gag p27 protein; responses that were maintained for the duration of the 50-week study. In contrast, guinea pigs orally vaccinated with 160 mg of the same antigen exhibited a long-lasting DTH response to the SIV Gag p27 protein, but mounted no response to PPD. Proliferative responses to SIV Gag p27 and PPD antigens were detected in both i.d. and orally immunized animals; however, the levels of PPD-specific responses were significantly higher in guinea pigs immunized by the i.d. than the oral route. A significant increase in the level of PPD- and SIV Gag p27-specific IFNgamma mRNA expression was also detected in both immunization groups receiving rBCG-SIVGag. In addition, both i.d. and oral immunization with rBCG-SIVGag induced PPD- and SIV Gag p27-specific serum IgG responses. Insertion of the SIV gag gene into BCG did not appear to change the ability of rBCG-immunized animals to elicit PPD-specific immune responses. These results indicate that rBCG-SIVGag has the ability to effectively induce long-lasting, cell-mediated and humoral immunity against both viral and bacterial antigens in guinea pigs, suggesting that rBCG-Gag has the potential to elicit immunities specific not only for tuberculosis but also for HIV at human doses.

Administration, Oral↗

PubMed2005

Immunization with native surface protein NcSRS2 induces a Th2 immune response and reduces congenital Neospora caninum transmission in mice.

NcSRS2, a tachyzoite surface protein of Neospora caninum, is an immunodominant protein with respect to induction of antibody production and has a role in attachment and invasion of host cells. Native NcSRS2 was isolated from whole tachyzoite lysate antigen by affinity chromatography using NcSRS2 specific monoclonal antibody and used to immunize BALB/c mice in a congenital transmission study. NcSRS2 was a highly conserved protein as indicated by comparison of deduced amino acid sequence obtained from NcSRS2 gene sequences of 10 geographically distinct N. caninum isolates. Mice immunized with purified native NcSRS2 produced antigen-specific antibody, primarily of IgG 1 subtype. Following challenge during gestation with 10(7) tachyzoites, immunized mice had a statistically significant decreased frequency of congenital transmission compared to non-immunized mice (P<or=0.05) or mice inoculated with adjuvant alone (P<or=0.01). Decreased congenital transmission among immunized mice correlated with a predominately Th2 immune response compared to non-immunized mice as indicated by an increased ratio of interleukin 4 (IL-4) to interferon gamma (IFN-gamma) secretion from antigen-stimulated splenocytes. The results provide a rationale for NcSRS2 as a candidate subunit vaccine antigen for reduction of N. caninum congenital transmission. Furthermore, the studies suggest that a Th2 immune response, if directed against an appropriate antigen, may induce protection against N. caninum congenital infection in mice.

Animals↗

PubMed2005

Naked DNA immunization as an approach to target the generic tumor antigen survivin induces humoral and cellular immune responses in mice.

Survivin, a 16.5 kDa tumor associated antigen, is the smallest member of the inhibitor of apoptosis family that is abundantly expressed during development but essentially absent in normal adult tissues. Interestingly, survivin expression is up-regulated in virtually all types of cancers studied, as well as in vascular endothelial cells during tumor associated angiogenesis. Survivin links apoptosis to cell cycle progression and plays a pivotal role in regulation of cell proliferation. These characteristics make survivin a potentially promising generic target for cancer immunotherapy. Hence, a genetic immunization strategy to induce tumor-specific immune responses against human survivin in a pre-clinical animal model was developed. In initial studies, BALB/c mice were immunized by intramuscular injection with DNA coding for human survivin (pcDNA3.1/hSurv). In addition, a construct encoding a secreted version of survivin (pSecTag2B/hSurv) was designed. A plasmid coding for murine granulocyte-macrophage colony-stimulating factor (GM-CSF) was co-injected in both cases as a molecular adjuvant. Expression of survivin following transfection in mouse cells was corroborated. Humoral responses against human survivin were detected in mice sera using two immunization protocols (injections at 2- or 3-week intervals). The humoral response was markedly improved by secretion of survivin and co-expression of GM-CSF. The predominant antibody subclass detected in responsive mice was IgG2a, suggesting that a Th1-CD4+ cellular response had been induced. Furthermore, DNA immunization with survivin encoding vectors generated an effective CD8+ T cell response measured as an increase of cytotoxic Interferon-gamma (IFN-gamma) secreting CD8+ T cells. In conclusion, intramuscular genetic immunization of mice with human survivin encoding plasmids induced a survivin-specific humoral as well as cellular immune response in recipient mice. Secretion of survivin and co-injection of GM-CSF as a genetic adjuvant appear to be more important in generating an humoral than a cellular immune response.

Animals↗

PubMed2006

Immunization with MIC1 and MIC4 induces protective immunity against Toxoplasma gondii.

Host cell invasion by Toxoplasma gondii is tightly coupled to the apical release of micronemal proteins (MIC). In this work, we evaluated the protective effect encountered in C57BL/6 mice immunized with MIC1 and MIC4 purified from soluble tachyzoite antigens by affinity to immobilized lactose. The immunized mice presented high serum levels of IgG1 and IgG2b specific antibodies. MIC1/4-stimulated spleen cells from immunized mice produced IL-2, IL-12, IFN-gamma, IL-10, but not IL-4, suggesting the induction of a polarized Th1 type immune response. When orally challenged with 40 cysts of the ME49 strain, the immunized mice had 68% fewer brain cysts than the control mice. Immunization was associated with 80% survival of the mice challenged with 80 cysts, contrasting with 100% mortality of the non-immunized mice in the acute phase. In this phase, there was much lower parasitism in the lungs and small intestine of the immunized mice, and they did not exhibit the early-stage signs of intestinal necrosis, which was clearly detected in the control mice. Our data demonstrate that MIC1 and MIC4 triggered a protective response against toxoplasmosis, and that these antigens are targets for the further development of a vaccine.

Animals↗

PubMed2006

Immunization with SARS-CoV S DNA vaccine generates memory CD4+ and CD8+ T cell immune responses.

An effective vaccine for severe acute respiratory syndrome (SARS) will probably require the generation and maintenance of both humoral and cellular immune responses. It has been reported that after natural infection in humans and immunization in animals with SARS-CoV vaccine, antibody is produced and persistent for a long period of time. In the present study, mice were immunized i.m. with SARS-CoV S DNA vaccine, and three different methods (ELISA, ELISPOT and FACS) were used to evaluate the immune responses when the cells were stimulated in vitro with a pool of peptides overlapping entire SARS spike protein. The results show that prime-immunization with SARS-CoV S DNA vaccine can induce both CD4(+) and CD8(+) T cell responses. Boosting with the same vaccine enhances CD4(+) and CD8(+) T cell responses in both lymphoid and nonlymphoid organs and were persistent over two months. The SARS-CoV S-specific CD4(+) and CD8(+) T cells were CD62L(-), a marker for memory cells, and -30 to 50% of the cells expressed IL-7Ralpha (CD127), a marker for the capacity of effector cells to develop into memory cells. In addition, immunization with the DNA vaccine elicited high levels of antibody production. Taken together, these data demonstrate that immunization with SARS-CoV S DNA vaccine can generate antigen-specific humoral and cellular immune responses that may contribute to long-term protection.

Animals↗

PubMed2005

Cholera toxin improves the F4(K88)-specific immune response following oral immunization of pigs with recombinant FaeG.

Oral immunization of both humans and animals with non-replicating soluble antigens often results in the induction of oral tolerance. However, receptor-dependent uptake of orally administered soluble antigens can lead to the induction of an antigen-specific immune response. Indeed, oral immunization of pigs with recombinant FaeG (rFaeG), the adhesin of the F4(K88) fimbriae of enterotoxigenic Escherichia coli (ETEC), induces an F4-specific humoral and cellular immune response. This response is accompanied with a reduction in the excretion of F4(+)E. coli following challenge. To improve the immune response against F4, rFaeG was orally co-administered with the mucosal adjuvant cholera toxin (CT). Oral immunization of pigs with rFaeG and CT significantly improved the induction of an F4-specific humoral and cellular immune response and also significantly reduced the faecal F4(+)E. coli excretion following F4(+) ETEC challenge as compared to rFaeG-immunized pigs. Therefore, the present study demonstrates that CT can act in pigs as a mucosal adjuvant for antigens that bind to the intestinal epithelium by a CT-receptor-independent mechanism.

Adhesins, Escherichia coli↗

PubMed2006

Immune response in mice and cattle after immunization with a Boophilus microplus DNA vaccine containing bm86 gene.

Plasmid pBMC2 encoding antigen Bm86 from a Colombian strain of cattle tick Boophilus microplus, was used for DNA-mediated immunization of BALB/c mice, employing doses of 10 and 50microg, delivered by intradermic and intramuscular routes. Anti-Bm86 antibody levels were significantly higher compared to control mice treated with PBS. In the evaluation of immunoglobulin isotypes, significant levels of IgG2a and IgG2b were observed in mice immunized with 50microg of pBMC2. Measurement of interleukine (IL) levels (IL-4, IL-5, IL-12(p40)) and interferon-gamma (IFN-gamma) in the sera of mice immunized with pBMC2 indicated high levels of IL-4 and IL-5, although there were also significant levels of IFN-gamma. Mice immunized with pBMC2 showed antigen-specific stimulation of splenocytes according to the incorporation of bromodeoxyuridine and IFN-gamma secretion. In all trials, mice injected intramuscularly with 50microg of pBMC2 presented the highest immune response. Moreover, cattle immunized with this DNA vaccine showed antibody production significantly different to the negative control. In conclusion, these results suggest the potential of DNA immunization with pBMC2 to induce humoral and cellular immune responses against B. microplus.

Animals↗

PubMed2003

IL-12-assisted immunization generates CD4+ T cell-mediated immunity to Listeria monocytogenes.

Mice infected with virulent Listeria monocytogenes develop long-lived acquired immunity. We previously reported that acquired immunity to Listeria could also be elicited by immunizing mice with non-viable Listeria or listerial proteins/peptides in combination with IL-12. Here we show that this IL-12-assisted immunization strategy was effective in class I but not in class II MHC-deficient mice, suggesting that antigen-specific CD4(+) T cells are selectively generated using this adjuvant system. We have also evaluated the importance of endogenous production of IFN-gamma and IL-12 for the efficacy of IL-12-assisted immunization. IFN-gamma-deficient mice immunized with HKLM and IL-12 failed to produce effective Listeria-specific responses. In contrast, IL-12-deficient mice were able to generate protective antigen-specific T cell responses in response to immunization with HKLM and IL-12, indicating that exogenous IL-12 is sufficient to initiate a cytokine cascade that results in a potent T(H)1 response. IL-12-assisted immunization provides a model in which both the generation and effector mechanisms of anti-bacterial antigen-specific CD4(+) effector cells can be analyzed.

Adjuvants, Immunologic↗

PubMed1986

Comparison of local and systemic immunity after intratracheal, intraperitoneal, and intravenous immunization of mice exposed to either aerosolized or ingested lead.

The humoral immunity of newborn mice exposed for 28 days to 2.5 mg/m3 aerosolized Pb(NO3)2 (Pb28-aero) or of 2-week-old mice similarly exposed for 14 days (Pb14-aero) was compared with that of both 2-week-old mice given 125 micrograms Pb(NO3)2/day by gastric intubation for 14 days (Pb14-oral) and of 4-week-old nonexposed controls. Mice from each group were immunized with 10(8) sheep red blood cells by intravenous (i.v.), intraperitoneal (ip), or intratracheal (it) routes of immunization. Immunity was assessed by both hemagglutination and the enumeration of antibody-forming cells from the spleen and thoracic lymph nodes. All treatment groups had decreased thymus/body weight and spleen/body weight ratios whereas only Pbaero groups had enlarged livers. The most significant immunosuppression occurred in the ip-immunized Pb28-aero group. A significant suppression of humoral immunity was also observed in thoracic lymph node samples from Pbaero groups immunized it or iv. There was no apparent immunosuppression in any treatment group after iv immunization. These results indicate that aerosolized lead is more immunosuppressive than equivalent amounts of ingested lead. This is most likely due to the greater absorption of inhaled lead and the subsequent cytotoxicity of lead for cells in the draining lymph nodes.

Animals↗

PubMed2003

DNA immunization via intramuscular and intradermal routes using a gene gun provides different magnitudes and durations on immune response.

We investigated the antibody (Ab) and cytotoxic T lymphocyte (CTL) responses to gene gun (GG)-mediated DNA immunization via the intramuscular (i.m.) and intradermal (i.d.) routes. BALB/c mice were immunized five times at weekly intervals with plasmid DNA encoding enhanced green fluorescent protein (EGFP). EGFP production was rapidly detected in the target tissues after injection via either delivery route. There were significant differences in the magnitude and duration of the Ab and CTL responses according to the route employed. Intradermal injection elicited higher Ab and CTL responses to EGFP than i.m. injection 1 week after the last immunization. However, both immune responses were reduced rapidly 5 weeks after the last immunization via i.d. injection. In contrast, in mice injected via the i.m. routes, Ab and CTL responses 5 weeks after the last immunization remained at levels similar to those detected after 1 week. All mice generated a predominantly IgG1 Ab response via either route. These findings suggest that a combination of these two routes of DNA immunization would provide optimal conditions for induction of a broad immune response, and this information is expected to be very important for future applications of DNA vaccination.

Animals↗