Biophysical and biochemical characterization of a recombinant Lyme disease vaccine antigen, CspZ-YA

Int J Biol Macromol. 2024 Feb;259(Pt 2):129295. doi: 10.1016/j.ijbiomac.2024.129295. Epub 2024 Jan 9.

Abstract

Lyme disease, caused by Lyme Borrelia spirochetes, is the most common vector-borne illness in the United States. Despite its global significance, with an estimated 14.5 % seroprevalence, there is currently no licensed vaccine. Previously, we demonstrated that CspZ-YA protein conferred protection against Lyme Borrelia infection, making it a promising vaccine candidate. However, such a protein was tagged with hexahistidine, and thus not preferred for vaccine development; furthermore, the formulation to stabilize the protein was understudied. In this work, we developed a two-step purification process for tag-free E. coli-expressed recombinant CspZ-YA. We further utilized various bioassays to analyze the protein and determine the suitable buffer system for long-term storage and formulation as a vaccine immunogen. The results indicated that a buffer with a pH between 6.5 and 8.5 stabilized CspZ-YA by reducing its surface hydrophobicity and colloidal interactions. Additionally, low pH values induced a change in local spatial conformation and resulted in a decrease in α-helix content. Lastly, an optimal salinity of 22-400 mM at pH 7.5 was found to be important for its stability. Collectively, this study provides a fundamental biochemical and biophysical understanding and insights into the ideal stabilizing conditions to produce CspZ-YA recombinant protein for use in vaccine formulation and development.

Keywords: Buffer screening; E. coli; Lyme borreliae; Protein formulation; Recombinant protein vaccine.

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry
  • Borrelia burgdorferi*
  • Escherichia coli / genetics
  • Humans
  • Lyme Disease Vaccines
  • Lyme Disease* / prevention & control
  • Seroepidemiologic Studies

Substances

  • Lyme Disease Vaccines
  • Bacterial Outer Membrane Proteins