Cytokine gene expression in lymph nodes and spleens of jirds during a primary infection with brugia pahangx

A shift in dominant cytokine response has been hypothesized to be associated with the spectrum of clinical conditions seen in lymphatic filariasis patients. Jirds infected with Brugia pahangi develop an antigen specific lymphoproliferative response in renal lymph nodes (RLN) and a corresponding granulomatous inflammatory response by 14 days post-infection (DPI), both of which are subsequently downregulated. Examination of cytokine responses during this infection has begun using a quantitative competitive RT-PCR ELISA to measure cytokine gene expression. Total RNA was isolated from axillary LN, RLN and spleen at 14, 28, 56 and 150 DPI for analysis. Cytokine specific primers for jird IL2, IL-4, IL-5, IL-10 and IFN-y were used to amplify the cytokine-specific mRNA in the presence of a specific competitor RNA sequence for each cytokine. PCR products were quantitated using an ELISA procedure. Increased levels of IL-2 and IL-5 mRNA were seen during the initial stages of the infection (14 to 28 DPI). An increase in IL-4 mRBA was first detected 28 DPI in RLN and continued throughout the infection. Increased levels of IL-10 mRNA were first seen in the spleen 56 DPI and in all tissues at 150 DPI. This shift to a dominant Th2-like response is associated with the hyporesponsive, susceptible, microfilaremic state seen in this model. The limited early detection o-f IL-5 corresponds to the transient eosinophilia which occurs early in the infection.