title: Engagement of CD14 on human monocytes terminates T cell proliferation by delivering a negative signal to T cells.
abstract: We have recently shown that engagement of the human monocytic Ag CD14 by murine mAb induces lymphocyte function-associated antigen-1/intercellular adhesion molecule-1-dependent homotypic adhesion. To determine whether CD14 plays a role in monocyte-T cell interactions, we tested the effect of anti-CD14 mAb on the proliferation of human T cells. Our results show that anti-CD14 mAb strongly inhibited T cell proliferation induced by Ag, anti-CD3 mAb, and mitogenic lectins. Inhibition by anti-CD14 mAb was epitope-dependent and required physical contact between monocytes and T cells. CD14 engagement did not affect IL-2R expression or IL-2 synthesis but induced a state of unresponsiveness that was not IL-2 specific; proliferation of anti-CD3-activated T cell blasts in response to both IL-2 and IL-4 was abrogated by addition of monocytes preincubated with anti-CD14 mAb. Inhibition of T cell proliferation after engagement of CD14 on monocytes was likely to result from delivery of a negative signal to T cells, rather than from disruption of a costimulatory monocyte-derived signal, because incubation of monocytes with anti-CD14 mAb also inhibited monocyte-independent T cell proliferation induced by PMA and ionophore. These results, together, point to a role of CD14 in the monocyte-dependent regulation of T cell proliferation.
authors.affiliation: Children's Hospital/Department of Pediatrics, Harvard Medical School, Boston, MA 02115.
authors.forename: K H
authors.initials: KH
authors.lastname: Lue
authors.forename: R P
authors.initials: RP
authors.lastname: Lauener
authors.forename: R J
authors.initials: RJ
authors.lastname: Winchester
authors.forename: R S
authors.initials: RS
authors.lastname: Geha
authors.forename: D
authors.initials: D
authors.lastname: Vercelli
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D015703:Antigens, CD / Q000276:immunology / Q000502:physiology*; D015214:Antigens, Differentiation, Myelomonocytic / Q000502:physiology*; D002450:Cell Communication; D002455:Cell Division / Q000187:drug effects; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors; D008213:Lymphocyte Activation; D051379:Mice; D009000:Monocytes / Q000502:physiology*; D015375:Receptors, Interleukin-2 / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D007376:Interleukin-2; D018950:Lipopolysaccharide Receptors; D015375:Receptors, Interleukin-2; D015847:Interleukin-4