ELISA and direct immunofluorescence test to detect equine arteritis virus (EAV) using a monoclonal antibody directed to the EAV-N protein.

This research paper discusses how a specific type of antibody, called a monoclonal antibody, can be used to easily and quickly detect a horse virus known as equine arteritis virus. This detection method potentially improves over previous methods because it can find the virus even when the virus is not causing strong ill effects on animal cells.

Monoclonal Antibody Against EAV-N protein

• A monoclonal antibody (mAb) targeted at the equine arteritis virus (EAV) nucleocapsid (a protein structure that holds the virus’s genetic material) was employed in this research.
• This mAb was used in two different types of diagnostic tests to detect the virus: the enzyme-linked immunosorbent assays (ELISAs) and direct immunofluorescence tests (DIFTs).

Assays with Different Virus Antigens

• The ELISAs were conducted using different sources of viral antigen (parts of the virus that provoke an immune response).
• These antigens are typically used in such tests because antibodies in a patient’s blood will bind to them if that patient has been exposed to the virus.

Labelled mAb for DIFTs

• The same antibody was labeled with a fluorescent compound to be used in DIFTs.
• This type of test uses fluorescence to indicate if the specific antibody is present, and thus, if the patient has been exposed to the virus the antibody is tailored to recognize.

Detection in Various EAV Strains

• The study found that this monoclonal antibody was useful for detecting different strains of the EAV in both the ELISA and DIFT.
• It was able to detect the virus in semen and tissue samples after they were processed in different cell lines.

Potential Replacement of Previous Tests

• The researchers indicated that the ELISA they used could replace another diagnostic test, the microneutralization test, in most cases.
• The ELISA offers an easier and quicker method of confirming whether the cell cultures exhibit a cytopathic effect specific to EAV.

DIFT Sensitivity

• The study also noted that the DIFT was more sensitive than both the ELISA and the microneutralization test.
• It could detect EAV antigen in cell cultures even when the cytopathic effect is very weak or non-existent, thus making it an extremely effective diagnostic tool.