Faculty Collaboration Database

Aggregated immunoglobulin protects immune T cells from suppression: dependence on isotype, Fc portion, and macrophage FcgammaR. Scand J Immunol 1998 Feb;47(2):136-45

Date

03/13/1998

Pubmed ID

9496689

DOI

10.1046/j.1365-3083.1998.00264.x

Scopus ID

2-s2.0-0031939417 (requires institutional sign-in at Scopus site)   13 Citations

Abstract

We determined the regulatory properties of heat-aggregated immunoglobulins (HA-Ig) that possess many activities of immune complexes (IC), such as binding and activation of cells via immunoglobulin Fc gamma receptors (FcgammaR). HA-Ig protected contact sensitivity (CS) effector T cells from antigen-specific immunosuppression, while monomeric IgG were inactive. This anti-suppressive activity of HA-Ig was antigen non-specific, and depended on the species from which Ig was derived, i.e. mouse and rat HA-Ig were protective in mice, and of other species were inactive. The protecting activity of HA-Ig was confined to IgG2a and IgG3, and to a lesser degree to IgG1 isotypes, and resided in the Fc domain. Removal of phagocytic cells from the CS-immune target cells, or blocking with anti-FcgammaR mAb, abolished HA-Ig protection of CS-effector T cells from suppression. We suggest that HA-Ig multimers acted via Fc domains, in one of two ways: by binding to FcgammaR of macrophages to produce positive-acting cytokines, or by blocking FcgammaR on macrophages, to compete with suppressive factors that can also bind to FcgammaR. If HA-Ig protection of T cells is generalized, it is likely that IC in vivo may non-specifically overcome suppression of responses to antigen that normally are under the control of T suppressive cells, and thus may contribute to the development of autoimmunity.

Author List

Ptak W, Paliwal V, Bryniarski K, Ptak M, Askenase PW

Author

Vipin Paliwal PhD Associate Professor in the Physics & Chemistry department at Milwaukee School of Engineering

MESH terms used to index this publication - Major topics in bold

Animals
Heating
Immunoglobulin Fc Fragments
Immunoglobulin G
Immunoglobulin Isotypes
Macrophages, Peritoneal
Male
Mice
Mice, Inbred CBA
Phagocytes
Rabbits
Rats
Receptors, Fc
Spleen
T-Lymphocytes
T-Lymphocytes, Regulatory
Tumor Cells, Cultured