C3h henrj

Six- to 8-week-old specific-pathogen-free (SPF) female C57BL/6JRj, BALB/cJRj, and C3H/HeNRj mice (Janvier, France) were used for the experiments. The trichostrongyloid nematode H. polygyrus was maintained by serial passage in C57BL/6 mice. Specific-pathogen-free larval I. ricinus ticks were obtained from batches of eggs from two adult females after they had fed on laboratory beagle dogs (license number H0078/10, Landesamt für Gesundheit und Soziales, Berlin, Germany). The absence of tick-borne pathogens in the tick larvae used for experimentation was surveyed by published PCRs (33 (link), 34 (link)) for the detection of a 153-bp fragment of the hbb gene of Borrelia burgdorferisensu lato, a 203-bp fragment of the gltA gene of spotted fever Rickettsia spp., a 602- to 639-bp fragment of the 18S rRNA gene of piroplasmida (33 (link)), and a 257-bp fragment of the 16S rRNA gene of the Anaplasmataceae (34 (link)) in DNA isolated (33 (link)) from subsets of 20 larvae randomly chosen from each tick batch. Borrelia afzelii-infected I. ricinus nymphs were derived from larvae that had engorged on experimentally infected mice (license number 23-2347-A-24-1-2010, Landesamt für Umwelt, Gesundheit, und Verbraucherschutz, Potsdam, Germany).

Normal testes were obtained from post-mortem donors (18-79 years) or after orchidectomy (prostate cancer patients not responding to hormonal therapy, 66-88 years), and processed within 2 hours of surgery. Only testes displaying normal spermatogenesis, as assessed by transillumination, were used in the study. The procedure was approved by the French National Agency for Biomedical Research (authorization PF S09-015) and Ethics Committee Ouest V, Rennes, France (authorization DC-2016-2783). Seven-week-old male wild type mice C3H/HeNRj (from Janvier Labs) were sacrificed using increasing levels of carbon dioxide and the testes were collected for organotypic testis culture as described hereafter. Mice were housed under standard conditions in the facilities of Rennes I University. Work on animals was performed in compliance with French and European regulations on the care and protection of laboratory animals.