Assessment of Transcriptional Activity of Borrelia burgdorferi and Host Cytokine Genes During Early and Late Infection in a Mouse Model

Abstract
Differential gene expressions by Borrelia burgdorferi spirochetes during mammalian infection and host cytokines genes were assessed. Despite the recent advances in gene transcription detection technology, there has been limited transcriptional analysis of large clusters of B. burgdorferigenes. In an initial survey to understand the global effect of host immune response on gene transcription of B. burgdorferi during infection in the mouse model, expression profiles of 43 different genes were selected, including those presumed to be involved in attachment, cell envelope, metabolism, complement regulation, cellular processes, and replication. We used a RT-qPCR based method on the low-density array (LDA) format to compare transcriptional levels of selected B. burgdorferi genes and 19 mouse chemokines and cytokines in mice during early (3 weeks) and late (2 months) infection. The amounts of B. burgdorferi RNA and cDNA available from collected mouse tissues are limited, which restricts the number of analyzable genes. To overcome this problem, a preamplification technique was used to enhance sensitivity and fidelity of the RT-qPCR, especially for low-abundance target genes that increases fidelity of target genes that can be analyzed. LDA represents a valuable approach for sensitive and quantitative gene transcription profiling for understanding this important vector-borne disease.