Polymorphonuclear leukocytes (PMN) express a receptor of the integrin family termed complement receptor type 3 (CR3, also known as αMβ2, Mac-1, Mo1, or CD11b/CD18) that functions in several cell-cell and cell-substratum adhesion events. The capacity of CR3 to mediate adhesion may be rapidly and reversibly enhanced without changes in the number of receptors expressed on the cell surface. This thesis describes an acidic, amphiphilic lipid, termed integrin modulating factor (IMF-1), that may serve to control CR3 avidity. Addition of IMF-1 to cells or to purified CR3 causes enhanced binding of ligand. IMF-1 cannot be extracted from resting PMN but can be extracted from cells within one minute of stimulation with a variety of agonists (PMA, TNF, formylated peptides, platelet activating factor). The amount of IMF-1 extracted declines to low levels within an hour of continued stimulation. The time course of IMF-1 extraction corresponds precisely with the transient increase in the adhesive activity of CR3 observed in PMN stimulated with these agonists. IMF-1 can also increase the binding activity of another leukocyte integrin, LFA-1 (αLβ2, CD11a/CD18). However, IMF-1 does not affect the function of representative β1 and β3 integrins. IMF-1 has a molecular weight of 340 ± 16 daltons by size exclusion chromatography and appears to be distinct from the known lipid products of PMN. The data suggest that PMN control their adhesivity through a novel lipid that may act as an allosteric activator of leukocyte integrins.
","abstract_html":"<p>Polymorphonuclear leukocytes (PMN) express a receptor of the integrin family termed complement receptor type 3 (CR3, also known as α<sub>M</sub>β<sub>2</sub>, Mac-1, Mo1, or CD11b/CD18) that functions in several cell-cell and cell-substratum adhesion events. The capacity of CR3 to mediate adhesion may be rapidly and reversibly enhanced without changes in the number of receptors expressed on the cell surface. This thesis describes an acidic, amphiphilic lipid, termed integrin modulating factor (IMF-1), that may serve to control CR3 avidity. Addition of IMF-1 to cells or to purified CR3 causes enhanced binding of ligand. IMF-1 cannot be extracted from resting PMN but can be extracted from cells within one minute of stimulation with a variety of agonists (PMA, TNF, formylated peptides, platelet activating factor). The amount of IMF-1 extracted declines to low levels within an hour of continued stimulation. The time course of IMF-1 extraction corresponds precisely with the transient increase in the adhesive activity of CR3 observed in PMN stimulated with these agonists. IMF-1 can also increase the binding activity of another leukocyte integrin, LFA-1 (α<sub>L</sub>β<sub>2</sub>, CD11a/CD18). However, IMF-1 does not affect the function of representative β<sub>1</sub> and β<sub>3</sub> integrins. IMF-1 has a molecular weight of 340 ± 16 daltons by size exclusion chromatography and appears to be distinct from the known lipid products of PMN. The data suggest that PMN control their adhesivity through a novel lipid that may act as an allosteric activator of leukocyte integrins.</p>","abstract_has_math":false,"creators":["Hermanowski-Vosatka, Anne"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Samuel Wright"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1991,"date_issued":"1991-01-01T08:00:00Z","date_published":"1991-01-01T08:00:00Z","updated_at":"2026-07-24T04:11:05Z","subjects":["integrins","leukocyte adhesion","CR3","lipid signaling","IMF-1","polymorphonuclear cells","Life Sciences"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/622","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Samuel Wright"]},{"key":"dc:creator","label":"Author","values":["Hermanowski-Vosatka, Anne"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["integrins","leukocyte adhesion","CR3","lipid signaling","IMF-1","polymorphonuclear cells","Life Sciences"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/622"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Polymorphonuclear leukocytes (PMN) express a receptor of the integrin family termed complement receptor type 3 (CR3, also known as αMβ2, Mac-1, Mo1, or CD11b/CD18) that functions in several cell-cell and cell-substratum adhesion events. The capacity of CR3 to mediate adhesion may be rapidly and reversibly enhanced without changes in the number of receptors expressed on the cell surface. This thesis describes an acidic, amphiphilic lipid, termed integrin modulating factor (IMF-1), that may serve to control CR3 avidity. Addition of IMF-1 to cells or to purified CR3 causes enhanced binding of ligand. IMF-1 cannot be extracted from resting PMN but can be extracted from cells within one minute of stimulation with a variety of agonists (PMA, TNF, formylated peptides, platelet activating factor). The amount of IMF-1 extracted declines to low levels within an hour of continued stimulation. The time course of IMF-1 extraction corresponds precisely with the transient increase in the adhesive activity of CR3 observed in PMN stimulated with these agonists. IMF-1 can also increase the binding activity of another leukocyte integrin, LFA-1 (αLβ2, CD11a/CD18). However, IMF-1 does not affect the function of representative β1 and β3 integrins. IMF-1 has a molecular weight of 340 ± 16 daltons by size exclusion chromatography and appears to be distinct from the known lipid products of PMN. The data suggest that PMN control their adhesivity through a novel lipid that may act as an allosteric activator of leukocyte integrins.
"]},{"key":"dc:title","label":"Title","values":["Integrin Modulating Factor 1 (IMF-1): A lipid that modulates leukocyte integrins"]}]}],"canonical_facts":{"dc:contributor":["Samuel Wright"],"dc:creator":["Hermanowski-Vosatka, Anne"],"dc:description.abstract":["Polymorphonuclear leukocytes (PMN) express a receptor of the integrin family termed complement receptor type 3 (CR3, also known as αMβ2, Mac-1, Mo1, or CD11b/CD18) that functions in several cell-cell and cell-substratum adhesion events. The capacity of CR3 to mediate adhesion may be rapidly and reversibly enhanced without changes in the number of receptors expressed on the cell surface. This thesis describes an acidic, amphiphilic lipid, termed integrin modulating factor (IMF-1), that may serve to control CR3 avidity. Addition of IMF-1 to cells or to purified CR3 causes enhanced binding of ligand. IMF-1 cannot be extracted from resting PMN but can be extracted from cells within one minute of stimulation with a variety of agonists (PMA, TNF, formylated peptides, platelet activating factor). The amount of IMF-1 extracted declines to low levels within an hour of continued stimulation. The time course of IMF-1 extraction corresponds precisely with the transient increase in the adhesive activity of CR3 observed in PMN stimulated with these agonists. IMF-1 can also increase the binding activity of another leukocyte integrin, LFA-1 (αLβ2, CD11a/CD18). However, IMF-1 does not affect the function of representative β1 and β3 integrins. IMF-1 has a molecular weight of 340 ± 16 daltons by size exclusion chromatography and appears to be distinct from the known lipid products of PMN. The data suggest that PMN control their adhesivity through a novel lipid that may act as an allosteric activator of leukocyte integrins.
"],"dc:identifier":["https://digitalcommons.rockefeller.edu/student_theses_and_dissertations/622"],"dc:subject":["integrins","leukocyte adhesion","CR3","lipid signaling","IMF-1","polymorphonuclear cells","Life Sciences"],"dc:title":["Integrin Modulating Factor 1 (IMF-1): A lipid that modulates leukocyte integrins"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T04:11:05Z"}