SELECTION OF MIMOTOPE PEPTIDES OF IMMUNODOMINANT EPITOPES OF S. TYPHI LPS USING PHAGE DISPLAY

• DOI: 10.22533/at.ed.813352305068

• Palavras-chave: -

• Keywords: phagotope, mimotope, S. Typhi LPS, Phage Display.

• Abstract:

  Introduction. Phage Display is a technique that enables the identification of
  immunodominant epitopes that can be proposed as immunogens in the
  development of vaccines. Liposaccharides (LPS) participate in the pathogenesis of
  the microorganism and induce the immune response in the host. However, due to
  its toxicity, it cannot be employed as an immunogen in vaccine development.
  Objectives. To select phagotopes of immunodominant epitopes of Salmonella
  Typhi LPS, evaluate if they present immunogenic properties and to analyze if the
  resulting antibodies against the phagotopes recognize S. Typhi LPS. Materials
  and Methods. Using Phage Display with a peptide library of 12 amino acids
  (BioLabs) and IgG from S. Typhi anti-LPS rabbit sera, phagotopes were selected.
  After obtaining DNA sequences, peptides conjugated with KLH were synthesized.
  The reactivity of the S. Typhi anti-LPS rabbit sera, anti-phagotopes and anti-
  peptides against LPS and peptides were evaluated. Using the same sera, S. Typhi
  LPS recognition was analyzed by Western blot. Results. Analysis of the DNA
  sequences of 073/2 and 073/14 phagotopes revealed the TDYA motif as a
  consensus sequence. Using these peptides and phagotopes, the following sera
  were obtained: anti-073/2, anti-073/14, anti-SP073/2-KLH and anti-SP073/14-
  KLH. Reactivity analysis of the anti-SP073/2-KLH and anti-SP073/14-KLH sera
  showed that both recognized S. Typhi LPS with an OD (415nm) of 0.35 and 0.73,
  respectively. Similarly, the homologous peptide was recognized with values of 0.55
  and 0.65 at a dilution of 1:50. With respect to the anti-073/2 and anti-073/14
  sera, they recognized both the LPS of S. Typhi and the peptides. Western blot
  analysis of the anti-LPS S. Typhi, anti-phages and anti-peptides sera showed
  recognition of the core region and lipid A of the S. Typhi LPS. Conclusion. The
  phagotopes selected with the anti-LPS serum of S. Typhi showed immunogenic
  properties. In addition, the synthetic anti-peptide antibodies generated with the
  phagotopes consensus sequence recognized both the homologous peptide and
  the LPS of S. Typhi. The results suggest the possible use of mimotope peptides in
  the design of an immunogenic protector against S. Typhi infections.