Dr. Wayne L. Hynes
Associate Professor of Biological Sciences
Track Coordinator, Biomedical Sciences
Director, Master's Degree Programs in Biological Sciences
Innate Immunity:
Currently the main emphasis of my research is the resistance (or lack there of) of ticks to microbial infection, and the role of the innate immune system and presence of antimicrobial proteins produced by ticks in such systems. How do some ticks survive microbial infections and become able to transmit organisms to vertebrate hosts? This project has indicated a number of potential antimicrobial mechanisms exist in certain ticks, and some of these may be lacking or not expressed in those ticks able to transmit organisms such as Borrelia burgdorferi, the causative agent of Lyme disease. We were the first to identify a defensin-like peptide from the hemolymph of certain ticks, which appears not to be induced in other ticks.
We have cloned and sequenced the gene for the defensin (varisin) from the hemocytes of D. variabilis and are currently examining in which tissues this agent is expressed. The focus of this project is to isolate the defensin gene from different tissues (e.g. hemolymph cells, fat bodies, midgut) and to determine at what time after bacterial challenge the varisin gene is expressed. This involves the isolation of RNA from various tissues, RT-PCR and cloning of the amplified products, sequencing, and various hybridization studies, perhaps including in situ studies. It also involves the use of real-time PCR to provide rapid results regarding tissue expression. We will be examining not only the expression of the gene but also whether there are any differences in the sequence of the gene or non-translated region to ascertain if there may be different isoforms of this product in the tick. In addition we are now looking at expression of the defensin and production of recombinant protein from bacterial cells.
Recently we determined the sequence of a defensin-like peptide expressed by tissues of another hard tick, Ixodes scapularis, the black-legged tick and vector of the Lyme disease agent Borrelia burgdorferi. Unlike the defensin from D. variabilis this new defensin does not appear to be processed and stored in the cells or released into the hemolymph. Does this difference explain why B. burgdorferi is able to make it through the hemolymph to the salivary glands and be transmitted by this vector? We will use information obtained from this study combined with those from the D. variabilis study to try and determine possible differences in the mechanisms of induction between the two tick genera.
