Mansonella perstans microfilaremic individuals are characterized by enhanced type 2 helper T and regulatory T and B cell subsets and dampened systemic innate and adaptive immune responses

PLoS Negl Trop Dis. 2018 Jan 11;12(1):e0006184. doi: 10.1371/journal.pntd.0006184. eCollection 2018 Jan.

Abstract

The filarial nematode Mansonella perstans is endemic throughout Africa, northern South America and the Caribbean. Interestingly, M. perstans-infected individuals present no distinct clinical picture associated with certain pathology. Due to its relatively silent nature, research on this tropical disease has been neglected, especially M. perstans-driven immune responses. A hindrance in obtaining data on M. perstans-specific responses has been the inability to obtain adult worms since their habitats in serous cavities are difficult to access. Thus, in this study, for the first time, we used Mansonella perstans worm antigen extract as stimulant to obtain filarial-specific recall and immunoglobulin responses from M. perstans microfilaremic individuals (Mp MF+) from Cameroon. Moreover, systemic immune profiles in sera and immune cell composition in peripheral blood from Mp MF+ and amicrofilaremic individuals (Mp MF-) were obtained. Our data reveal that Mp MF+ individuals showed significantly reduced cytokine (IL-4, IL-6 and IL-12p70) and chemokine levels (IL-8 and RANTES), but significantly higher MIP-1β as well as increased M. perstans-specific IgG4 levels compared to Mp MF- individuals. In contrast, upon re-stimulation with worm antigen extract, IFN-γ, IL-13, IL-10 and IL-17A secretion was enhanced in cell cultures from Mp MF+ individuals when compared to those from cultures of healthy European individuals. Moreover, analysis of immune cell composition in peripheral blood from Mp MF+ individuals revealed increased type 2 helper T (Th2), natural killer (NK), regulatory B and T cell (Breg and Treg) subsets but decreased type 1 regulatory T (Tr1) cells. In summary, this study deciphers for the first time, M. perstans-specific immune responses using worm antigen extract and shows that patent M. perstans infections have distinct Th2, Breg and Treg subsets accompanied with reduced systemic innate and adaptive immune responses and dominant filarial-specific IgG4 levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptive Immunity*
  • Adult
  • Aged
  • Animals
  • Antibodies, Helminth / blood
  • B-Lymphocyte Subsets / immunology*
  • Cytokines / metabolism
  • Female
  • Humans
  • Immunity, Innate*
  • Male
  • Mansonella / immunology*
  • Mansonelliasis / pathology*
  • Middle Aged
  • T-Lymphocyte Subsets / immunology*

Substances

  • Antibodies, Helminth
  • Cytokines

Grants and funding

This work and the position of MR is funded through a grant awarded to MJ, SW, LEL and AH from the German Research Council (DFG) within the "African-German Cooperation Projects in Infectiology" (HO 2009/10-1) and the BONFOR intramural funding program of the Medical Faculty of Bonn University. Furthermore, AH is financially supported by the German Ministry for Education and Research (BMBF initiative Research Networks for Health Innovations in Sub-Sahara Africa: TAKeOFF). In addition, AH and LEL are members of the Excellence Cluster Immunosensation (DFG, EXC 1023) and of the German Centre of Infectious Disease (DZIF).