# STRUCTURE AND POLYMORPHISMS OF THE HUMAN C3B RECEPTOR

> **NIH NIH R01** · BRIGHAM AND WOMEN'S HOSPITAL · 1990 · $42,911

## Abstract

The objectives are to define the complete structure of the human receptor
for complement fragments C3b/C4b and its functional role in immune and
inflammatory reactions.  The human C3b/C4b receptor (CR1) is a polymorphic
glycoprotein that ranges in size from Mr 160,000 to 250,000 when analyzed
by SDS-PAGE and these allelic forms are inherited in an autosomal
codominant manner.  The receptor is found in soluble form in plasma and on
the surface of erythrocytes, neutrophils, monoctyes, lymphocytes and
glomerular podocytes.  The functional capabilities of CR1 include
regulation of the amplification C3 convertase, and the removal of
complement coated targets and immune complexes by phagocytic and endocytic
reactions.  The number of CR1 molecules on erythrocytes is also geneticaly
controlled and varies by 10 fold among normal individuals.  Inherited as
well as acquired deficiencies of CR1 on several cell types have been
documented in patients with systemic lupus erythematosus.  In order to
understand the overall structure and function of human CR1, we propose to
1) Isolate and study the structure of the gene which codes for human CR1,
2) Identify the sites of polymorphisms on the CR1 gene and, 3) Define the
functional domains within the CR1 gene.  The recent identification of a
partial cDNA clone for human CR1 enables us to isolate recombinant genomic
clones and identify restriction length polymorphisms in the human CR1
gene.  The basis of the structural polymorphisms will be elucidated by
isolation and comparisons of the different alleles and the different
domains of CR1 will be mapped by studying the functional capacities of
deletion mutants after transfection into CR1 recipient cells.  The results
of these studies will not only facilitiate the understanding of the
regulation of CR1 and the basis of its abnormalities in rheumatic diseases,
but also provide insight into the evolution of the allelic forms of CR1,
and its functional correlates in plasma, factor H and C4 binding protein.

## Key facts

- **NIH application ID:** 3158122
- **Project number:** 5R01AR037408-05
- **Recipient organization:** BRIGHAM AND WOMEN'S HOSPITAL
- **SAM.gov UEI:** QN6MS4VN7BD1
- **Principal Investigator:** WINNIE W WONG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $42,911
- **Award type:** 5
- **Project period:** 1986-07-01 → 1990-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3158122

## Citation

> US National Institutes of Health, RePORTER application 3158122, STRUCTURE AND POLYMORPHISMS OF THE HUMAN C3B RECEPTOR (5R01AR037408-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3158122. Licensed CC0.

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