Correlating Antimicrobial Peptide Expression with Infection Status in Ixodes scapularis Ticks

Abstract:

I. scapularis ticks can transmit multiple diseases to humans, and understanding interactions between ticks and the pathogens they carry can improve prevention, diagnosis, and treatment of tick-borne illnesses. As in many arthropods, the immune system of I. scapularis ticks responds to pathogenic infections by expressing antimicrobial peptides. However, the effect of multi-pathogen infections, or coinfections, on antimicrobial peptide expression has not been described. DNA from I. scapularisticks was analyzed by PCR to identify uninfected, singly-infected, and coinfected ticks, and RNA was analyzed by quantitative PCR to determine the level of expression of the antimicrobial peptide defensin. We will present data on the proportion of ticks that carried multiple pathogens and correlation of infection status with defensin expression. Knowledge of the coinfection burden in I. scapularis can improve the accuracy of diagnosis and treatment of tick-borne diseases, while knowledge of the impact that coinfection status has on defensin expression may inform research on interactions between tick immune systems and combinations of infecting microbes, with the goal of developing novel therapeutic and preventive strategies for tick-borne diseases.