Research Scientist Research Institute for Systems Biology and Medicine (RISBM), Russia
Introduction/Rationale: Whooping cough remains a one of the causes of infant mortality, but there has been an increase in adult cases in recent years. The whole-cell vaccine against B. pertussis - causative agent of the disease – is considered to induce an immune response similar to the natural one. Classically, B. pertussis is considered an extracellular pathogen that predominantly induces CD4⁺ T cell response. Presence and magnitude of B. pertussis-specific CD8⁺ T cell responses in human peripheral blood remain poorly characterized. The main goal is to compare B. pertussis-specific CD4+ and CD8+ composition in healthy donors who have had whooping cough or who have not had it
Methods: PBMC were isolated by Ficoll density gradient centrifugation from whole blood and stimulated with chemically inactivated B. pertussis or native immunodominant antigens. B. pertussis-specific CD8+ and CD4+ T cells were isolated by magnetic beads with following detecting via ELISpot. B. pertussis-specific T cells of high-responded donors were obtained from PBMC by INF-y secretion assay followed by flow cytometry analysis
Results: 1.T cell response to B. pertussis is detected in peripheral blood without expansion by ELISpot as IFNy-producing cells. Most donors have CD4+ T cell response and donors with HLA-A*02 also have CD8+ T cell response 2.B. pertussis-specific T cells are not restricted only by major antigens from acellular vaccines 3.The level of T cell response in peripheral blood does not differ between healthy and convalescent donors 4.Donors exhibit a high T сell response in peripheral blood immediately after recovery, which in most cases decreases within the first month
Conclusion: In summary, natural B. pertussis infection induces a transient increase of T cell response in peripheral blood, which peaks shortly after recovery and declines rapidly. Despite this temporary amplification, B. pertussis-specific T cell clonotypes do not become dominant in blood. CD8+ memory T cell presence is associated with HLA-A*02
