Safety and infectivity of female cercariae in Schistosoma-naïve, healthy participants: a controlled human Schistosoma mansoni infection studyResearch in context

oleh: Jan Pieter R. Koopman, Emma L. Houlder, Jacqueline J. Janse, Miriam Casacuberta-Partal, Olivia A.C. Lamers, Jeroen C. Sijtsma, Claudia de Dood, Stan T. Hilt, Arifa Ozir-Fazalalikhan, Vincent P. Kuiper, Geert V.T. Roozen, Laura M. de Bes-Roeleveld, Yvonne C.M. Kruize, Linda J. Wammes, Hermelijn H. Smits, Lisette van Lieshout, Govert J. van Dam, Inge M. van Amerongen-Westra, Pauline Meij, Paul L.A.M. Corstjens, Simon P. Jochems, Angela van Diepen, Maria Yazdanbakhsh, Cornelis H. Hokke, Meta Roestenberg

Format: Article
Diterbitkan: Elsevier 2023-11-01

Deskripsi

Summary: Background: A controlled human infection model for schistosomiasis (CHI-S) can speed up vaccine development and provides insight into early immune responses following schistosome exposure. Recently, we established CHI-S model using single-sex male-only Schistosoma mansoni (Sm) cercariae in Schistosoma-naïve individuals. Given important differences in antigenic profile and human immune responses to schistosomes of different sex, we pioneered a single-sex female-only CHI-S model for future use in vaccine development. Methods: We exposed 13 healthy, Schistosoma-naïve adult participants to 10 (n = 3) or 20 (n = 10) female cercariae and followed for 20 weeks, receiving treatment with praziquantel (PZQ) 60 mg/kg at week 8 and 12 after exposure. Findings: The majority (11/13) participants reported rash and/or itch at the site of exposure, 5/13 had transient symptoms of acute schistosomiasis. Exposure to 20 cercariae led to detectable infection, defined as serum circulating anodic antigen levels >1.0 pg/mL, in 6/10 participants. Despite two rounds of PZQ treatment, 4/13 participants showed signs of persistent infection. Additional one- or three-day PZQ treatment (1 × 60 mg/kg and 3 × 60 mg/kg) or artemether did not result in cure, but over time three participants self-cured. Antibody, cellular, and cytokine responses peaked at week 4 post infection, with a mixed Th1, Th2, and regulatory profile. Cellular responses were (most) discriminative for symptoms. Interpretation: Female-only infections exhibit similar clinical and immunological profiles as male-only infections but are more resistant to PZQ treatment. This limits future use of this model and may have important implications for disease control programs. Funding: European Union's Horizon 2020 (grant no. 81564).