A162 EXPULSION OF THE TAPEWORM HYMENOLEPIS DIMINUTA FROM MICE OCCURS INDEPENDENT OF SEROTONERIC SIGNALLING
Bibliographic record
Abstract
Helminth infestation is a global concern: millions of individuals suffer acute or chronic infections and the impact on domestic livestock is immense, where anthelminthic resistance is widespread. There are several components to the response against helminth parasites, the best-studied being Th2 immunity. Serotonin (5-HT), a signalling molecule of which 95% is produced in the gut, plays many roles in immunity and gut physiology. Enteric 5-HT content or 5-HT+ enterochromaffin (EC) cell numbers can be increased in response to infection with a helminth parasite. The relevance of these increases and their role, if any, in protection against helminths is unclear. Using infection with the rat tapeworm Hymenolepis diminuta in the non-permissive mouse host, we sought to determine: 1) changes in 5-HT content and 5-HT immunoreactive EC cell number in intestine; and, 2) the role of 5-HT in the Th2 immune response elicited by H. diminuta. Male BALB/c mice were infected with 5 cysticercoids of H. diminuta ± i.p. PBS or para-chlorophenylalanine (PCPA; 300 mg/kg, daily for 6 days), a tryptophan hydroxylase inhibitor, to inhibit 5-HT production. At necropsy at 8 or 11 days post-infection, worms were flushed from the small intestine and counted, and intestines and spleens were collected. 5-HT immunoreactive EC cells were identified by immunohistochemistry and 5-HT content in the bowel determined by ELISA. Splenocytes were stimulated with concanavalin A (2 μg/mL, 48h), supernatants were collected and IL-4, IL-5, and IL-10 measured by ELISA. Infection with H. diminuta resulted in increased splenic Th2 cytokine levels at days 8 and 11 post-infection; however, increases in 5-HT+ EC cells were not detected in the gut. Further, while infection with H. diminuta did not affect ileal 5-HT content at day 8 post infection, and contrary to observations in other rodent-helminth model systems, 5-HT levels were reduced in the ileum at 11 days post-infection. PCPA treatment depleted ileal 5-HT content, and this impacted neither the successful expulsion of H. diminuta nor the development (kinetics, magnitude) of Th2 immunity. These data indicate that serotonergic signalling is not essential to expel H. diminuta or the Th2 immune response evoked in response to infection. Whether this is restricted to H. diminuta or generally applicable to flatworm parasites needs to be determined in the future. CIHRNSERC, NSERC CREATE, Henry Koopmans Memorial Entrance Scholarship
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".