Role of the Abcg2 transporter in plasma levels and tissue accumulation of the anti-inflammatory tolfenamic acid in mice.

The Breast Cancer Resistance Protein (BCRP/ABCG2) is an ATP-binding cassette efflux transporter that is expressed in the apical membrane of cells from relevant tissues involved in drug pharmacokinetics such as liver, intestine, kidney, testis, brain and mammary gland, among others. Tolfenamic acid is an anti-inflammatory drug used as an analgesic and antipyretic in humans and animals. Recently, tolfenamic acid has been repurposed as an antitumoral drug and for use in chronic human diseases such as Alzheimer. The aim of this work was to study whether tolfenamic acid is an in vitro Abcg2 substrate, and to investigate the potential role of Abcg2 in plasma exposure, secretion into milk and tissue accumulation of this drug. Using in vitro transepithelial assays with cells transduced with Abcg2, we showed that tolfenamic acid is an in vitro substrate of Abcg2. The in vivo effect of this transporter was tested using wild-type and Abcg2-/- mice, showing that after oral and intravenous administration of tolfenamic acid, its area under the plasma concentration-time curve in Abcg2-/- mice was between 1.7 and 1.8-fold higher compared to wild-type mice. Abcg2-/- mice also showed higher liver and testis accumulation of tolfenamic acid after intravenous administration. In this study, we demonstrate that tolfenamic acid is transported in vitro by Abcg2 and that its plasma levels as well as its tissue distribution are affected by Abcg2, with potential pharmacological and toxicological consequences.

Live Attenuated Tularemia Vaccines for Protection Against Respiratory Challenge With Virulent F. tularensis subsp. tularensis.

Francisella tularensis is the causative agent of tularemia and a Tier I bioterrorism agent. In the 1900s, several vaccines were developed against tularemia including the killed "Foshay" vaccine, subunit vaccines comprising F. tularensis protein(s) or lipoproteins(s) in an adjuvant formulation, and the F. tularensis Live Vaccine Strain (LVS); none were licensed in the U.S.A. or European Union. The LVS vaccine retains toxicity in humans and animals-especially mice-but has demonstrated efficacy in humans, and thus serves as the current gold standard for vaccine efficacy studies. The U.S.A. 2001 anthrax bioterrorism attack spawned renewed interest in vaccines against potential biowarfare agents including F. tularensis. Since live attenuated-but not killed or subunit-vaccines have shown promising efficacy and since vaccine efficacy against respiratory challenge with less virulent subspecies holarctica or F. novicida, or against non-respiratory challenge with virulent subsp. tularensis (Type A) does not reliably predict vaccine efficacy against respiratory challenge with virulent subsp. tularensis, the route of transmission and species of greatest concern in a bioterrorist attack, in this review, we focus on live attenuated tularemia vaccine candidates tested against respiratory challenge with virulent Type A strains, including homologous vaccines derived from mutants of subsp. holarctica, F. novicida, and subsp. tularensis, and heterologous vaccines developed using viral or bacterial vectors to express F. tularensis immunoprotective antigens. We compare the virulence and efficacy of these vaccine candidates with that of LVS and discuss factors that can significantly impact the development and evaluation of live attenuated tularemia vaccines. Several vaccines meet what we would consider the minimum criteria for vaccines to go forward into clinical development-safety greater than LVS and efficacy at least as great as LVS, and of these, several meet the higher standard of having efficacy ≥LVS in the demanding mouse model of tularemia. These latter include LVS with deletions in purMCD, sodBFt , capB or wzy; LVS ΔcapB that also overexpresses Type VI Secretion System (T6SS) proteins; FSC200 with a deletion in clpB; the single deletional purMCD mutant of F. tularensis SCHU S4, and a heterologous prime-boost vaccine comprising LVS ΔcapB and Listeria monocytogenes expressing T6SS proteins.

Vibrio anguillarum bacterin uptake via the gills of Japanese flounder and subsequent immune responses.

The mucosal surfaces of fish allow for the introduction of foreign substances, including antigens, from the surrounding environment. In this study, uptake of Vibrio anguillarum J-O-3 serotype bacterin by Japanese flounder, and the subsequent immune responses were investigated. Immunohistochemistry revealed that the bacterin was taken up through the epithelial cells of gills. The transcription levels of inflammatory cytokines such as interleukin (IL)-1ß, IL-6 and tumor necrosis factor α were significantly up-regulated in the gills at 3 days following exposure to the bacterin. There was also a corresponding increase in IL-8 receptor, CD4-1, CD4-2 and CD8α transcript levels in the gills. Our findings suggest that the gills play a major role in the uptake of V. anguillarum bacterin and induction of inflammation, which results in an activation of the adaptive immune response in teleost fish.

Chlamydia trachomatis recombinant MOMP encapsulated in PLGA nanoparticles triggers primarily T helper 1 cellular and antibody immune responses in mice: a desirable candidate nanovaccine.

We recently demonstrated by in vitro experiments that PLGA (poly D, L-lactide-co-glycolide) potentiates T helper 1 (Th1) immune responses induced by a peptide derived from the recombinant major outer membrane protein (rMOMP) of Chlamydia trachomatis, and may be a promising vaccine delivery system. Herein we evaluated the immune-potentiating potential of PLGA by encapsulating the full-length rMOMP (PLGA-rMOMP), characterizing it in vitro, and investigating its immunogenicity in vivo. Our hypothesis was that PLGA-rMOMP triggers Th1 immune responses in mice, which are desirable prerequisites for a C. trachomatis candidate nanovaccine. Physical-structural characterizations of PLGA-rMOMP revealed its size (approximately 272 nm), zeta potential (-14.30 mV), apparent spherical smooth morphology, and continuous slow release pattern. PLGA potentiated the ability of encapsulated rMOMP to trigger production of cytokines and chemokines by mouse J774 macrophages. Flow cytometric analyses revealed that spleen cells from BALB/c mice immunized with PLGA-rMOMP had elevated numbers of CD4+ and CD8+ T cell subsets, and secreted more rMOMP-specific interferon-gamma (Th1) and interleukin (IL)-12p40 (Th1/Th17) than IL-4 and IL-10 (Th2) cytokines. PLGA-rMOMP-immunized mice produced higher serum immunoglobulin (Ig)G and IgG2a (Th1) than IgG1 (Th2) rMOMP-specific antibodies. Notably, sera from PLGA-rMOMP-immunized mice had a 64-fold higher Th1 than Th2 antibody titer, whereas mice immunized with rMOMP in Freund's adjuvant had only a four-fold higher Th1 than Th2 antibody titer, suggesting primarily induction of a Th1 antibody response in PLGA-rMOMP-immunized mice. Our data underscore PLGA as an effective delivery system for a C. trachomatis vaccine. The capacity of PLGA-rMOMP to trigger primarily Th1 immune responses in mice promotes it as a highly desirable candidate nanovaccine against C. trachomatis.

Engineered hepatitis B virus surface antigen L protein particles for in vivo active targeting of splenic dendritic cells.

Dendritic cells (DCs) are key regulators of adaptive T-cell responses. By capturing exogenous antigens and presenting antigen-derived peptides via major histocompatibility complex molecules to naïve T cells, DCs induce antigen-specific immune responses in vivo. In order to induce effective host immune responses, active delivery of exogenous antigens to DCs is considered important for future vaccine development. We recently generated bionanocapsules (BNCs) consisting of hepatitis B virus surface antigens that mediate stringent in vivo cell targeting and efficient endosomal escape, and after the fusion with liposomes (LP) containing therapeutic materials, the BNC-LP complexes deliver them to human liver-derived tissues in vivo. BNCs were further modified to present the immunoglobulin G (IgG) Fc-interacting domain (Z domain) derived from Staphylococcus aureus protein A in tandem. When mixed with IgGs, modified BNCs (ZZ-BNCs) displayed the IgG Fv regions outwardly for efficient binding to antigens in an oriented-immobilization manner. Due to the affinity of the displayed IgGs, the IgG-ZZ-BNC complexes accumulated in specific cells and tissues in vitro and in vivo. After mixing ZZ-BNCs with antibodies against DCs, we used immunocytochemistry to examine which antibodies delivered ZZ-BNCs to mouse splenic DCs following intravenous injection of the ZZ-BNCs. ZZ-BNCs displaying anti-CD11c monoclonal antibodies (α-CD11c-ZZ-BNCs) were found to accumulate with approximately 62% of splenic DCs, and reside within some of them. After the fusion with liposomes containing antigens, the α-CD11c-ZZ-BNCs could elicit the respective antibodies more efficiently than other nontargeting control vaccines, suggesting that this DC-specific nanocarrier is promising for future vaccines.

Combining vitamin A and vaccines: convenience or conflict?

The present thesis is based on 11 papers from 1995-2010. The studies have mainly taken place at the Bandim Health Project in Guinea-Bissau, West Africa, but a reanalysis of a randomised trial from Ghana is also included. My research has explored the consequences of combining high-dose vitamin A supplementation and childhood vaccines. Vitamin A deficiency is associated with increased mortality. To protect against the consequences of vitamin A deficiency the World Health Organization recommends that high-dose vitamin A supplements be given together with routine vaccines to children between 6 months and 5 years of age in more than 100 low-income countries. The recommendation is based on logistical considerations. The consequences of combining vitamin A and vaccines were not investigated in randomised trials prior to the implementation of this policy - it was assumed that the interventions were independent. My first project aimed to study the effect on the immune response to measles of providing vitamin A together with measles vaccine. We found that the two interventions were not independent. Vitamin A enhanced the antibody response to measles vaccine given at 9 months of age significantly, especially in boys. The effects were sustained over time; the children who had received vitamin A with their measles vaccine were more protected against measles at 6-8 years of age. Though vitamin A supplementation had a beneficial effect on the immune response to measles vaccine, it intrigued me that the effect of vitamin A supplementation on overall mortality was not always beneficial. While vitamin A was beneficial when given after 6 months of age, and two studies had shown a beneficial effect when given at birth, all studies testing the effect between 1-5 months of age had found no effect. These time windows are dominated by three different childhood vaccines: BCG vaccine given at birth, diphtheria-tetanus-pertussis (DTP) vaccine given between 1-5 months of age, and measles vaccine given at 9 months of age. These vaccines have been shown to have strong effects on mortality from infectious diseases in general, so-called non-specific effects. The live BCG and measles vaccine protects against more mortality than can be ascribed to the prevention of tuberculosis and measles, respectively. The inactivated DTP vaccine worryingly has been associated with increased mortality from other infectious diseases. Both positive and negative effects are strongest for girls. I proposed the hypothesis that vitamin A amplifies not only the specific vaccine effects, as we saw for measles vaccine, but also the non-specific effects of vaccines on mortality from other infectious diseases. According to my hypothesis, vitamin A would enhance the non-specific beneficial effects on mortality of BCG and measles vaccine, but also the negative effects of DTP vaccine. Hence, the hypothesis offered an explanation for the mortality-age pattern after vitamin A supplementation. Since it was formulated, I have aimed to test this hypothesis. Since it is associated with ethical problems to randomise children above 6 months of age to vitamin A supplementation, and to randomise children in general to recommended vaccines, we have had to be pragmatic when designing the trials. Hence, our studies have taken many different forms. We conducted an observational study during a vitamin A campaign in which missing vaccines were also provided, and a randomised trial testing the effect of two different doses of vitamin A during another campaign; we tested the effect of providing vitamin A with BCG at birth in two randomised trials, and we reanalysed data from one of the original randomised trials of vitamin A supplementation from the perspective of vaccination status. In all studies the main outcome was mortality. The results document that vitamin A supplements do more than protect against vitamin A deficiency. They support the hypothesis that vitamin A supplements interact with vaccines with important consequences for mortality. First, a smaller dose of vitamin A was more beneficial than a larger dose for girls. Second, the effect of vitamin A given with DTP vaccine was significantly different from the effect of vitamin A given with measles vaccine, and children, who received vitamin A with DTP vaccine, had higher mortality than children, who had received vitamin A alone, or who did not receive anything. Third, vitamin A given with BCG at birth interacted negatively with subsequent DTP vaccines in girls. Fourth, the effect of vitamin A to older children in Ghana depended on vaccination status, being beneficial in boys, but harmful in girls who received DTP vaccine during follow-up. The results also show that boys and girls respond differently to vitamin A and vaccines. It is a common assumption within public health in low-income countries that interventions can be combined without producing unexpected consequences. The work presented in this thesis confronts this assumption; the results show that vitamin A and vaccines should be seen not only as specific interventions with specific and independent effects, but as immuno-modulators, which can interact with important consequences for overall mortality. Combining interventions can be convenient and lead to synergistic health benefits, but we documented several examples, where it also leads to unexpectedly increased mortality. Thus, to optimise the child health intervention policy in low-income countries a shift in paradigm is needed. Health interventions should no longer be seen as merely specific and independent, and the policy should probably not be the same for boys and girls. Though more complex, it is necessary to evaluate all health interventions in terms of their effect on overall mortality - and their potential interactions with other health interventions and potential sex-differential effects should always be investigated. Only in this way can we assure that the children in the poorest countries get the best possible treatment and avoid using large amounts of money and resources on interventions which may, in worst case, kill them.

In vivo molecular imaging analysis of a nasal vaccine that induces protective immunity against botulism in nonhuman primates.

Nasal administration is an effective route for a needle-free vaccine. However, nasally administered Ags have the potential to reach the CNS directly from the nasal cavity, thus raising safety concerns. In this study, we performed real-time quantitative tracking of a nasal vaccine candidate for botulism, which is a nontoxic subunit fragment of Clostridium botulinum type A neurotoxin (BoHc/A) effective in the induction of the toxin-neutralizing immune response, by using (18)F-labeled BoHc/A-positron-emission tomography, an in vivo molecular imaging method. This method provides results that are consistent with direct counting of [(18)F] radioactivity or the traditional [(111)In]-radiolabel method in dissected tissues of mice and nonhuman primates. We found no deposition of BoHc/A in the cerebrum or olfactory bulb after nasal administration of (18)F-labeled BoHc/A in both animals. We also established a real-time quantitative profile of elimination of this nasal vaccine candidate and demonstrated that it induces highly protective immunity against botulism in nonhuman primates. Our findings demonstrate the efficiency and safety of a nasal vaccine candidate against botulism in mice and nonhuman primates using in vivo molecular imaging.

Liposomes based on dimethyldioctadecylammonium promote a depot effect and enhance immunogenicity of soluble antigen.

The mechanism behind the immunostimulatory effect obtained with the cationic liposomal vaccine adjuvant DDA:TDB remains unclear. One of the proposed hypotheses is the 'depot effect' in which the liposomal carrier helps to retain the antigen at the injection site thereby increasing the time of vaccine exposure to the immune cells. In the present study we devise a method to quantify the in vivo movement of liposomes and vaccine antigen using the radioisotopes H(3) and I(125) respectively. H(3)-labeled liposomes composed of dimethyldioctadecylammonium bromide (DDA) or an 8:1 molar ratio of DDA and trehalose 6,6-dibehenate (TDB) were administered in combination with I(125)-labeled Ag85B-ESAT-6 antigen, both via intramuscular and subcutaneous injection to mice. Furthermore characterisation of the liposomal system in simulated in vivo conditions was undertaken. Our results show that this dual-labeling technique is functional and reproducible. The administration of Ag85B-ESAT-6 without a liposomal carrier leads to rapid dissemination of the antigen from the site of injection. The administration of Ag85B-ESAT-6 together with either DDA or DDA:TDB liposomes however leads to deposition of the antigen at the injection site with detectable levels still being present 14 days post injection. Neither the incorporation of TDB nor the route of injection had any significant influence on the depot effect of DDA-based liposomes. The presence of TDB in DDA liposomes improves draining of liposomes to the lymph node in addition to increasing monocyte influx to the site of injection as highlighted by the intensive blue colouring of the injection site after pontamine blue staining of phagocytic cells in vivo. Our findings provide conclusive evidence for a cationic liposome-mediated deposition of antigen at the injection site with improved monocyte infiltration.

Safety and immunogenicity of a pentavalent vaccine compared with separate administration of licensed equivalent vaccines in US infants and toddlers and persistence of antibodies before a preschool booster dose: a randomized, clinical trial.

OBJECTIVE: Our goal was to compare the safety and immunogenicity of a combination vaccine (DTaP(5)-IPV-Hib; Pentacel) with that of its separately administered, US-licensed equivalent vaccines (diphtheria, tetanus, 5-component acellular pertussis vaccine [DTaP(5); Daptacel], inactivated poliovirus vaccine [IPV; IPOL], and Haemophilus influenzae type b [Hib] vaccine [ActHIB]), when administered to infants and toddlers concomitantly with other routinely recommended vaccines and to assess antibody persistence from the fourth dose in toddlers to the fifth (preschool) DTaP(5) dose. SUBJECTS AND METHODS: In this randomized, multicenter study, 1939 healthy infants were immunized at 2, 4, and 6 months of age with 1 of 3 lots of DTaP(5) coadministered with IPV and Hib vaccines or 1 lot of DTaP(5)-IPV-Hib combination vaccine. Subsequently, 849 of these study participants were given a fourth dose of DTaP(5) and Hib vaccines or a fourth dose of DTaP(5)-IPV-Hib at 1 to 16 months of age. Safety was monitored throughout the study, and blood specimens were obtained to assess antibody responses. RESULTS: DTaP(5)-IPV-Hib elicited similar or fewer solicited injection-site and systemic reactions as compared with the separate administration of US-licensed DTaP(5), IPV, and Hib vaccines. Seroresponse and seroprotection rates elicited by DTaP(5)-IPV-Hib were noninferior to US-licensed equivalent vaccines after the infant series and after the fourth dose. Children immunized with DTaP(5)-IPV-Hib had higher antibody geometric mean concentrations to pertussis toxoid and filamentous hemagglutinin; children immunized with the separate vaccines had higher responses to pertactin. Hib antibody responses to Hib polysaccharide were nearly identical in the DTaP(5)-IPV-Hib and separate-vaccine groups. Persistence of antibodies to the fifth (preschool) dose was also similar between groups. CONCLUSIONS: DTaP(5)-IPV-Hib combination vaccine was shown to be immunogenic and well tolerated. No clinically important differences in the safety or immunologic profiles were noted for DTaP(5)-IPV-Hib versus the separately administered, US-licensed equivalent vaccines. DTaP(5)-IPV-Hib is a suitable replacement for separately administered DTaP, IPV, and Hib vaccines.

Evidence based route of administration of vaccines.

Vaccination is a proven public health initiative, however it is imperative in the context of increasing concerns about vaccine induced adverse reactions and a decreasing incidence of diseases they prevent that the optimal route for their administration is defined. Traditionally all vaccines were given by subcutaneous injection until it was recognized that adjuvanted vaccines given via this route induced an unacceptable rate of injection site reaction. Evidence-based medicine has been championed as a way of improving the quality of patient care. Application of this methodology to the route of administration of vaccines demonstrates that vaccines should be given by intramuscular injection in preference to subcutaneous injection as the intramuscular route is associated with better immune response and a lower rate of injection site reaction. The basis of this superiority is discussed.

[New routes of administration: epidermal, transcutaneous mucosal ways of vaccination]. / Nouvelles voies d'administration : vaccinations par voie épidermique, intradermique, muqueuse.

A successful vaccine triggers the interaction of various cells of the immune system as does a regular immune response. It is thus necessary to introduce the vaccine antigens into an anatomic site where they will contact immune cells. The route of administration is thus critical for the outcome of vaccination. Intramuscular or subcutaneous injections are the most popular. Antigens injected intramuscularly can form persistent precipitates that are dissolved and re-absorbed relatively slowly. If injecting antigens is a quick, easy and reproducible way to vaccination, it requires trained personnel. Alternatives exist, through non-invasive formulations which allow administration by the patient or a third party with no particular expertise. The skin, especially its epidermal layer, is an accessible and competent immune environment and an attractive target for vaccine delivery, through transcutaneous delivery or immunostimulant patches. Mucosal immunization is another strategy: its major rationale is that organisms invade the body via mucosal surfaces. Therefore, local protection at mucosal surface as well as systemic defense is beneficial. Various formulations of mucosal vaccines have been developed, such as the Sabin oral polio vaccine (OPV), rotavirus vaccines, cold-adapted influenza vaccines or vaccine against typhoid fever. Thus we are entering in an era where mucosal and transcutaneous immunisation will play an important role in disease management. However, it has not been so easy to obtain regulatory approval for mucosal or transcutaneous formulations and needle-based vaccines continue to dominate the market.

Oral immunization of Carassius auratus with modified recombinant A-layer proteins entrapped in alginate beads.

This study was focused on the utilization of a recombinant expression system to produce a unique modified subunit vaccine possessing a self-contained delivery system which could potentially improve the uptake and delivery of vaccine products as well their immunogenic potential. For this purpose the A-layer protein (At-R) associated with the fish pathogen atypical Aeromonas salmonicida was cloned and modified by the genetic fusion of the protein transduction domain (MTS) derived from Kaposi fibroblast growth factor (At-MTS). The potential for these proteins to be employed as antigens for oral immunization of goldfish was examined by encapsulation of At-R, At-MTS and the control, BSA, into biodegradable alginate gel macrospheres which were fed to goldfish in place of standard pellet fish feed. The bead physical properties were modified only in the presence of At-R and the temporal release of proteins was significantly less when At-MTS was employed. Western blot analysis of serum samples collected from fish following intubation with the recombinant proteins determined that the rate of protein uptake from the digestive tract into the blood system improved considerably when MTS was fused to At-R. Experimental fish were fed one of three protein-alginate formulae on a schedule of 3 days/week or 5 days/month for a period of 2 months. After 1 month, animals fed on the 5-day protocol demonstrated increased serum antibody titers while following an additional month of feeding this level decreased and titers were found to be higher in fish maintained on the 3-day regime. Fish fed At-MTS maintained the highest titer at the end of 2-month period. To determine whether the diminished antibody titers were a result of oral tolerance fish were injected intraperitoneally with the At-R antigen. Only experimental groups which had been fed At-R or At-MTS demonstrated increased antibody titers which paralleled a typical secondary humoral response. In spite of the presence of an increased titer to A-protein, vaccinated fish did not demonstrate resistance to infection with atypical A. salmonicida.

Oral vaccination of African catfish with Vibrio anguillarum O2: effect on antigen uptake and immune response by absorption enhancers in lag time coated pellets.

The impact on antigen uptake and antibody response by the addition of absorption enhancers to Vibrio anguillarum O2 antigen was studied in oral vaccination trials of African catfish (Clarias gariepinus). Oral vaccination was achieved by feeding lag time coated pellets. The lag time coat prevents premature release of the encapsulated vaccine in the tank, before ingestion of the pellets by the fish. To monitor the antigen uptake, a competitive ELISA was used. The antibody response was measured using an indirect ELISA. Feeding of bacterin-layered pellets without absorption enhancers resulted in a rather low antigen uptake and antibody levels. The addition of absorption enhancers such as sodium salicylate, sodium caprate and vitamin E TPGS increased the serum antigen levels and specific antibody levels in the systemic circulation. Skin mucus antibody levels were higher after oral vaccination compared to the IP and control group. The addition of absorption enhancers in the oral groups further increased the antibody levels obtained in the skin mucus.

Controlled release of Bordetella bronchiseptica dermonecrotoxin (BBD) vaccine from BBD-loaded chitosan microspheres in vitro.

Chitosan microspheres were prepared by ionic gelation process with sodium sulfate for nasal vaccine delivery. Bordetella Bronchiseptica Dermonecrotoxin (BBD) as a major virulence factor of a causative agent of atrophic rhinitis (AR) was loaded to the chitosan microspheres for vaccination. Morphology of BBD-loaded chitosan microspheres was observed as spherical shapes. The average particle sizes of the BBD-loaded chitosan microspheres were about 2.69 microm. More BBD was released with an increase of molecular weight of chitosan and with an increase of medium pH in vitro due to weaker intermolecular interaction between chitosan and BBD. Tumor necrosis factor-alpha (TNFalpha) and nitric oxide (NO) from RAW264.7 cells stimulated with BBD-loaded chitosan microspheres were gradually secreted, suggesting that released BBD from chitosan microspheres had immune stimulating activity of AR vaccine.

Responses of cattle to two dosages of Brucella abortus strain RB51: serology, clearance and efficacy.

A new brucellosis vaccine, Brucella abortus strain RB51 (SRB51), is currently recommended for use as a calfhood vaccine in the US at dosages between 1 x 10(10)and 3.4 x 10(10)colony-forming units (CFU). The purpose of the study reported here was to compare responses to minimal and maximal recommended SRB51 dosages. Eighteen heifer calves were vaccinated subcutaneously with 1.6 x 10(10)CFU of SRB51, 3.2 x 10(10)CFU of SRB51, or saline (n = 6 per treatment). The vaccine strain was recovered from the superficial cervical lymph node 14 weeks after vaccination in two of six animals that received 1.6 x 10(10)CFU SRB51, but not from any cattle vaccinated with 3.2 x 10(10)CFU SRB51. The higher SRB51 dosage stimulated greater antibody titres. Protection against abortion or infection following B. abortus strain 2308 (S2308) challenge was similar for both SRB51 dosages and greater than resistance of non-vaccinates. The vaccine strain was recovered from one heifer and her fetus at necropsy 1 week prior to estimated parturition. Data from this study suggests that SRB51 induces similar protective immunity across the recommended dosage range. The SRB51 vaccine may persist in some cattle into adulthood but the incidence and significance of this persistence remains unknown.

Oral immunization with a Streptococcal pneumoniae polysaccharide conjugate vaccine in enterocoated microparticles induces serum antibodies against type specific polysaccharides.

The authors examined the antibody responses of mice orally immunized with pneumococcal polysaccharide (type 23F) or a pneumococcal polysaccharide conjugated to the outer membrane protein complex of Neisseria meningitides (23F-OMPC). These antigens were administered either in solution or entrapped within microcapsules. Only the mice receiving the encapsulated conjugate vaccine produced significant levels of anti-polysaccharide serum antibodies. These responses, observed after a second oral immunization with the conjugate, were predominantly IgG. Thus, the conversion from a T-cell-independent to a T-cell dependent response, achieved through conjugation was maintained following oral delivery. However, no local secretory IgA anti-polysaccharide response was detected in these mice indicating that while the OMPC carrier augments orally induced IgG responses, it was insufficient for the induction of secretory IgA.

Cinética de la respuesta de anticuerpos bactericidas y de la IgG específica en individuos vacunados con VA-MENGOC-BC / Kinetics of the response of bactericidal antibodies and of the specific IgG in individuals vaccinated with VA-MENGOC-BC

Se evaluó la cinética de la respuesta de anticuerpos bactericidas frente a la cepa vacunal Cu85/83 (B:4P1.15) y de la IgG específica contra proteínas vacunales (PV) en 220 individuos vacunados con VA-MENGOC-BC, vacuna cubana contra la Neisseria meningitidis serogrupo B y C. Se realizó un análisis multivariado y los mayores incrementos de IgG anti-PV y de la actividad bactericida sérica (ABs) se observaron después de la segunda dosis vacunal, lo que sugiere la existencia de memoria inmunológica dependiente de células B como mecanismo protector

Cinética de la respuesta de anticuerpos bactericidas y de la IgG específica en individuos vacunados con VA-MENGOC-BC / Kinetics of the response of bactericidal antibodies and of the specific IgG in individuals vaccinated with VA-MENGOC-BC

Se evaluó la cinética de la respuesta de anticuerpos bactericidas frente a la cepa vacunal Cu85/83 (B:4P1.15) y de la IgG específica contra proteínas vacunales (PV) en 220 individuos vacunados con VA-MENGOC-BC, vacuna cubana contra la Neisseria meningitidis serogrupo B y C. Se realizó un análisis multivariado y los mayores incrementos de IgG anti-PV y de la actividad bactericida sérica (ABs) se observaron después de la segunda dosis vacunal, lo que sugiere la existencia de memoria inmunológica dependiente de células B como mecanismo protector(AU)

Biodistribution of the Cuban anti-meningococcal vaccine, VA-MENGOC-BC, in Balb/c mice.

VA-MENGOC-BC is the Cuban vaccine against Neisseria meningitidis BC. Its iodination and biodistribution measurement in Balb/c mice were the main goals of this study. The Chloramine-T method was effective for radiolabelling the proteoliposome, the main vaccine structure. The biodistribution demonstrated that the thyroid (50.4%), muscle (21.5%) and regional lymph nodes (20.5%) were the most radioactive organs and the kinetic of radioactivity was correlated with the primary (muscle, highest values in the first 3 days and lymph nodes, in the first 7 days) and secondary (muscle and lymph nodes, highest values in the first day) response. Early occurrence of slight radioactivity in the spleen was also observed. This was the first time that the iodination and biodistribution of this vaccine was carried out. The present study corroborated that the time selected in previous trials to obtain the lymph nodes and spleen cell, after a first (7 days) and second (3 days) dose, was actually the optimal for in vitro studies.