Showing papers on "Viral Vaccine published in 1985"

Mutagen-directed attenuation of Rift Valley fever virus as a method for vaccine development.

Abstract: Serial mutagenesis with 5-fluorouracil has been employed to derive an attenuated strain of Rift Valley fever virus for use as a live virus vaccine

Protection of cottontop tamarins against Epstein-Barr virus-induced malignant lymphoma by a prototype subunit vaccine.

Abstract: Epstein-Barr (EB) virus is one of the five herpesviruses of man. Strong links between this agent and the chain of events causing two human cancers, endemic Burkitt's lymphoma and undifferentiated nasopharyngeal carcinoma, have long been evident (reviewed in ref. 1). Because of this, and because of the very high incidence of nasopharyngeal carcinoma in certain large populations, it was suggested in 1976 that a vaccine should be developed against EB virus to prevent infection and thereby reduce tumour incidence amongst those at risk. The virus-determined membrane antigen (MA) was proposed as immunogen because it was known to elicit naturally occurring virus-neutralizing antibodies in man and because analogous antigens had been shown to act as effective experimental vaccines for preventing the herpesvirus-induced lymphomas of Marek's disease in chickens. Progress has been achieved in defining, quantifying and preparing MA molecules, and in enhancing their immunogenicity; a sensitive assay for antibodies to MA has been elaborated. Here we report that isolated cell membranes expressing MA, or purified MA glycoprotein of relative molecular mass (Mr) 340,000 (gp340), have been used to vaccinate cottontop tamarins (Saguinus oedipus oedipus), and that animals receiving either preparation were protected against the effects of a 100% tumour-inducing challenge dose of EB virus.

Herpes Simplex Virus Infection: Biology, Treatment, and Prevention

Abstract: Herpes simplex viruses cause common mucocutaneous infections, but many aspects of their epidemiology and transmission are incompletely defined. Although the incidence of oral herpes remains relatively unchanged, the incidence of genital herpes is increasing significantly. Definitive diagnosis of herpes remains dependent on virus isolation, but techniques involving direct examination of clinical specimens are increasingly sensitive and may simplify and speed diagnosis. With the advent of acyclovir, effective therapy and suppression of infection are feasible for immunodeficient and selected normal patients. Unanswered questions remain regarding the long-term safety of acyclovir and the potential for emergence of clinically significant drug resistance. No effective vaccines are yet available for herpes virus infections. Promising strategies for vaccine development include preparation of immunogenic proteins, engineering of specially attenuated live virus strains, and incorporation of selected herpes genes into live vaccinia virus vectors.

Preparation of inactivated viral vaccines

Abstract: Vaccines employing inactivated viruses having improved retention of antigenic characteristics are prepared by psoralen-inactivation of the live virus in a non-oxidizing atmosphere. By excluding oxygen and other oxidizing species from the inactivation medium, degradation of the antigen characteristics resulting from irradiation with ultraviolet light is largely prevented. The resulting inactivated viruses are employed in vaccine preparations for the inoculation of susceptible hosts to inhibit viral infection.

Chemotherapy and vaccination: a possible strategy for the control of highly virulent influenza virus.

Abstract: The influenza A virus [A/Chicken/Pennsylvania/1370/83 (H5N2)] that caused up to 80% mortality among chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. Amantadine and rimantadine administered in drinking water were efficacious both prophylactically and therapeutically. However, under conditions simulating natural transmission of virus, amantadine- and rimantadine-resistant viruses arose and were transmitted to other birds in contact with the infected chickens, causing mortality. Simultaneous administration of inactivated H5N2 vaccine and amantadine provided protection. Thus, chemotherapy may be useful in the treatment of a highly pathogenic influenza virus outbreak in humans or other animals when used in combination with vaccine.

Clinical efficacy of a herpes simplex subunit vaccine.

Abstract: A DNA-free herpes simplex type 2 subunit vaccine was administered to 18 volunteers without past evidence of herpes simplex type 1 (HSV 1) or herpes simplex type 2 (HSV 2) infection, to 44 patients with severe recurrent genital HSV 2 infection, and to 15 patients with severe oral type 1 HSV recurrences. The vaccine elicited both humoral and cell-mediated immunity in 97% of the subjects without past HSV infections and boosted significantly the cell-mediated immunity and antibody titers in almost all the patients with recurrent HSV 1 or HSV 2. The vaccine elicited particularly the production of complement-dependent cytotoxic antibodies in 96% of the patients with recurrent HSV 2 infections. This might, at least partly, explain the clinical efficacy of the vaccine. Indeed, we observed a significant decrease (t test, p less than 0.01) in the attack rate of the recurrences and also a significant shortening of the time needed to complete healing of the lesions (t test, p less than 0.01).

Newer Directions in Vaccine Development and Utilization

Abstract: The gradually evolving technology for vaccine development from Jenner to recombinant genetics has provided both solid accomplishment and possible bases for prophylactic control of essentially all the infectious diseases of humans. The present review gives a prospective view of future vaccines and the new biotechnology as illustrated mainly in the examples of vaccines for control of hepatitis and of herpesvirus infections. Although vaccines offer great benefit for human health, their use is restricted in developing countries by lack of funds and in developed countries such as the United States by failure of application, mainly in adults. Practical matters relating to vaccine use must be resolved if there is to be justification for vaccine development.

Varicella vaccine in children with chronic renal insufficiency.

Abstract: This study reports the antibody response and clinical follow-up of uraemic children awaiting kidney transplantation after administration of the Oka-strain varicella vaccine (Varilirix). Seroconversion was observed in 20 out of 23 patients found to be seronegative when tested by the fluorescent antibody to membrane antigen technique, and an antibody booster response was observed in 41 out of 47 seropositive patients. Mild clinical varicella occurred in 5 vaccinated patients and herpes zoster in 3 initially seropositive ones. Nevertheless, a dramatic decrease in the incidence of both varicella and herpes zoster was observed in a series of 330 consecutive transplantations after the introduction of the varicella vaccine.

Immune responses of cattle and mice to the G glycoprotein of vesicular stomatitis virus.

Abstract: A subunit vaccine for vesicular stomatitis was developed from a purified vesicular stomatitis virus preparation by selectively removing the immunogenic G glycoprotein of the virus with the dialyzable, nonionic detergent, β-D-octylglucoside. Cattle immunized intramuscularly with a single dose of 112 µg of G glycoprotein preparation in complete Freund’s adjuvant did not develop vesicular disease following challenge by intralingual inoculation of 400 times the infectious dose of the virus. Similarly, mice vaccinated subcutaneously with a single dose of 10 µg of G glycoprotein preparation, with or without complete Freund’s adjuvant, were protected from lethal encephalitis caused by vesicular stomatitis virus. A subunit vaccine for vesicular stomatitis of cattle, horses, and swine avoids the hazards associated with attenuated and inactivated vaccines, such as vaccine breaks, reversion to virulence, or introduction of virus into potential wild reservoirs or arthropod hosts. Further, it is possible to distinguish serologically animals vaccinated with the subunit preparation from those that have had the clinical disease or that have been vaccinated with whole virus. This is an essential consideration both for epidemiological studies and for disease control or establishment of quarantine programs.

Vaccination against feline viral rhinotracheitis in kittens with maternally derived feline viral rhinotracheitis antibodies.

Abstract: The efficacy of a modified live-virus intranasal vaccine and a killed-virus adjuvanted parenteral vaccine in inducing protective immunity against feline viral rhinotracheitis (FVR) was evaluated in kittens with and without maternally derived FVR antibodies. The intranasal vaccine was given as a single dose to kittens 5 weeks old, and the parenteral vaccine was administered in 2 doses at 5 and 7 weeks of age. Seroconversion was delayed for 5 to 10 days in kittens with maternally derived antibodies, but occurred in all vaccinated kittens by 8 weeks of age. When virulent FVR virus was given, both vaccines provided satisfactory protection against disease but did not prevent infection. The results indicated that the modified live-virus intranasal vaccine or the killed-virus adjuvanted parenteral vaccine can be used successfully in kittens with residual maternally derived FVR antibodies.

Live varicella vaccine in severely immunodepressed children.

Abstract: One dose containing 3,100 PFU of a live attenuated Oka-strain varicella vaccine (Varilrix, Smith Kline-RIT, Belgium) was administered subcutaneously to 45 children, 26 of whom were suffering from acute leukaemia and 19 from solid malignant tumours Their immunological status had been severely compromised by chemotherapy as evidenced by markedly low values for all immunological parameters Of the 31 children seronegative for varicella at the time of vaccination, 70%, 85%, 75%, and 40% had varicella serum antibodies at 1, 2, 3, and 12 months after vaccination, respectively Evaluation of the immunological parameters indicated that they were of no predictive value regarding the antibody response of the patients to the vaccine Eight children (18%) developed varicella after vaccination In one case, the disease was caused by the vaccine virus while in another, the vaccine virus was probably also responsible The remaining six cases were caused by wild virus The antibody response and accompanying protection against disease induced by the vaccine in severely immunodepressed patients is acceptable, but clearly lower and of shorter duration than in normal subjects Thus, in immunocompromised patients, booster doses of the vaccine may be required at relatively short intervals

Active immunization against varicella of children with acute leukaemia or other malignancies on maintenance chemotherapy.

Abstract: Twenty-six patients with acute leukaemia and other malignancies susceptible to varicella were vaccinated with the Oka-strain live attenuated varicella vaccine during maintenance chemotherapy. All recipients showed no adverse clinical reactions. There was no spread of vaccine virus. Seroconversion was 94% in seronegative patients. Among those having low antibody titres before vaccination, a booster effect was demonstrable in 56%. None of the seroconverted recipients contracted varicella despite documented contact exposure. No case of herpes zoster occurred. The results suggest that, in immunocompromised children, live varicella vaccination has a protective effect against varicella infection which may result in a mortality rate of up to 7% in these patients.

Experience with the live Oka-strain varicella vaccine in children with solid tumours.

Abstract: A comparative evaluation of radioimmunoassay (RIA), indirect immunofluorescence, fluorescent antibody to membrane antigen, competitive inhibition RIA, and complement fixation methods for determining the immune status to varicella-zoster virus (VZV) showed that RIA was the most sensitive test. However, this test is still not regarded as being entirely satisfactory and possible reasons are discussed. To date, 28 children, mainly with solid tumours, have been inoculated with the Oka-strain live varicella vaccine. Two of these vaccinees developed minor reactions, but only 62% developed a RIA-detectable humoral response. Approximately 46% of the responders had lost induced antibody within 12 months of vaccination. None of the 6 vaccinees that have subsequently been in contact with varicella developed any illness suggesting that they had been protected.

Varicella vaccine: case studies.

Abstract: A live varicella vaccine (Oka strain) has been developed. Clinical trials in normal and high-risk children have been carried out successfully in Japan, the USA and Europe, leading to recent licensing of this vaccine in several countries. Characterization of the vaccine and the results of clinical trials are reviewed in this article.

Vaccination of children with malignant disease against varicella.

Abstract: Nineteen seronegative children and one young adult with malignant disease in remission and on maintenance chemotherapy were immunized with the Oka-strain live attenuated varicella vaccine (Varilrix). Side effects were moderate and a rash was seen in 50% of the patients after vaccination. Humoral immune response to the vaccine was tested by the fluorescent antibody to membrane antigen (FAMA) test, a simpler indirect immunofluorescence test (IFT), and an enzyme-linked immunosorbent assay (ELISA). The seroconversion rate after immunization varied according to the method used. Seven out of 8 responded by FAMA, 15 out of 20 by IFT, and 12 out of 20 by ELISA. A decline in post-vaccination varicella-zoster virus (VZV) antibodies was seen in some responders. In 2 children, detectable levels of passively transferred VZV antibodies at the time of vaccination, due to varicella-zoster immune globulin, may have interfered with or modified the response to the vaccine. Cross-reacting antibodies to herpes simplex virus may have possibly interfered with vaccine response in a third child. Six out of 8 children receiving a second vaccine dose showed a good serological response. Specific cell-mediated immune response to the vaccine, measured by lymphocyte proliferation tests, corresponded well with the humoral response in the initial study of 8 patients. Two children who had responded to the vaccine were exposed to varicella in their families without contracting the clinical disease.

Production of herpesvirus of turkeys in microcarrier culturing system--a new method for production of vaccine against Marek's disease

Abstract: A microcarrier (MC) culturing system for production of a vaccine against Marek's disease virus is presented. Cytodex-3 beads (Pharmacia) and DE-53 microgranular (Whatman) are the recommended microcarriers. Primary cells from chick embryo as well as cells from a quail cell line (QT-6, established from a Japanese quail) were found to be good hosts for growth of herpesvirus of turkeys (HVT). HVT, the vaccine strain against Marek's disease, was successfully grown and harvested on the above mentioned MCs and cells. The findings of this study, open new possibilities in the production of HVT for various purposes such as basic research and vaccine preparation.

The future of varicella vaccine.

Abstract: Based on conservative figures, an estimated 60 million varicella-zoster cases occur annually worldwide, highlighting the global significance of this disease. The development of a viable varicella vaccine, therefore, raises important questions as to the indications for its use in normal children, normal seropositive and seronegative adults, and immunocompromised patients. A review of the available data addresses the potential future role of the varicella vaccine in these groups.

Use of a quadrivalent modified-live bluetongue virus vaccine in wildlife species.

Abstract: Three hundred and twenty-seven animals comprised of deer, mouflon sheep and bighorn sheep were vaccinated with an experimental quadrivalent, modified-live, bluetongue virus (BTV) vaccine. No untoward effects due to the vaccine were noted nor were abortions observed in vaccinated pregnant mouflon sheep. Precipitating antibodies to BTV and epizootic hemorrhagic disease (EHD) virus were identified in the serum of several animals prior to vaccination. Virus neutralizing antibodies to 3 of the 5 serotypes of BTV which exist in the US were identified in the serum of 2 peninsular bighorn sheep.

Live varicella immunization in healthy non-immune nurses.

Abstract: Thirty-four varicella-zoster virus (VZV) seronegative nurses were vaccinated with the live varicella vaccine (Varilrix) and followed for periods of up to 36 months. No major vaccine reactions were observed. At 5 and 12 months, 94% of the nurses had seroconverted but at 3 years, only 64% retained antibody activity. However, lymphocyte transformation to VZV antigen was positive in 7 seronegative nurses, all of whom had previously seroconverted. The one nurse who developed chickenpox had not seroconverted after vaccination. Two out of 11 seroconverted nurses had a subclinical reinfection, as shown by a rise in antibody, upon exposure to varicella. In contrast, 4 out of 5 seronegative nurses who had refused vaccination developed chickenpox. Varilrix is therefore safe, immunogenic, and protective in adults and can be considered for routine use in susceptible health workers. However, it is still uncertain whether lifelong immunity is obtained with this vaccine. Both cell-mediated and antibody tests are needed for long-term assessment of immunity to chickenpox.

Monoclonal antibodies in virology

Abstract: The application of hybridoma technology to the preparation of monoclonal antibodies has had a strong stimulatory effect on many areas of virological research This development has expanded our knowledge with respect to antigenic variation among viruses and detailed analysis of complex antigenic structures of virus proteins and has also led to the elucidation of the molecular foundations of pathogenesis and virulence in model systems The practical importance of these results spans many important areas of applied virology such as the development of new viral vaccines, passive immunization and diagnosis of viral infections

Production of poultry viral vaccines in embryonated eggs.

Abstract: The review was written in attempt to summarize some aspects of current poultry viral vaccine production. Problems associated with the production of safe and effective viral vaccines were described. Embryonated eggs or CEF are used in veterinary medical research and in the production of viral vaccines owing to their advantages as a suitable substrate for a wide range of viruses.