# CELLULAR INTERACTIONS WITH COMPLEMENT AND PROPERDIN

> **NIH NIH R01** · VIRGINIA COMMONWEALTH UNIVERSITY · 1989 · $238,602

## Abstract

Because of its precedence in phylogeny and its freedom from the requirement
for an adaptive immune response (i.e., specific antibody), the alternative
pathway for complement activation must be an important mechanism for host
defense.  Similarly, the prevalence of cells bearing high-affinity
receptors for fragments of complement proteins and the effects of
complement-receptor interactions which have already been discovered make
clear the biologic importance of these receptors.  This is a request for
continued support to study the interactions between plasma proteins of the
complement or properdin system and cells.  Two parallel lines of
investigation will be pursued.  In the first, cells (or particles
simulating cells) will be used as targets in model systems to elucidate the
mechanisms leading to activation of the alternative (properdin) pathway.
The capacity of properdin to discriminate among activators or
non-activators will be examined in studies of the kinetics and
stoichiometry of binding or purified native or activated properdin in
various microenvironments.  Antibody immunoglobulins, either murine
monoclonals specific for defined antigens on particles, or polyclonal
monomeric and polymeric IgA specific for blood group antigens, will be
examined for differential effects on classic and alternative pathway
activation, and then on interaction of the six alternative pathway factors
with defined surfaces.  In the second line of investigation the biologic
consequences of interactions between activated complement proteins or
fragments and their corresponding cell surface receptors will be examined.
Using monoclonal antibodies specific for CR1(C3b), CR2(C3d), CR3(iC3b), or
Fc receptors and bispecific hybrids of such monoclonals, receptors on human
polymophonuclear neutrophils or rat mast cells will be cross-linked and
effects on receptor display, endocytosis, oxidative metabolism, enzyme
secretion and phagocytosis examined.  The receptor on mast cells that is
specific for C3a will be studied in terms of binding characteristics and
biologic function.

## Key facts

- **NIH application ID:** 3125363
- **Project number:** 5R01AI013049-14
- **Recipient organization:** VIRGINIA COMMONWEALTH UNIVERSITY
- **SAM.gov UEI:** MLQFL4JSSAA9
- **Principal Investigator:** SHAUN RUDDY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $238,602
- **Award type:** 5
- **Project period:** 1976-05-01 → 1991-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3125363

## Citation

> US National Institutes of Health, RePORTER application 3125363, CELLULAR INTERACTIONS WITH COMPLEMENT AND PROPERDIN (5R01AI013049-14). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3125363. Licensed CC0.

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