Immunological aspects of the efficiency of protectotype vaccination strategy against chicken infectious bronchitis.
BACKGROUND
One of the most commonly applied protectotype vaccination protocol against infectious bronchitis (IB) in broiler chickens in the EU is simultaneous or alternate use of Ma5 and 4/91 vaccine strains. After IB vaccination and infection, systemic and upper respiratory tract (URT), humoral and cell-mediated immunity (CMI), are stimulated. The level of this stimulation correlates with the level of protection against IB.


RESULTS
We've investigated the development of URT and systemic, cell-mediated and humoral immunity in commercial broiler chickens vaccinated with Ma5 and/or 4/91 strains at hatch day. We've demonstrated that the group vaccinated with Ma5 and 4/91 strain simultaneously developed the most desirable immunity which reflects the level of CD8+T cells stimulation in spleen and Harderian gland, as well as the level of IgA and IgY in URT washings and serum and their cross-reactivity with 7 IBV strains.


CONCLUSIONS
Although we did not demonstrate directly why Ma5 + 4/91 protocol is so efficient it seems that it combines the benefits of monovalent vaccination with either Ma5 or 4/91 and while Ma5 seems to stimulate CMI more efficiently, the 4/91 strain generates a wider spectrum of immune system cross-reactivity and higher URT IgA production.
Departemnt of Poultry Diseases, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, Olsztyn, 10-719, Poland. marcin.smialek@uwm.edu.pl.
Marcin
M
Smialek
Departemnt of Poultry Diseases, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, Olsztyn, 10-719, Poland.
Bartlomiej
B
Tykalowski
Departemnt of Poultry Diseases, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, Olsztyn, 10-719, Poland.
Daria
D
Dziewulska
Departemnt of Poultry Diseases, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, Olsztyn, 10-719, Poland.
Tomasz
T
Stenzel
Departemnt of Poultry Diseases, Faculty of Veterinary Medicine, University of Warmia and Mazury, Oczapowskiego 13, Olsztyn, 10-719, Poland.
Andrzej
A
Koncicki
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002645:Chickens; D018352:Coronavirus Infections / Q000276:immunology / Q000662:veterinary*; D003429:Cross Reactions; D007109:Immunity / Q000276:immunology*; D007070:Immunoglobulin A / Q000097:blood; D001351:Infectious bronchitis virus / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D007070:Immunoglobulin A; D014765:Viral Vaccines
CMI; Chicken; Humoral immunity; IB; Protectotype vaccination strategy