# SCHISTOSOME - SNAIL COMPATIBILITY: UNDERLYING MECHANISMS

> **NIH NIH R01** · OREGON STATE UNIVERSITY · 1993 · $217,995

## Abstract

On account of the considerable burden placed on human populations by
Schistosoma mansoni in schistosome-endemic areas, an understanding of the
basic mechanisms responsible for transmission of these human parasites via
their intermediate molluscan hosts is desirable.  This research seeks to
understand how it is that a miracidium larva is able to penetrate a snail
and transform into a sporocyst without eliciting aggressive defensive
responses.  Since individual snails (Biomphalaria glabrata) may be
susceptible or resistant to individual S. mansoni, the cellular and
molecular bases for this variability are to be sought.  At least some
components of this mollusc's internal defense system are subject to
modulation by trematode parasites and by stress.  Therefore, following
treatments proven to modulate hemocyte activity, the influence of such
altered states will be evaluated in assays of snail resistance.  Assays
include in vitro phagocytosis, cytoadherence and cell mediated
cytotoxicity, and in vivo resistance to S. mansoni.  An hypothesis that the
compatibility of schistosome and snail is due in part to mimicry of
carbohydrate epitopes will be tested using polyclonal sera, with antigens
subjected to proteolytic degradation, and known carbohydrate epitopes used
as competing ligands.  Substantively improved quantification of in vitro
cytotoxicity will allow us to determine whether resistant plasma
accelerates sporocyst killing.  Another hypothesis implicating
lysosomally-derived, plasma enzymes in modulating resistance will be tested
both in vivo and in vitro using plasma from appropriately treated snails
and defined enzymes.  A functional role will be sought for a 50 kD plasma
component found uniquely in strains of snail which are resistant to the PR1
strain of S. mansoni.  Polyclonal antisera will be used in efforts to block
effector functions, and the affinity-purified plasma component will be
evaluated for its ability to facilitate recognition and/or cytotoxic
hemocyte effector functions.  Finally, the relevance of a novel
alpha-macroglobulin-like protein in snail plasma to outcomes of snail -
schistosome encounters will be investigated.

## Key facts

- **NIH application ID:** 3126571
- **Project number:** 5R01AI016137-11
- **Recipient organization:** OREGON STATE UNIVERSITY
- **SAM.gov UEI:** MZ4DYXE1SL98
- **Principal Investigator:** CHRISTOPHER JEFFREY BAYNE
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $217,995
- **Award type:** 5
- **Project period:** 1981-09-30 → 1996-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3126571

## Citation

> US National Institutes of Health, RePORTER application 3126571, SCHISTOSOME - SNAIL COMPATIBILITY: UNDERLYING MECHANISMS (5R01AI016137-11). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3126571. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*