Cytokine mRNA expression in leukocytes of efferent lymph from stimulated lymph nodes in pigs

To test the hypothesis that characteristic cytokine responses occur in stimulated porcine lymph nodes (LNs), lymph node efferent ducts were surgically cannulated. Efferent lymph (EL) leukocytes were collected before and after stimulation of LNs with mitogens [bacterial lipopolysaccharide (LPS) or phytohemagglutinin-P(PHA-P)] and antigens [hen egg white lysozyme (HEWL) or purified protein derivative of tuberculin (PPD)]. Cytokine mRNA expression was evaluated by quantitative reverse transcription polymerase chain reaction (Q-RT-PCR). Interleukin (IL)-1α was predominantly produced after all stimuli except for HEWL after which tumour necrosis factor (TNF)-α message was dominant. None of the stimuli induced message for IL-2, IL-4 or IL-8. Other cytokine mRNAs were produced in variable amounts and percentage of overall production of each cytokine message was in the following descending rank: LPS: IL-1α, TNF-α, interferon (IFN)-γ, IL-10, IL-12-p35, IL-6, IL-12-p40 and TNF-β; PHA-P: IL-1α, TNF-α, IL-10, IFN-γ, IL-12-p40 and TNF-β; HEWL: TNF-α, IL-1α, IFN-γ, IL-10, IL-6, IL-12-p40, TNF-β and IL-12-p35 and PPD: IL-1α, IFN-γ, TNF-α and IL-10. Time course response of cytokines revealed early (IL-1α, 10, TNF-α) and intermediate (IL-12-p40, TNF-β, IFN-γ) responses for PHA-P and early (IL-1α, 6, 10, IL-12-p35, IL-12-p40, TNF-α), intermediate (TNF-β, IFN-γ) and late (IL-1α, 6) for LPS. Cytokine mRNA response induced by HEWL was early (IL-α, IFN-γ), intermediate (IL-10, IL-12-p40, TNF-β), late (IL-1α, IL-12-p35) and very late (IL-1α, 6, 10, IL-12-p40, TNF-α). In Bacillus Calmette-Guérin (BCG) sensitized pigs, stimulation of LNs with PPD induced message for IL-1α, 10, TNF-α and IFN-γ which peaked at 24 h. Cytokine mRNAs varied by stimulus and differed for antibody and cell-mediated immune response.