sybr-green-i and African-Horse-Sickness

Cytokine secretion is one of the main mechanisms by which the immune system is regulated in response to pathogens. Therefore, the measurement of cytokine expression is fundamental to characterizing the immune response to infections. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) is widely used to measure cytokine mRNA levels, but assay conditions should be properly evaluated before analyzing important equine infections through relative quantification of gene expression. The aim of this study was to develop and evaluate a set of RT-qPCR assays for a panel of the most common cytokines in horses involved in innate and adaptive immune responses. Eight cytokines (interleukin (IL)-1β, IL-2, IL-4, IL-10, IL-12, TNFα, IFNβ and IFNγ) and a housekeeping gene (β-actin) were detected and amplified with the same annealing temperature in a SYBR Green RT-qPCR assay of samples of mitogen-stimulated peripheral blood mononuclear cells from a healthy horse and whole blood from a horse infected with African horse sickness virus. The method gave good efficiency for all genes tested, allowing quantification of relative expression levels. These SYBR Green RT-qPCR assays may be useful for examining cytokine gene expression in horses in response to exposure to economically important pathogens.

Topics: Actins; African Horse Sickness; African Horse Sickness Virus; Animals; Benzothiazoles; Cytokines; Diamines; Gene Expression; Horses; Leukocytes, Mononuclear; Mitogens; Organic Chemicals; Quinolines; Reverse Transcriptase Polymerase Chain Reaction

In order to improve, ensure and accelerate the diagnosis of African horse sickness, a highly devastating, transboundary animal disease listed by the World Animal Health Organisation, (OIE) three novel diagnostic PCR assays were developed and tested in this study. The reverse transcription-PCR (RT-PCR) tests were the following: (a) a conventional, gel-based RT-PCR, (b) a real-time PCR with SYBR-Green-named rRT-PCR SYBR-Green-, and (c) a real-time PCR rRT-PCR with TaqMan probe (termed rRT-PCR TaqMan). The same pair of primers-directed against African Horse Sickness Virus (AHSV) segment 5, encoding the non-structural protein NS1, is used in the three tests listed above. The three PCR assays detected similarly the nine AHSV serotypes from cultivated viral suspensions of different origins. The RT-PCR assays provided high sensitivity ranging from 0.1 to 1.2TCID(50)/ml. The specificity was also high, considering that related viruses, such as Bluetongue virus, and other equine viruses, such as West Nile Virus, remained negative for RT-PCR amplification. The detection of AHSV virus can be completed within 2-3h. These results indicate that the novel PCR methods described in this paper provide robust and versatile tools that allow rapid and highly specific, simultaneous detection of all AHSV serotypes.

Topics: African Horse Sickness; African Horse Sickness Virus; Animals; Benzothiazoles; Chlorocebus aethiops; Diamines; DNA Primers; DNA, Viral; Electrophoresis, Agar Gel; Horses; Organic Chemicals; Polymerase Chain Reaction; Quinolines; Reverse Transcriptase Polymerase Chain Reaction; Sensitivity and Specificity; Serotyping; Taq Polymerase; Vero Cells; Viral Nonstructural Proteins