Document Type

Thesis - Open Access

Award Date

2026

Degree Name

Master of Science (MS)

Department / School

Veterinary and Biomedical Sciences

First Advisor

Sunil Mor

Abstract

Avian metapneumovirus (aMPV) is a respiratory pathogen that causes Turkey Rhinotracheitis (TRT) in turkeys and Swollen Head Syndrome (SHS) in chickens. The infection leads to facial swelling, nasal discharge, reduced egg production, and poor growth. This virus is classified into four subgroups: aMPV-A, B, C, and D, with two other novel subgroups, in which aMPV-A, B, and C are most prevalent in the commercial flocks. In early 2024, aMPV-A and B outbreaks have been reported in the US, resulting in severe economic losses. An economic assessment estimates around $112 million in losses in Minnesota and up to $434 million in Iowa, surpassing HPAI losses, illustrating the growing financial burden of the disease on the U.S. poultry sector. Transmission occurs primarily via aerosol and direct contact, producing inflammation and lesions in the nasal turbinates, trachea, and nasal sinuses. In my thesis, the literature review section summarizes the etiology, structure, subgroups, distribution, pathogenesis, lesions, transmission of disease, economic impact, and current diagnostic methods. In addition, I discussed in detail the types and structures of antibodies, monoclonal and polyclonal antibodies, their differences, and the hybridoma technique for producing monoclonal antibodies (mAbs). mAbs offer higher specificity and reproducibility than polyclonal antibodies (pAbs) and are widely used for diagnostic assay development, such as ELISA (Enzyme-linked immunosorbent assay), indirect immunofluorescence assay (iIFA), and immunohistochemistry (IHC). Although traditional diagnostic methods, such as RT-PCR, are available, reliable assays for detecting the virus in fixed tissues and cultured cells are still lacking. Additionally, isolation of aMPV is highly challenging due to a limited detection window of seven days post-infection, and direct visualization of CPEs (cytopathic effects) is highly subjective and time-consuming. Therefore, mAbs-based assays such as IFA and IHC play a significant role in accurate diagnosis, enabling the early and confident detection. The experimental component of my thesis focused on producing and characterizing mAbs against nucleoprotein (N protein) of aMPV-B. Using hybridoma technology, we recovered four stable primary clones: two showed stronger subgroup-specific reactivity to aMPV-B, and two showed cross-reactivity with both aMPV-A and B. However, no clones showed reactivity to aMPV-C. Additionally, pAbs exhibit cross-reactivity with all circulating subgroups in the US. The optimized IHC and IFA show enhanced sensitivity and antigen visualization and detection. These findings confirm that N protein specific mAbs are reliable tools for detecting aMPV-B and provide a foundation for the development of standardized immunodiagnostic kits.

Publisher

South Dakota State University

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Rights Statement

In Copyright