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Avian Viral Vaccines

Research Team

  • Project leader:  Arshud Dar
  • Scientists: George Mutwiri, Suresh Tikoo
  • Technician:  Ken Lai

 

Overview

Viral infections are the biggest source of economic losses in poultry.  Moreover, recent trends of crossing over of species barriers by number of animal viruses and emergence and reemergence of novel and old more pathogenic viruses has increased the public health significance of avian viral infections.

Evasion of innate immune system by viruses is one of the primary factors in establishment of virus infections and  we believe that understanding of the manipulation of host cell microenvironment by viruses will enhance insight into the viral pathogenesis and immune modulation by viruses. We expect that this knowledge will facilitate the identification of molecular factors that permits or limit viral replication in cell and will offer maneuverable targets for the enhancement of host immunity. Likewise, molecular analysis of immune responses induced by different immune modulating agents (including adjuvants) will facilitate the search of agents that could be used for development of more effective and safer therapeutic and prophylactic agents against avian viral infections.

The development of long lasting, safe and effective vaccines protective in, neonate birds and in infected and uninfected flocks is one of the long term goals in control of viral infections in poultry. Despite good efficacy of live virus vaccines, due to interference of maternal antibodies in neonate birds and aggressiveness of disease symptoms in pre-infected birds, these live viral vaccines cannot be used in neonate chicks and infected flocks. Moreover, significant biological, epidemiological and safety issues associated with these live viral vaccines urge to introduce non invasive type of avian vaccines and delivery systems. However, weak cellular immune responses and short term protection offered by inactivated vaccines are the major impediments in development of this type of vaccines. Luckily, immune enhancing potential of recently discovered molecular adjuvants including defensins and polyphosphazene (PCEP) have presented new and exciting opportunities to develop more safe and more protective non-invasive vaccines.

The overall goal of our research group is to develop more effective and safer therapeutic and prophylactic agents against avian viral infections through enhanced understanding of avian viral pathogenesis and immune modulation by viruses and immune modulating agents.

Objectives

  1. Explore molecular basis of pathogenesis and immune modulation by avian viruses and immune modulating agents.
  2. Development of formulation and delivery systems to introduce safe and effective non-invasive type of poultry vaccines that could circumvent the risks associated with live viral vaccines.
    • Evaluation of vaccine formulations containing inclusion body hepatitis (IBH) viral capsid protein (protective antigen), avian defensin and polyphosphazene (PCEP) as vaccine candidates.
    • Evaluation of vaccines containing genetically linked IBH viral capsid protein and avian defensins.
    • Evaluation of optimal formulations and delivery system for protection against IBHV infection model.
    • Evalution of safety of new vaccine.

Future Direction and Vision

Following optimization of parameters for IBHV vaccine, we will use this model as a platform to develop other poultry vaccines including Newcastle disease virus vaccine and infectious bursal disease virus vaccines.  Presently only Marek's disease vaccine is used as in-ovo vaccine in poultry. We intend to develop more poultry viral vaccines to be adapted as in-ovo vaccines. Similarly, we have intention to manipulate and characterize viral determinants for the development of poultry vaccines.

We will also look for the basis of host cell and viral pathogen interactions.   For instance, we are interested in investigation of in-vitro and in-vivo changes in host cell innate immune machinery following infection of different types of avian viral pathogens including fowl adenovirus and infectious bursal disease virus. Similarly, we want to know about viral determinants that interact with host cell immune system and play significant role in immune evasion by viruses. We are also interested in investigations leading to information about the basis of variations in host responsiveness to vaccines and immune modulating agents.1

Funding Partners