# SECRETORY DEFENSES AGAINST GIARDIA LAMBLIA

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN DIEGO · 1987 · $249,434

## Abstract

Because the duration and severity of giardiasis are extremely variable, it
is important to study the effects of components of the intestinal milieu on
survival and behavior of G. lamblia.  Breast milk is a rich source of
immune and non-immune secretory factors.

In the initial grant period, non-human (but not cow, or goat) milk was
shown to kill G. lamblia trophozoites in vitro.  The kiling, which was
antibody-independent, required a bile salt and is due to milk bile salt
stimulated lipase (BSL).  Human duodenal (but not colonic) mucus protected
the parasites from milk and also promoted their attachment.  These studies
lead logically to the specific aims of the proposed continuation.

1. To determine the cellular and molecular mechanisms of non-immune killing
of G. lamblia by human milk.  2. To elucidate the interactions of G.
lamblia with complex elements of the human intestinal milieu; including:
a) trophozoite attachment to human intestinal epithelial cells (IEC) and
effects of IEC on parasite survival; b) chemotaxis of G. lamblia toward IEC
or its metabolites; c) purification and characterization of the mucus
component(s) which promote attachment and protect the parasites.  3. To
delineate the effects of secretory antibodies (from human milk) on G.
lamblia behaviors, including:  attachment to IEC, chemotaxis, growth,
survival, and killing by BSL.  4. To isolate and analyze G. lamblia
behavioral mutants.  5. To determine a) whether attachment or chemotaxis
mutants are infective for mice and b) whether NHM and/or human secretory
antibodies can passively protect mice from G. lamblia.

Information gained from these studies will provide increased understanding
of the roles of immune and non-immune host secretory factors upon the
course of human giardiasis.

## Key facts

- **NIH application ID:** 3129300
- **Project number:** 5R01AI019863-06
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN DIEGO
- **SAM.gov UEI:** UYTTZT6G9DT1
- **Principal Investigator:** FRANCES D. GILLIN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $249,434
- **Award type:** 5
- **Project period:** 1982-09-01 → 1989-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129300

## Citation

> US National Institutes of Health, RePORTER application 3129300, SECRETORY DEFENSES AGAINST GIARDIA LAMBLIA (5R01AI019863-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3129300. Licensed CC0.

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