FIG. 4.
Expression of IFN-β, TNF-α, and IL-6 mRNAs in the spleens of Lpsn and Lpsd mice injected with serovar Typhimurium and S. aureus. Lpsn (Sn and BALB/c [Balb]) and Lpsd (Cr and BALB/c/l [Balb/l]) mice (three animals per strain) were injected intravenously with 15 μg of killed serovar Typhimurium (Stm) or S. aureus (Sa) per g of body weight. Untreated mice served as controls (C). One hour after treatment, the mice were sacrificed and their spleens were removed and homogenized, as described in Materials and Methods. Total spleen RNA was extracted separately for each animal and pooled for the three identically treated animals of each group. Ten micrograms of each RNA pool were used for detection of cytokine mRNA in an RPA with a cytokine template set. Two constitutive gene probes (L32 and GAPDH [glyceraldehyde-3-phosphate dehydrogenase]) for standardization of RNA amounts were also used according to the instructions of the manufacturer.