Towards Improved Use of Vaccination in the Control of Infectious Bronchitis and Newcastle Disease in Poultry: Understanding the Immunological Mechanisms

Abstract

Infectious bronchitis (IB) and Newcastle disease (ND) are two important diseases of poultry and have remained a threat to the development of the poultry industry in many parts of the world. The immunology of avian has been well studied and numerous vaccines have been developed against the two viruses. Most of these vaccines are either inactivated vaccines or live attenuated vaccines. Inactivated vaccines induce weak cellular immune responses and require priming with live or other types of vaccines. Advanced technology has been used to produce several types of vaccines that can initiate prime immune responses. However, as a result of rapid genetic variations, the control of these two viral infections through vaccination has remained a challenge. Using various strategies such as combination of live attenuated and inactivated vaccines, development of IB/ND vaccines, use of DNA vaccines and transgenic plant vaccines, the problem is being surmounted. It is hoped that with increasing understanding of the immunological mechanisms in birds that are used in fighting these viruses, a more successful control of the diseases will be achieved. This will go a long way in contributing to global food security and the economic development of many developing countries, given the role of poultry in the attainment of these goals.

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

“…This has been shown to provide protection from morbidity and mortality in challenge studies [447]. One disadvantage of many killed vaccines is the potential for a weak cellular response, thus requiring priming with live or other vaccine types [448]. Certain nonpathogenic lentogenic natural strains have been considered for use as vaccines since there is cross protection against all pathotypes of NDV.…”

“…An alternative means of production is through cell culture [450]. Recent work has been done to produce newer vaccines based on modern molecular techniques [431,448,451]. These recombinant vaccines often use either nonpathogenic or replication deficient virus as the delivery vehicle for an antigen against the disease of choice [120,452].…”

Infectious Bronchitis Virus (Gammacoronavirus) in Poultry Farming: Vaccination, Immune Response and Measures for Mitigation

“…These immune cells represent cytostatic activity, increased antigen presentation on the surface of APCs (macrophages and dendritic cells) and, subsequently, the causes of the expression of MHC-I molecules [119]. Moreover, the activation of CD8+ (cytotoxic) and CD4+ (helper) T cells might be affected in IBV infection directly for virus clearance, resulting in damage to the bird's adaptive responses [120]. The dendritic cells (DCs) of the chicken act as phagocytic and antigen-presenting cells (APC) by increasing the expression of MHC class I and II molecules on their surface in response to antigens from moving pathogens [121].…”

Update on the Inactivation Procedures for the Vaccine Development Prospects of a New Highly Virulent RGNNV Isolate

“…Current vaccines can be classified into four main groups: whole-pathogen (traditional), recombinant, proteinbased, and nucleic acid vaccines [2]. Most veterinary vaccines in use today fall into the former category because of their cost-effectiveness and/or the insufficient knowledge of many pathogens at the molecular level [3][4][5][6][7]. Whole-pathogen vaccines consist of liveattenuated or weakened microorganisms, which usually yield improved immunological assets versus killed or inactivated microorganisms.…”

“…Whole-pathogen vaccines consist of liveattenuated or weakened microorganisms, which usually yield improved immunological assets versus killed or inactivated microorganisms. In comparison, the latter presents substantial biosafety and handling advantages [2] and thus a higher market acceptance in the animal production industry, including aquaculture [3][4][5][6][7].…”