Adults from Kisumu, Kenya have robust gamma delta T cell responses toSchistosoma mansoni, which are modulated by tuberculosis

• Authors: Taryn A. McLaughlin, Emory University; Jeremiah Khayumbi, Kenya Medical Research Institute; Joshua Ongalo, Kenya Medical Research Institute; Daniel Matete, Kenya Medical Research Institute; Joan Tonui, Kenya Medical Research Institute; Benson Muchiri, Kenya Medical Research Institute; Loren E. Sasser, Emory University; Angela Campbell, Emory University; Salim Allana, Emory University; Samuel Gurrion Ouma, Kenya Medical Research Institute; Felix Odhiambo Hayara, Kenya Medical Research Institute; Neel Gandhi, Emory University; Cheryl Day, Emory University
• Journal Title: PLOS NEGLECTED TROPICAL DISEASES
• Volume: Volume 14, Number 10
• Publisher: PUBLIC LIBRARY SCIENCE | 2020-10-01, Pages 1-21
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1371/journal.pntd.0008764
• Subjects: Biology, Parasitology; Health Sciences, Immunology
• Keywords: Science & Technology; Life Sciences & Biomedicine; Infectious Diseases; Parasitology; Tropical Medicine; SCHISTOSOMA-MANSONI; IMMUNE-RESPONSES; CYTOKINE PRODUCTION; INFECTION; JAPONICUM; LYMPHOCYTES; INDUCTION; COMMUNITY; ASSAYS; WORM

Abstract

Schistosoma mansoni (SM) is a parasitic helminth that infects over 200 million people and causes severe morbidity. It undergoes a multi-stage life cycle in human hosts and as such stimulates a stage-specific immune response. The human T cell response to SM is complex and varies throughout the life cycle of SM. Relative to the wealth of information regarding the immune response to SM eggs, little is known about the immune response to the adult worm. In addition, while a great deal of research has uncovered mechanisms by which co-infection with helminths modulates immunity to other pathogens, there is a paucity of data on the effect of pathogens on immunity to helminths. As such, we sought to characterize the breadth of the T cell response to SM and determine whether co-infection with Mycobacte-rium tuberculosis (Mtb) modifies SM-specific T cell responses in a cohort of HIV-uninfected adults in Kisumu, Kenya. SM-infected individuals were categorized into three groups by Mtb infection status: active TB (TB), Interferon-γ Release Assay positive (IGRA+), and Inter-feron-γ Release Assay negative (IGRA-). U.S. adults that were seronegative for SM antibodies served as naïve controls. We utilized flow cytometry to characterize the T cell repertoire to SM egg and worm antigens. We found that T cells had significantly higher proliferation and cytokine production in response to worm antigen than to egg antigen. The T cell response to SM was dominated by γδ T cells that produced TNFα and IFNγ. Furthermore, we found that in individuals infected with Mtb, γδ T cells proliferated less in response to SM worm antigens and had higher IL-4 production compared to naïve controls. Together these data demonstrate that γδ T cells respond robustly to SM worm antigens and that Mtb infection modifies the γδ T cell response to SM.