Increased levels of soluble low-affinity Fc gamma receptors (IgG-binding factors) in the sera of tumour-bearing mice.
Soluble forms of low affinity Fc gamma receptors (Fc gamma R), also called IgG-binding factors (IgG-BF), have been shown to play a regulatory role in immune responses. By using an immunodot assay with the anti-mouse Fc gamma R MoAb, 2.4G2, the levels of IgG-BF have been measured in the sera of mice bearing syngeneic tumours of lymphoid or non-lymphoid origin or in mice injected with high doses of murine IgG. These sera contained large amounts of IgG-BF as compared with controls. In the case of mice bearing IgG2a- or IgG2b-secreting hybridomas or lymphomas, serum IgG-BF increased progressively with tumour size and serum monoclonal IgG concentration, reaching 4-12 times the normal levels. A less than three-fold increase was found in mice bearing an IgG1-secreting hybridoma or tumours which do not secrete IgG (IgA-secreting hybridoma, non-immunoglobulin-secreting lymphoid tumours or melanoma) or in mice injected with 9 mg of monoclonal IgG2a. The enhancement of serum IgG-BF levels was independent of the expression of Fc gamma R by the tumour cells, suggesting that the majority of IgG-BF secreted in response to tumours was produced by the host rather than by the tumour. The increased production of IgG-BF may participate in the control of tumour growth and in the modulation of the host immune responses in tumour-bearing animals.
Lynch
A
A
INSERM U.255, Institut Curie, Paris, France.
Tartour
E
E
Teillaud
J L
JL
Asselain
B
B
Fridman
W H
WH
Sautès
C
C
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000943:Antigens, Differentiation / Q000737:chemistry / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism*; D008222:Lymphokines / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D009374:Neoplasms, Experimental / Q000097:blood / Q000276:immunology*; D029584:Prostatic Secretory Proteins; D011961:Receptors, Fc / Q000737:chemistry / Q000378:metabolism*; D017452:Receptors, IgG; D012995:Solubility
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D007074:Immunoglobulin G; D008222:Lymphokines; D029584:Prostatic Secretory Proteins; D011961:Receptors, Fc; D017452:Receptors, IgG; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors