UNDERSTANDING CHICKEN IMMUNE RESPONSES IN RESISTANT AND SUSCEPTIBLE MHC B HAPLOTYPE LINES TO DIFFERENT INFECTIOUS BRONCHITIS VIRUS GENOTYPES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: ANIMAL HEALTH
• Reporting Frequency: Annual
• Accession No.: 1013359
• Project Start Date: Jul 6, 2017
• Project End Date: Sep 30, 2018
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671

Performing Department
Population Health & Reproduction

Non Technical Summary
An important and unused way of understanding immune responses is using animal models that show resistance and susceptibility characteristics to infectious diseases. We have worked on determining a model to test resistance and susceptibility to poultry respiratory diseases {infectious bronchitis virus (IBV)} as a way of understanding the basis of this resistance or susceptibility. in this project we are trying to validate this model testing different genotypes of IBVand checking the outcome in terms of resistance and suscpetibility on the lines we previously detected as resistant and susceptible. The results of these experiment will help understanding the basis of resistance to this diseases and will help strategize prevention measures securing the poultry supply.

Animal Health Component

(N/A)

Research Effort Categories

Basic

100%

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
311	3299	1090	100%

Knowledge Area
311 - Animal Diseases;

Subject Of Investigation
3299 - Poultry, general/other;

Field Of Science
1090 - Immunology;

Keywords

mhc b

immunology

resistance

susceptibility

ibv

Goals / Objectives
RESEARCH HYPOTHESISOur hypothesis is based on our preliminary results (1) and results by others (2, 3) suggesting involvement of the innate immune response in the different IBV resistance of the mentioned lines. We hypothesize that key components of the innate immunity play a crucial role in the early protection against different IBV genotypes. We propose to assess and compare, using the resistant-susceptible model, the innate immune responses elicited in these MHC congenic chicken lines at an early stage of infection.OBJECTIVESDemonstrate the effectiveness of the model by challenging MHC haplotype B2-line (resistant) and B19-line (susceptible), with three different IBV genotypes (nephropathogenic, respiratory and intestinal tissue tropism)Compare the immune responses, pathology and RNA expression of each of the challenged lines with each of the IBV genotypes

Project Methods
A total of 140 chickens (70 animals from each congenic line, 140 chicks total) will be divided into 7 groups: three groups will be composed of 20 birds from B2 chicken line, three groups will be composed of 20 birds from B19 chicken line. One group will be composed of 10 birds from each line and will serve as a non-challenged control. At 21 days of age an IBV antibody ELISA will be used to assess maternal antibodies. Challenge will be performed at 23 days of age with one IBV strain of specific tropism per group. Each virus will be inoculated via the oculo-nasal route. All groups will be evaluated daily for health and mortality.Clinical signs will be recorded in all chickens at 2, 4 and 6 days post challenge (dpc). Necropsies will be performed on 6 chickens per group at 2 and 6 dpc. Trachea, Harderian gland, kidney and cecal tonsils will be collected for histopathology and histomorphometry analysis as well as, RNA extraction and subsequent RNA-seq. Sera will be collected at 2 and 6 dpc for IFN-, IFN-β, IL-12 and TNF- ELISA. In addition, tears will be collected at 2 and 6 dpc for viral load assessment. At 14 dpc, tears and sera will be collected from the remaining birds (8 birds per group) to perform IBV IgA and IgG ELISA assays respectively.

Progress 07/06/17 to 09/30/18

Outputs
Target Audience:Poultry scientists and immunologists. Basic information generation to understand the innate responses in poultry against a respiratory disease challenge. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project trained one PhD student a post doc and several undergrads How have the results been disseminated to communities of interest?Other than publications, the scientific community have received this info through scientific presentations What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We were able to establish a model to investigate this disease and compare immune responses in two different IBV genotypes

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: -Da Silva A.P., Hauck R., H. Zhou, R. A. Gallardo, Understanding Immune Resistance to Infectious Bronchitis Using Major Histocompatibility Complex Chicken Lines. Avian Diseases. 2017. (In press) http://www.aaapjournals.info/doi/pdf/10.1637/11666-050117-Reg.1
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: - Da Silva. A. P, R. Hauck, H. Zhou, R. A. Gallardo. (2017). Understanding Resistance to Different Infectious Bronchitis Virus Genotypes. American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, Indianapolis, IN.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: -Da Silva. A. P, R. Hauck, H. Zhou, R. A. Gallardo. (2017). Major histocompatibility complex and genetic resistance to infectious bronchitis virus. 66th Western Poultry Disease Conference, Sacramento, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gallardo R. A., A.P. Da Silva, R. Hauck, H. Zhou. (2016). MHC and innate immune response as factors providing resistance to infectious bronchitis virus. American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, San Diego, TX.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Gallardo R. A., H. Zhou., K . Smith. (2015) Major histocompatibility complex and genetic resistance towards infectious bronchitis virus, American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, Boston, MA.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Da Silva A.P., R. Hauck, C. Kern, Y. Wang, H. Zhou, R.A. Gallardo. Effects of Chicken MHC Haplotype on Resistance to Distantly-Related Infectious Bronchitis Viruses. 2019. Avian Dis. 63:2, 310-317. https://www.aaapjournals.info/doi/pdf/10.1637/11989-103118-Reg.1

Progress 07/06/17 to 09/30/17

Outputs
Target Audience:Poultry scientists Poultry veterinarians Poultry immunologists and virologists Poultry companies Changes/Problems:We have not been able to measure the innate responses accordingly. We have planned ex vivo and in vitro experiments isolating cells and doing functional studies We will also re-visit time points where we are collecting the information What opportunities for training and professional development has the project provided?One PhD student has been trained through this funded project Also two undergrads and one post doc. How have the results been disseminated to communities of interest?Scientific manuscripts Scientific presentations Talks with veterinarians in the field What do you plan to do during the next reporting period to accomplish the goals?Clarify the innate immune response results in in vitro and ex vivo experiments, write the manuscript and continue further experimentation

Impacts
What was accomplished under these goals? We have tested the model including resistant and suscpetible chicken lines. Resuls have been clear in regards to clinical signs histopathology and gross pathology showing that the line B2 is resistant to IBV challenges with two differebt IBV's (M41 and Ark). Innate immune response measurements have shown inconsistent results, we are planning some pilot experiments and bench top trials ex vivo to eliminate the immune background and test the cytokine production by itself.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2017 Citation: -Da Silva A.P., Hauck R., H. Zhou, R. A. Gallardo, Understanding Immune Resistance to Infectious Bronchitis Using Major Histocompatibility Complex Chicken Lines. Avian Diseases. 2017. (In press) http://www.aaapjournals.info/doi/pdf/10.1637/11666-050117-Reg.1
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: - Da Silva. A. P, R. Hauck, H. Zhou, R. A. Gallardo. (2017). Understanding Resistance to Different Infectious Bronchitis Virus Genotypes. American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, Indianapolis, IN.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: -Da Silva. A. P, R. Hauck, H. Zhou, R. A. Gallardo. (2017). Major histocompatibility complex and genetic resistance to infectious bronchitis virus. 66th Western Poultry Disease Conference, Sacramento, CA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: -Gallardo R. A., A.P. Da Silva, R. Hauck, H. Zhou. (2016). MHC and innate immune response as factors providing resistance to infectious bronchitis virus. American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, San Diego, TX.
• Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gallardo R. A., H. Zhou., K . Smith. (2015) Major histocompatibility complex and genetic resistance towards infectious bronchitis virus, American Veterinary Medical Association / American Association of Avian Pathologists (AVMA/AAAP) Annual Meeting, Boston, MA.