E-Poster with pre-recorded video presentation Lorne Infection and Immunity 2021

Age-dependent innate and adaptive cellular immune responses in malaria-naive children and adults. (#220)

Jessica R Loughland 1 2 , Nicholas L Dooley 2 , Damian Oyong 3 , Dean W Andrew 2 , Arya SheelaNair 2 , Peta E Tipping 1 , Nick M Anstey 1 , Gabriela Minigo 1 4 , Michelle J Boyle 1 2
  1. Menzies School of Health Research, Darwin, Northern Territory, Australia
  2. QIMR-Berghofer, Herston, QLD, Australia
  3. Seattle Children's Research Institute, Seattle, USA
  4. College of Health and Human Sciences, Charles Darwin University, Darwin, Northern Territory, Australia

Children are the most at-risk group for severe and symptomatic malaria, with age and exposure to malaria independently impacting the ability of children to gain protective antibodies. To improve outcomes for children, an increased understanding of the impact of age on innate and adaptive cellular immune responses is necessary. We investigated novel antigen-presenting cell subsets (monocytes and Vδ2 γδ T cells) and T-follicular helper (Tfh) cell activation in malaria-naive children and adults after in-vitro stimulation with Plasmodium-infected RBCs (iRBCs). After iRBC stimulation, we show age-dependent differences in monocytes from malaria-naive adults and children. Children produce more cytokines including IL-10, IL-1β, and IL-6 compared to adults and children have more polyfunctional (multiple-cytokine) producing monocytes. Further, adults had a higher proportion of Vδ2 γδ TNF/IFNγ producing cells compared to children. In contrast, Tfh cell subsets were similarly activated after in-vitro iRBC stimulation in both malaria-naive children and adults. This finding contrasts our previous data of age-dependent differences to Tfh activation in children and adults with symptomatic naturally acquired malaria and reveals intrinsic differences in innate cell subsets between children and adults in response to iRBCs. Together these data inform our understanding of age-dependent differences that contribute to the development of protective anti-malarial immunity.