Showing papers on "Viral Vaccine published in 1993"

Heterologous protection against influenza by injection of DNA encoding a viral protein

Abstract: Cytotoxic T lymphocytes (CTLs) specific for conserved viral antigens can respond to different strains of virus, in contrast to antibodies, which are generally strain-specific. The generation of such CTLs in vivo usually requires endogenous expression of the antigen, as occurs in the case of virus infection. To generate a viral antigen for presentation to the immune system without the limitations of direct peptide delivery or viral vectors, plasmid DNA encoding influenza A nucleoprotein was injected into the quadriceps of BALB/c mice. This resulted in the generation of nucleoprotein-specific CTLs and protection from a subsequent challenge with a heterologous strain of influenza A virus, as measured by decreased viral lung titers, inhibition of mass loss, and increased survival.

Rotavirus vaccine administered parenterally induces protective immunity

Abstract: We performed experiments to determine whether parenteral immunization with SA11 rotavirus can induce active protective immunity in a rabbit model of rotavirus infection. After one or two intramuscular injections of 1 ml of live or formalin-inactivated SA11 virus, we evaluated the mucosal and serologic immune response and protection from challenge with a high dose of live, virulent rabbit (Ala) rotavirus. Inactivated SA11 virus preparations, evaluated by enzyme-linked immunosorbent assay (ELISA) with a panel of VP4- and VP7-specific neutralizing and nonneutralizing monoclonal antibodies, did not show a loss of epitopes from the inactivation procedure compared with live virus. Administration of two doses of vaccine, one at zero days postvaccination (DPV) and a booster shot at 49 DPV, followed by challenge at 71 DPV with 3.5 x 10(5) PFU of Ala virus resulted in protection from challenge. None of the two-dose virus-vaccinated rabbits shed virus after challenge, while virus shedding was detected in all control rabbits (P = 0.001, Fisher's exact two-tailed test). Differences in total serum immunoglobulin (Ig) antirotavirus ELISA titers (P < 0.05, Wilcoxon's rank sum test) were observed between groups vaccinated with virus in aluminum phosphate or Freund's adjuvant but not between groups vaccinated with live or inactivated virus in either adjuvant. All rabbits given two doses of vaccine had detectable antirotavirus intestinal antibody of the IgG, but not IgA, isotype. After challenge, fourfold or greater increases in intestinal IgG antibody responses were observed in three rabbits, whereas all controls and all but one virus-vaccinated rabbit had an intestinal IgA antibody response. In contrast, vaccination of rabbits with one dose of SA11 followed by challenge at 21 DPV did not protect from challenge; no difference in the mean number of days of virus shedding between any of the vaccinated groups and controls was observed. A serologic, but not a mucosal, antibody response was observed after the one-dose vaccination regimen. Differences in serologic antibody titers were not observed between any of the one-dose virus-vaccinated groups. These data indicate that parenteral vaccination with two, but not one, doses of rotavirus in either Freund's adjuvant or aluminum phosphate can induce active protection from challenge.(ABSTRACT TRUNCATED AT 400 WORDS)

A Human Respiratory Syncytial Virus (RSV) Primate Model of Enhanced Pulmonary Pathology Induced with a Formalin-Inactivated RSV Vaccine but Not a Recombinant FG Subunit Vaccine

Abstract: Human respiratory syncytial virus (RSV) is the leading cause of severe bronchiolitis and pneumonia in infants. RSV vaccine development has been stifled for the past 23 years because infants vaccinated with formalin-inactivated (FI) RSV have experienced exacerbated disease upon RSV infection. This exacerbated disease phenomenon is poorly understood, in part because of the lack of a primate model that exhibits a similar exacerbated disease state. Vaccination of African green monkeys with either FI RSV or a genetically engineered subunit vaccine termed FG glycoprotein reduced replication of challenge virus. However, only vaccination with FI RSV induced an enhanced pulmonary pathologic response to RSV infection. Pulmonary inflammatory scores in the FG glycoprotein-vaccinated monkeys were no greater than in monkeys vaccinated with adjuvant alone. This is the first demonstration of RSV vaccine-induced enhanced pathology in a primate and illustrates that a subunit vaccine has the potential of circumventing this exacerbated disease phenomenon.

Vaccination to prevent persistent viral infection.

Abstract: Persistent virus infections are increasingly being recognized as a significant cause of human morbidity and mortality. To establish persistence, a virus must establish infection and evade eradication by the host immune response, in particular by cytotoxic T lymphocytes (CTL). We have studied a virus that establishes persistence in part by suppressing the CTL response of the infected host. The virus persists in many cell types, including lymphocytes and macrophages. We show that prior immunization with a vaccine designed to induce CTL (in the absence of antiviral antibody) confers complete protection against subsequent establishment of persistence in all tissues analyzed. The vaccine can be designed to express as few as 10 amino acids of a viral protein that comprise the CTL epitope. Further, two CTL epitopes for two discrete MHC haplotypes can be successfully used in a single vaccine that protects both strains of mice. Hence, a "string of CTL epitopes" (beads) concept for vaccination is feasible. Finally, the CTL vaccine provided protection against the establishment of persistence by an immunosuppressive virus. Images

Bovine herpesvirus-1 vaccines.

Abstract: Vaccination has been important in controlling a wide variety of viral and bacterial infections of man and animals. Vaccines to herpesvirus infection of cattle are no exception. The present review describes the different types of conventional vaccines that have been used to date and furthermore describes the novel approaches which are presently being implemented to develop more effective vaccines. These include subunit vaccines as well as genetically engineered modified live deletion mutants. Both these novel vaccine approaches appear to be more efficacious than conventional vaccines. Furthermore, these vaccines provide an additional dimension for control and eradication of infection by providing an opportunity to develop companion diagnostic tests to differentiate infected animals from vaccinated animals. This review summarizes these developments as well as present knowledge regarding the important host defence mechanisms required for preventing infection and aiding recovery from infection.

Reactogenicity and immunogenicity of a high-titer rhesus rotavirus-based quadrivalent rotavirus vaccine.

Abstract: We evaluated the reactogenicity and antigenicity of a quadrivalent rotavirus vaccine composed of serotype 3 rhesus rotavirus (RRV) and three single-gene-substitution reassortants of RRV and human strain D (D x RRV, serotype 1), DS1 (DS1 x RRV, serotype 2), or ST3 (ST3 x RRV, serotype 4) in a double-masked study with 302 infants in Caracas, Venezuela. Three doses of the quadrivalent vaccine composed of either 10(5) PFU (low titer) or 10(6) PFU (high titer) of each component were administered to 99 and 101 infants, respectively, at 4-week intervals starting at the second month of age; 102 infants received a placebo. Postvaccination reactions were monitored by home visits every other day during the week postvaccination. The vaccine was associated with the occurrence of mild, short-lived febrile episodes in 26 and 23% of the recipients after the first doses of high- or low-titer vaccine, respectively, in comparison with 13% of the infants receiving the placebo. Febrile reactions occurred less frequently in vaccinees after the second or third dose than after the initial dose. The vaccine was not significantly associated with diarrhea or any additional symptom or sign. Serum specimens obtained shortly before the first, 4 weeks after the first, and 4 weeks after the third dose of vaccine or placebo were tested by an immunoglobulin A enzyme-linked immunosorbent assay and by neutralization assays. Seroresponses occurred significantly more often after 3 doses than after a single dose of either vaccine. Immunoglobulin A responses were observed in 80 and 79% of the infants after 3 doses of high- or low-titer vaccine, respectively. Most of the infants tested developed a neutralization response to RRV after 3 doses of the high- (90%) or low-(88%) titer vaccine. Neutralization response rates to human rotavirus serotypes 1 to 4 after 3 doses were similar in both vaccine and 87 of 90 receiving the high-titer vaccine developed seroresponses, as detected by any of the assays employed. The study indicates that 3 doses of quadrivalent vaccine at a titer of 10(6) PFU of each component offered no advantage over the lower-titer preparation for use in efficacy trials.

Recombinant fowlpox virus vaccines for poultry

Abstract: The intensive poultry industries rely heavily upon the use of vaccines for disease control. Viral vector based vaccines offer new avenues for the development of vaccines for effective disease control in poultry. Techniques developed for the construction of recombinant vaccinia viruses have been readily adapted to the construction of recombinant viruses based on fowlpox virus (rFPV). The ability to insert several genes into the large genome of fowlpox may enable the development of multivalent vaccines and vaccines incorporating immune response modifiers such as lymphokines. Newcastle disease, avian influenza, infectious bursal disease and Marek's disease antigens expressed by rFPV have been shown to be effective vaccines in poultry. None appear, however, to provide a substantial improvement in vaccine efficacy. Recombinant FPV will be a valuable adjunct to conventional vaccines currently in widespread use. Whether rFPV or other vector based vaccines can circumvent the problems of vaccination in the presence of high maternally derived antibodies is yet to be resolved. The observation that avipoxvirus recombinants may be suitable for the vaccination of non-avian species provides an added dimension to vaccines based on FPV or other avipoxviruses. Recombinant FPV will find a useful role in poultry disease control when used in conjunction with conventional vaccines.

Is the cold chain for vaccines maintained in general practice

Abstract: OBJECTIVE--To investigate the cold chain for vaccines and compliance with the local code of practice for storage. DESIGN--In a random sample of general practices orders for live vaccines (oral polio and measles, mumps, and rubella) were accompanied by a cold chain monitor which was activated on leaving the supplying pharmacy. The monitors were read at specified intervals and when all vaccines in the order had been used. Structured interview was used to check compliance with the local code of practice on storage. SETTING--West Berkshire and Aylesbury Vale district health authorities. SUBJECTS--16 (25%) general practices in West Berkshire, and 13 (50%) in Aylesbury Vale. MAIN OUTCOME MEASURES--Compliance with code of practice. Changes in the cold chain monitor. RESULTS--For six key requirements within the code of practice compliance varied from 70% to 0%. Only 16 of 29 practices had a named person responsible for vaccine storage and only four were aware of the local code of practice. Vaccine was stored for longer and more breaks in the cold chain occurred in West Berkshire than in Aylesbury Vale. The potency of some vaccines in 10 of 26 orders became suspect before use. CONCLUSIONS--Knowledge of appropriate management of the cold chain in two districts was poor. Breaks in the chain were more frequent and compromised potency more likely when vaccine had been stored for more than eight weeks. Problems in maintaining the cold chain indicate the need for continuing audit, which should become a prerequisite for payments to general practitioners for immunisation.

Anti-viral vaccines expressed in plants

Abstract: The anti-viral vaccine of the present invention is produced in transgenic plants and then administered through standard vaccine introduction method or through the consumption of the edible portion of those plants A DNA sequence encoding for the expression of a surface antigen of a viral pathogen is isolated and ligated to a promoter which can regulate the production of the surface antigen in a transgenic plant This gene is then transferred to plant cells using a procedure that results in its integration into the plant genome, such as through the use of an Agrobacterium tumenfaciens plasmid vector system Preferably, the foreign gene is expressed in an portion of the plant that is edible by humans or animals In a preferred procedure, the vaccine is administered through the consumption of the edible plant as food, preferably in the form of a fruit or vegetable juice which can be taken orally

Recombinant Vaccinia Virus Expressing the PR/8 Influenza Hemagglutinin Gene Overcomes the Impaired Immune Response and Increased Susceptibility of Old Mice to Influenza Infection

Abstract: Elderly humans have increased morbidity and mortality after viral influenza despite immunization. A mouse model of influenza infection was used to search for a more effective way to induce immunity to influenza. Old (18 months) BALB/c mice were more susceptible to influenza pneumonia than young (2 months) BALB/c mice after intranasal challenge with PR/8 influenza virus despite prior immunization with influenza virus. The decreased resistance to live influenza virus challenge was associated with an impaired generation of anti-hemagglutinin antibody and cytotoxic T lymphocytes in old mice. In contrast, immunization of old mice with a recombinant vaccinia virus expressing the PR/8 influenza hemagglutinin gene protected them from intranasal challenge with live influenza virus and generated high levels of anti-PR/8 influenza virus hemagglutinin antibody and PR/8-specific cytotoxic T cells. Recombinant vaccine overcame the age-associated immune defect that follows the administration of conventional viral vaccine.

Process for attenuated varicella zoster virus vaccine production

Abstract: A live, attenuated varicella zoster virus vaccine is produced with enhanced yield of VZV. The new process makes mass production of a live VZV vaccine more practical. In addition, optimized monolayer cell culture conditions provide a process for maximizing monolayer cell density which is useful for enhancing viral vaccine production. According to this process, cell densities approaching 500,000 cells/cm2 are routinely achieved in conventional culture vessels.

Vaccines for veterinary applications

Abstract: Recent advances in veterinary immunology, including mucosal immunity subunit vaccines and vectors enteric vaccines for farm animals respiratory vaccines for farm animals equine viral vaccines novel viral vaccines for small animals vaccines for poultry vaccines for fish exotic viral vaccines anti-parasite vaccines adjuvants and carriers registration and regulation EC registration and regulation US.

Development of a novel subunit vaccine that protects cotton rats against both human respiratory syncytial virus and human parainfluenza virus type 3

Abstract: A cotton rat model of experimental human respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (PIV-3) infection was used to examine the efficacy of FRHNP, a novel chimeric glycoprotein which contains the extracellular regions of the fusion glycoprotein of RSV and the attachment glycoprotein of PIV-3, as a single subunit vaccine against these two viruses. This work was prompted by previous cotton rat studies that demonstrated that the major protective antigens of the two viruses were these glycoproteins. FRHNP was expressed in insect cells using a recombinant baculovirus. Vaccination with FRHNP resulted in induction of both RSV and PIV-3 neutralizing antibody and doses of 200 ng completely protected rats from either RSV or PIV-3 challenge. These results demonstrate that in the cotton rat animal model a single chimeric glycoprotein can be an effective vaccine against both RSV and PIV-3.

Whole inactivated SIV vaccine grown on human cells fails to protect against homologous SIV grown on simian cells.

Abstract: Several groups have reported protection against experimental SIV infection in macaques immunized with a whole inactivated virus vaccine. The aim of the current study was to investigate whether five macaques vaccinated with whole inactivated SIV and previously shown to be protected against challenge with two divergent strains of SIV grown on human cells could resist challenge with a subsequent homologous SIV grown on macaque cells. We show here that this same vaccine did not protect when the challenge virus was grown on primary cells of monkey origin.

Respiratory syncytial virus vaccines: can we improve on nature?

Abstract: Both inactivated and live RSV candidate vaccines will continue to be tested in infants and young children. Sequential vaccination, with a first dose of live attenuated vaccine followed by boosting with intramuscular subunit vaccines, also is an option. We are encouraged by the fact that influenza subunit and cold-adapted live vaccines are both safe and immunogenic in infants and children of the same age group. Testing of RSV vaccines must proceed at a slower pace because of the phenomenon of vaccine-induced enhanced disease. Curiously, this phenomenon of disease enhancement has not been demonstrated in the case of inactivated influenza or parainfluenza virus vaccines. Another important step in the development of RSV vaccines is to determine a target population. Clearly, children with underlying cardiac or pulmonary disease would benefit from an RSV vaccine. It can be expected that 1% of all infants in the general population will be hospitalized for RSV infection during their first year of life. These infants also would appear to be good candidates for an RSV vaccine, but it is unclear how they would be identified before infection occurs. Immunization of the entire population of infants to protect these 1% would be feasible only if the vaccine were inexpensive and easily administered.

Reaction rate in cats vaccinated with a new controlled-titer feline panleukopenia-rhinotracheitis-calicivirus-Chlamydia psittaci vaccine.

Abstract: The safety profile of a new controlled-titer feline panleukopenia-rhinotracheitis-calicivirus-Chlamydia psittaci vaccine was compared to that of a currently-marketed vaccine. Of particular interest were delayed reactions (previously unreported in the literature in felines) occurring 7 to 21 days after vaccination, and the effect of concurrent vaccinations and cat age on the delayed reaction rate. Nineteen hundred twenty-four doses of the new vaccine and 364 doses of the comparison vaccine were administered in 42 participating veterinary practices. The postvaccination evaluation period was 21 days. Reactions (anaphylaxis, short- and long-term lethargy, inappetence, pain, upper respiratory inflammation, delayed fever, anorexia, and miscellaneous events) were reported in 3.33% of cats receiving the controlled-titer vaccine and in 3.02% of cats receiving the comparison vaccine. The difference was not statistically significant (P = 0.45). Reaction rate of the controlled-titer vaccine and that of the vaccine currently accepted by veterinarians appear to be equivalent.

Field evaluation of the efficacy of Romovac 50, a new inactivated, adjuvanted bovine rotavirus vaccine.

Abstract: An inactivated bovine rotavirus vaccine, prepared with an adjuvant which gives a water-in-oil emulsion (Montanide ISA 50, adjuvant) was used in field trials for prevention of calf neonatal diarrhoea. The vaccine, which was designated as Romovac 50, when injected into cows in their last month of pregnancy, proved to be as effective as the traditional vaccine prepared with Freund's incomplete adjuvant. Thus, the incidence of the naturally occurring neonatal diarrhoea was significantly reduced in calves which were fed mammary secretion from their vaccinated dams, compared to the calves delivered from the unvaccinated cows. Romovac 50 also has the advantages over the traditional Freund's adjuvanted vaccine in that it is less viscous and thus more readily injected and less irritant to tissues.

Protection against bovine leukemia virus infection by use of inactivated vaccines in cattle.

Abstract: The protective effects of vaccines made from the viral materials of LK15 cell line (LK15 vaccine) or bat lung cell line (Bat2cl1; Bat vaccine) infected with bovine leukemia virus (BLV) were examined in cattle. Twelve cattle were vaccinated twice at 4-week interval then challenged 4 weeks after the second inoculation. Nine cattle vaccinated with the LK15 vaccine produced antibody to BLV-specific glycoprotein (gp), and the titers ranged from 1:16 to 1:64 by the agar gel immunodiffusion test. Four cattle challenged with 100 microliters (70 to 100 syncytia) of cow blood persistently infected with BLV were protected from infection. However, of the remaining 5 cattle challenged with 500 microliters of infected blood, only 2 were protected. Of the three cattle vaccinated with the Bat vaccine, gp antibody titers ranged from 1:8 to 1:64. Two of them were protected against the challenge with 100 microliters of infected blood. Two cattle protected against the challenge were rechallenged 32 weeks after the first vaccination and not protected. On the other hand, 2 animals protected against the challenge were revaccinated with the LK15 vaccine 32 weeks after the first vaccination. They protected against rechallenge. The results show that all cattle which had gp antibody titers of 1:16 or above were protective against challenge with 100 microliters of the infected blood.

Evaluation of Live Attenuated Cold-Adapted Influenza B/Yamagataj16/88 Reassortant Virus Vaccine in Healthy Adults

Abstract: The safety and immunogenicity of a new cold-adapted reassortant influenza B/Yamagata/10/88 virus vaccine was evaluated in healthy young adults with low levels of preinoculation serum antibody to the vaccine virus, and symptoms and viral shedding after vaccination were compared with those following administration of the homologous B/Yamagata/88 wild-type virus. Administration of the cold-adapted virus was well tolerated and resulted in a significantly lower frequency of respiratory symptoms and viral shedding than did the wild-type virus. Twelve of 14 subjects who received the cold-adapted virus had an antibody response to the vaccine virus following vaccination. These data suggest that the B/Yamagata/88 virus is safe and immunogenic in seronegative adults and support the concept that the attenuation phenotype can be transferred reliably and reproducibly to successive new influenza B wild-type viruses along with the six internal gene segments of the cold-adapted influenza B/Ann Arbor/1/66 master vaccine virus.

Water and viral hepatitis

Abstract: The main agents responsible for acute viral hepatitis throughout the world are the hepatitis A virus (HAV) and the hepatitis E virus (HEV). Both are transmitted by fecal-oral route and can provoke large epidemics, HAV in developed countries and HEV in developing countries. Water is a major vehicle of spread. However, two different epidemiological patterns have to be distinguished: level of HAV excretion is short but high. Because of its resistance to physical and chemical agents, HAV remains infectious for a long time under environmental conditions. Progress in hygiene have nearly stopped the circulation of HAV in industrialized countries, making populations more susceptible to the infection and increasing the epidemic risk. Conventional measures sometimes fail to prevent HAV infections. Vaccine is currently the best way for hepatitis A prophylaxis; HEV is excreted briefly and at low concentrations. Viral particles are fragile in vitro and their viability in environment is not yet understood. Epidemics mainly occur in countries with poor sanitary conditions, resulting from heavy water pollutions. High case-fatality rates are observed, especially among pregnant women. The control of enterically transmitted viral hepatitis remains a major public health challenge. Virological surveillance of waste water could improve strategies based on hygiene, sanitation and supply of drinking water.