Depression by Fc gamma receptor ligands of SRBC-induced IgM-PFC generation in human blood mononuclear cell cultures.
A tissue-culture system to stimulate human peripheral blood mononuclear cells (PBMC) has been employed in which IgM plaque-forming cell (IgM PFC) generation in response to sheep erythrocytes (SRBC) is dependent on macrophages and T suppressor and helper lymphocytes. In this system PBMC from normal subjects give IgM PFC responses ranging from 26 to 938 PFC/culture. Heat-aggregated human IgG or immune complexes present for the duration of culture induce a significant depression of PFC. Unaggregated IgG has no effect on the response or only a moderate stimulatory effect at the highest dose. The results of these experiments are compatible with previous results in a murine system, which indicated that Fc gamma receptor-positive (Fc gamma R+) cells in the suppressor subset are the target for aggregated IgG and induce depression of the PFC response. A similar mechanism may be operating in the human system described here, although the target cell has not been identified. These results may reflect a mechanism of immunomodulation dependent on interaction of Fc receptor (FcR) ligands with FcR, which may play a role in the pathogenesis of immune complex disorders.
Gabrielli
A
A
Department of Pathology, Medical University of South Carolina, Charleston 29425.
Silver
R
R
Teti
G
G
Chiofalo
M S
MS
Misefari
A
A
Venza-Teti
D
D
Virella
G
G
La Via
M F
MF
D000921:Antibody-Producing Cells / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000276:immunology; D000943:Antigens, Differentiation / Q000494:pharmacology*; D002478:Cells, Cultured; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D011961:Receptors, Fc / Q000494:pharmacology*; D017452:Receptors, IgG; D010948:Viral Plaque Assay
D000936:Antigen-Antibody Complex; D000943:Antigens, Differentiation; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011961:Receptors, Fc; D017452:Receptors, IgG