Cloning bovine cytokine cDNA fragments and measuring bovine cytokine mRNA using the reverse transcription-polymerase chain reaction

Bovine cytokine-specific primers and the reverse transcription-polymerase chain reaction (RT-PCR) were used to clone cDNA fragments that were specific for bovine IL-1α, IL-1β, IL-2, and IFN-γ. Specificity of the cDNA fragments was verified by sequence analysis based on known bovine IL-1α, IL-1β, IL-2, and IFN-γ gene sequences. In addition, RT-PCR was used to monitor cytokine mRNA expression in concanavalin A (Con A) and lipopolysaccharide (LPS)-stimulated bovine peripheral blood mononuclear cells (PBMC), and the results were compared with those obtained by measuring PBMC cytokine secretion using biologic assays. IL-1 activity in LPS-stimulated PBMC cultures was similar at 12 h and 24 h, although the activity decreased by approximately 40% at 48 h. IL-2 and IFN-γ activity in supernatants of Con A-stimulated PBMC cultures was low at 12 h and reached maximum levels at 48 h. RT-PCR transcript analysis detected an increase in IL-1α, IL-1β, IL-2, and IFN-γ mRNA expression that was usually correlated with the detection of these soluble cytokines by the bioassays. These results indicate that RT-PCR is a sensitive and effective method of obtaining cDNA probes and that this technique can be used to monitor bovine cytokine mRNA expression.