Identification and characterization of guinea pig interleukin-6 (IL-6) (134.15)

Abstract

The guinea pig (Cavia porcellus) is an important research model for a number of diseases of the lung, including chronic obstructive pulmonary disease (COPD), tuberculosis, and asthma. Inflammation appears to play an important role in the progression of these various diseases. An important focus in understanding the etiology of these various diseases is the detection and quantification of inflammatory mediators such as cytokines and prostaglandins. Measurements of these inflammatory mediators can also provide a method by which efficacy of potential therapeutics is assessed. A key mediator of inflammation in a number of experimental systems is interleukin-6 (IL-6). The sequence of guinea pig IL-6 has not been published. To enable the development of reagents for the detection and quantification of IL-6 in guinea pig samples, recombinant guinea pig IL-6 was developed through the isolation of mRNA from LPS-stimulated guinea pig splenocytes, amplification of the cDNA, and cloning and expression using appropriate vectors in E. coli. Following refolding and purification, the protein was found to be highly reactive in a B9 mouse hybridoma proliferation assay. The observed ED50 of guinea pig IL-6 was comparable to the observed ED50 of mouse IL-6 (4-8 pg/mL) and human IL-6 (8-20 pg/mL). Sequence analysis revealed that guinea pig IL-6 was approximately 55% homologous with mouse IL-6, and approximately 57% homologous with human IL-6.