Volume 2 • Issue 1 • 1000115 J Vaccines Vaccin ISSN:2157-7560 JVV an open access journal Short Communication Open Access Abd el-Razek et al. J Vaccines Vaccin 2011, 2:1 DOI: 10.4172/2157-7560.1000115 Keywords: RVFV vaccine; Nanoparticle CAP adjuvant; Alum; Adjuvant activity; Adjuvant side efects Introduction Rif Valley fever (RVF) is an arthropod-borne, multi-species zoonotic viral disease of livestock whose causative agent was frst isolated in the 1930s. It had been exclusively confned to the African continent, but RVF spread to the Middle East in 2000. Te occurrence of the disease is usually reliant on the presence of susceptible animals, a build-up of the mosquito vector population (usually associated with heavy rains) and the presence of the virus. Vaccination has been used for the control of RVF in southern and East Africa. Two types of vaccines have been described: Formalin-inactivated RVF vaccines have been used to immunize animals, laboratory workers, veterinarians and other people at high risk of exposure to RVFV. Te cost of the vaccine production, the requirement for multiple inoculations required for protective immune response limit its use just for veterinary purposes [1]. Outbreaks of RVF in animals can be prevented by a sustained programme of animal vaccination. Both modifed live attenuated vaccine (Smithburn and MP12 strains) and inactivated (M/S/258 and ZH-501) virus vaccines have been developed for veterinary use. Only one dose of the live vaccine is required to provide long-term immunity but the vaccine that is currently in use may result in spontaneous abortion if given to pregnant animals. Te inactivated virus vaccine does not have this side efect, but multiple doses are required in order to provide protection which may prove problematic in endemic areas [2-4]. An efective vaccine usually requires an adjuvant to increase the immune response. More than 100 compounds or formulations show some degree of adjuvant properties [5]. At the beginning of the 20th century, researchers experimented with a wide variety of organic and inorganic compounds including aluminium salts, mineral oil, and killed mycobacteria to improve the immunogenicity of vaccines [3]. Te most common adjuvants approved for use in currently licensed human vaccines are the aluminium based adjuvants [6]. Adjuvants have been necessary to improve vaccine efcacy in order to aford protection against infections. A key reason for this is that both attenuated virus preparations and, particularly, recombinant proteins are ofen poorly antigenic. In the past decade, several adjuvants have been evaluated in clinical trials. Calcium phosphate (CAP), MF59, aluminium (alum) compounds, and virosomes have been approved for human use in several European countries [7]. In the United States, alum compounds are the most extensively used adjuvants in licensed vaccines for humans. Although they efectively enhance immune responses, there are several disadvantages associated with their use [6,8,9]. Te disadvantages of alum-based adjuvants include the severity of local tissue irritation, the longer duration of the infammatory reaction at the injection site, strong T2 responses, minimal induction of cell-mediated immunity, and a propensity to elicit undesirable immunoglobulin E (IgE) responses [10-12]. Alum compounds have also been shown to increase the levels of potential undesirable homocytotropic antibodies in animal species [13]. Furthermore, alum-based vaccines are frequently inefective for the induction of antiviral immunity [4]. For these reasons, new adjuvants are being developed to enhance the immunity against weak antigens. New-generation adjuvants are designed to induce minimal side efects, enhance the duration of the immune response, and concurrently stimulate humoral responses. Furthermore, an ideal adjuvant would be biodegradable, economical, and simple to manufacture. In addition, it would have the potential to selectively trigger a defned class of immune response. Nanomaterials have unique physicochemical properties, such as ultra small size, large surface area to mass ratio, and high reactivity, which are diferent from bulk materials of the same composition. Tese properties can be used to overcome some of the limitations found in traditional vaccines [14]. Replacement of aluminium salts with calcium phosphate has long been described [15]. Eforts with calcium adjuvants have continued, and work with calcium phosphate nanoparticles has had some preclinical success [16]. CAP based viral vaccines induce a higher IgG2a response and a lower IgE response relative to the responses induced by alum *Corresponding author: Aly Fahmy Mohamed, The Holding Company for Biological Products, Vaccines and Drugs (VACSERA), 51 Wezaret El-Zeraa street, Dokky GIZA –Egypt, Tel: 202- 37611111 Ext. 3398; Fax: 202- 33483187; E-mail: alyfahmy2002@yahoo.com Received December 10, 2010; Accepted March 10, 2011; Published March 15, 2011 Citation: Abd el-Razek NEE, Shoman SA, Mohamed AF (2011) Nanocapsulated Rift Valley Fever Vaccine Candidates and Relative Immunological and Histopathological Reactivity in Out Bred Swiss Mice. J Vaccines Vaccin 2:115. doi:10.4172/2157-7560.1000115 Copyright: © 2011 Abd el-Razek NEE, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Nanocapsulated Rift Valley Fever Vaccine Candidates and Relative Immunological and Histopathological Reactivity in Out Bred Swiss Mice Noha Emad El-Din Abd el-Razek, Sahar A. Shoman and Aly Fahmy Mohamed* The Holding Company for Biological Products, Vaccines and Drugs (VACSERA), 51 Wezaret El-Zeraa street, Dokky GIZA –Egypt Abstract The present work aimed to compare the potentials of Alum and CAP as adjuvants and related immune response to RVFV vaccines candidates inactivated using different inactivants namely, Formalin, Beta-Propiolactone (BPL) and Ascorbic acid (AA). Potency (ED50) of inactivated vaccines was arranged in the order of BPL (0.006), AA (0.0024), and formalin (0.011) respectively. Data recorded revealed that BPL inactivated showed a fast inactivating effcacy and inactivation time was arranged as BPL (2 hrs) followed by formalin (6 hrs) and AA (within 24hrs). BPL – CAP adjuvanted RVFV vaccine showed a higher and long durative antibody level than that detected post immunization with the other RFVF vaccine formulations either alum or CAP adjuvanted vaccines. Limited histopathological changes detected post CAP adjuvanted vaccine compared with that detected post Alum adjuvanted one was detected. Journal of Vaccines & Vaccination J o u r n a l o f V a c c i n e s & V a c c i n a t i o n ISSN: 2157-7560