# CELL SUBPOPULATIONS IN TRANSPLANTATION IMMUNITY

> **NIH NIH R01** · DANA-FARBER CANCER INST · 1991 · $213,989

## Abstract

After a lymphocyte recognizes antigen on the surface of a
somatic cell or on an "antigen presenting cell", an efficient
immune response depends on attraction of other immunological
cells to the site of recognition.  Immunectin secretion is a likely
candidate for such an attractant.  It is rapidly and abundantly
transcribed and secreted after activation of T-lymphocytes and
Thy+ NK cell clones but not B cells, mast cell clones or
fibroblasts.  The recombinant molecule is released into the
supernatant after expression of the cDNA is COS cells and this is
consistent with the molecule having the structural features of a
secreted protein.  Immunectin is extremely hydrophilic and has a
single N-linked glycosylation site.  Immunectin contains the
tripeptide sequence ARg-Gly-Asp (RGD), which marks a family of
extracellular adhesives and causes specific cell types to migrate
and express new genes.  In all case studies, the RGD tripeptide is
a critical part of the molecule's binding site to target cell.
Immunectin is no exception.  Mast cells and macrophages carry
about 105 immunectin receptors which bind to the ligand with a
Kd of 10-12.  Binding results in migration of cells across an
immunectin gradient towards the source of immunectin
production.  The hydrophilic nature of recombinant immunectin
makes it unlikely that a gradient formed around an activated T-
cell in vivo would be disturbed by non-specific interaction with
hydrophobic molecules or cells.  Moreover, studies of monocytes
that migrate in an immunectin gradient show that binding to
immunectin at appropriate concentrations activates them to
become phagocytic and express surface IA molecules.  Taken
together, this evidence indicates that immunectin production by
T-cells after activation by foreign antigen to be responsible for
recruitment of immunologic effector cells including mast cells
and macrophages to the site of activation.

In summary, the immune response triggered by recirculating
lymphocytes is marked by the secretion of large amounts of
immunectin which binds with high affinity to immunologic
effector cells.  We will define the role of immunectin in
inflammatory and allergic immune responses in vitro and in
animals, and further characterize the structural basis of
immunectin activity.

## Key facts

- **NIH application ID:** 3125125
- **Project number:** 5R01AI012184-16
- **Recipient organization:** DANA-FARBER CANCER INST
- **SAM.gov UEI:** DPMGH9MG1X67
- **Principal Investigator:** HARVEY CANTOR
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1991
- **Award amount:** $213,989
- **Award type:** 5
- **Project period:** 1977-07-01 → 1991-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3125125

## Citation

> US National Institutes of Health, RePORTER application 3125125, CELL SUBPOPULATIONS IN TRANSPLANTATION IMMUNITY (5R01AI012184-16). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3125125. Licensed CC0.

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