Abstract

Comparative Evaluation of Indigenously Developed Chitosan Based Haemorrhagic Septicemia Vaccine with Commercially Available Vaccine (HS-50) for Immunogenicity Production

Authors: Ali Abbas, Asfa Rasool and Sajjad Hussain

DOI: http://dx.doi.org/10.71081/cvj/2024.017

Abstract
Hemorrhagic septicemia (HS) is an important bacterial disease of cows and buffaloes distributed across the globe. In Pakistan it is the common and main infectious disease of the livestock. Mortality rate is very high in the diseased animals due to the rapid onset of the condition. Vaccination against the HS is the available practical way to control the disease. There are many types of the adjuvants, which are used in HS vaccines to enhance the efficacy and safety. Chitosan is a biopolymer obtained from chitin, has immune stimulatory properties and can serve as a suitable candidate as an adjuvant for vaccines and immunotherapies. Chitosan adjuvanted vaccine against hemorrhagic septicemia disease was aimed using two different concentrations of chitosan as adjuvant, quality testing of the prepared vaccines and comparative evaluation with commercially available vaccine (HS-50) for immunogenicity production. Shelf-life study of the vaccines was performed by keeping vaccines at two different temperatures i.e., 4? and 25? for two months. Rabbits and Swiss white albino mice were used in this study. Rabbits were placed in four groups, each comprising of 05 rabbits. Each rabbit group was inoculated with specific one vaccine like HS vaccine adjuvanted with chitosan at 3% (Group A) and 1.5% (Group B), HS-50 (Group C) and control group (D) with no vaccination. Blood sampling was done on days 0, 15, 30, 45 and 60. Immune response was checked through indirect hemagglutination test (IHA). It was found that results of the antibody titers produced by HS vaccine adjuvanted with chitosan @ 3% were protective and comparable with the commercial vaccine. Antibody titers produced by HS vaccine adjuvanted with chitosan @ 1.5% were moderate. The results of the antibody titers for vaccine groups (A &C) were significantly different from control group (P<0.05). No significant difference among the vaccine groups was found as (P>0.05). Challenge study in mice for fresh vaccine proved that protection provided by the HS vaccine adjuvanted with chitosan (3%) was good and comparable with the commercial vaccine HS-50. Shelf-life study results indicated that vaccines remain protective when stored at 4°C for two months. Protection against challenge was decreased for vaccines stored at 25°C for two months. As this study was performed in lab animals, results are suggestive that further studies should be performed in cattle and buffalo.

Keywords: Buffalo, Cattle, Chitosan nanoparticle, Haemorrhagic septicemia, Immunogenicity, Pasteurella multocida.