tetano
Editor, Senior Moderator
Comp Immunol Microbiol Infect Dis
. 2026 Sep 14:130:102531.
doi: 10.1016/j.cimid.2026.102531. Online ahead of print.
Boopathi Ponnusamy 1 , Manoj Kumar 2 , Harshad Vinayakrao Murugkar 3 , Shanmugasundaram Nagarajan 3 , Chakradhar Tosh 3 , Sivasankar Panickan 1 , Dhruv Desai 4 , Semmannan Kalaiyarasu 3 , Dhanapal Senthilkumar 3 , Katherukamem Rajukumar 3 , Siddharth Gautam 3 , Vijendra Pal Singh 3 , Aniket Sanyal 3
Affiliations
The first outbreak of highly pathogenic avian influenza (HPAI) H5N8 virus in India occurred in 2016, initially affecting wild birds and later spreading to domestic and commercial chickens, causing severe morbidity and mortality. To investigate the host immune response, Specific Pathogen-Free (SPF) chickens were experimentally infected with three virus doses (10², 104, and 106 EID50). Immune-related gene expression of IL-1β, IL-6, IL-8, IL-10, TNF-α, IFN-α, IFN-β, IFN-γ, TLR-3, and TLR-7 was analyzed in brain and lung tissues at 6, 12, 24, 48, and > 48 h post-infection (hpi) using real-time PCR. No significant cytokine or TLR upregulation was observed in the 10² EID50 group. In contrast, chickens infected with 104 and 106 EID50 exhibited significant increases in IL-6, IL-8, and TLR-3 expression in the lungs and brains. Early cytokine and TLR activation at 24 hpi in the 106 EID50 group indicated a cytokine upregulation, likely contributing to rapid mortality at 45-47 hpi. In the 104 EID50 group, two birds survived until 14 days post-infection without marked cytokine or TLR upregulation, suggesting individual variation in innate immune responses. Flow cytometric analysis of peripheral blood mononuclear cells revealed earlier transient relative increase in the proportion of various subsets of lymphocytes followed by relative decrease, reflected by initial increases and subsequent decreases in the proportion of CD4 + , CD8 + , and MHC-II + cell populations. Overall, our findings indicate that H5N8-induced cytokine gene expression or dysregulation plays a critical role in disease pathogenesis and disease severity in chickens.
Keywords: Cytokines; H5N8; Outbreak; Real Time qPCR; SPF chickens; Transcripts.
. 2026 Sep 14:130:102531.
doi: 10.1016/j.cimid.2026.102531. Online ahead of print.
Dynamics of cytokines and toll-like receptor gene expression in chickens infected with different doses of H5N8 avian influenza virus
Boopathi Ponnusamy 1 , Manoj Kumar 2 , Harshad Vinayakrao Murugkar 3 , Shanmugasundaram Nagarajan 3 , Chakradhar Tosh 3 , Sivasankar Panickan 1 , Dhruv Desai 4 , Semmannan Kalaiyarasu 3 , Dhanapal Senthilkumar 3 , Katherukamem Rajukumar 3 , Siddharth Gautam 3 , Vijendra Pal Singh 3 , Aniket Sanyal 3
Affiliations
- PMID: 42748772
- DOI: 10.1016/j.cimid.2026.102531
Abstract
The first outbreak of highly pathogenic avian influenza (HPAI) H5N8 virus in India occurred in 2016, initially affecting wild birds and later spreading to domestic and commercial chickens, causing severe morbidity and mortality. To investigate the host immune response, Specific Pathogen-Free (SPF) chickens were experimentally infected with three virus doses (10², 104, and 106 EID50). Immune-related gene expression of IL-1β, IL-6, IL-8, IL-10, TNF-α, IFN-α, IFN-β, IFN-γ, TLR-3, and TLR-7 was analyzed in brain and lung tissues at 6, 12, 24, 48, and > 48 h post-infection (hpi) using real-time PCR. No significant cytokine or TLR upregulation was observed in the 10² EID50 group. In contrast, chickens infected with 104 and 106 EID50 exhibited significant increases in IL-6, IL-8, and TLR-3 expression in the lungs and brains. Early cytokine and TLR activation at 24 hpi in the 106 EID50 group indicated a cytokine upregulation, likely contributing to rapid mortality at 45-47 hpi. In the 104 EID50 group, two birds survived until 14 days post-infection without marked cytokine or TLR upregulation, suggesting individual variation in innate immune responses. Flow cytometric analysis of peripheral blood mononuclear cells revealed earlier transient relative increase in the proportion of various subsets of lymphocytes followed by relative decrease, reflected by initial increases and subsequent decreases in the proportion of CD4 + , CD8 + , and MHC-II + cell populations. Overall, our findings indicate that H5N8-induced cytokine gene expression or dysregulation plays a critical role in disease pathogenesis and disease severity in chickens.
Keywords: Cytokines; H5N8; Outbreak; Real Time qPCR; SPF chickens; Transcripts.