Role of monocytes in anti-CD3-induced T-cell DNA synthesis: effect of chloroquine and monensin on anti-CD3-induced human T-cell activation.
Anti-CD3 monoclonal antibody (MoAb) induces proliferation of freshly isolated peripheral blood T cells only in the presence of monocytes/macrophages and requires binding of the Fc portion of antibody to monocytes/macrophages. In this investigation, we examined whether monocytes process anti-CD3 similar to any soluble antigen and present to T cells in context with HLA-DR to induce maximal DNA synthesis. Adherent monocytes were pulsed with anti-CD3 MoAb in the presence or absence of the lysozomotropic agents chloroquine and monensin, which are known to inhibit processing of soluble antigens, washed extensively, and then incubated with autologous T cells in the absence of soluble anti-CD3, and 3H-thymidine incorporation and CD25 expression were measured. Both monensin and chloroquine inhibited anti-CD3-pulsed monocyte-induced T-cell DNA synthesis and CD25 expression in a dose-dependent manner. This inhibitory effect was not due to any loss in cell viability or the effect on the expression of HLA-DR on monocytes. Paraformaldehyde-fixed monocytes pulsed with anti-CD3 MoAb induced significantly less DNA synthesis, HLA-DR expression, and CD25 antigen expression on autologous T cells as compared to responses induced by unfixed anti-CD3-pulsed monocytes. The treatment of anti-CD3-pulsed monocytes with framework-specific anti-HLA-DR MoAb inhibited their capacity to induce T-cell DNA synthesis. These data suggest that monocytes, in addition to serving as the matrix for cross-linking, also process anti-CD3 MoAb and present to the T cells in the context of HLA-DR antigens to induce optimal DNA synthesis.
Vayuvegula
B
B
Division of Basic and Clinical Immunology, University of California, Irvine 92717.
Ohira
K
K
Gollapudi
S
S
Gupta
S
S
D000911:Antibodies, Monoclonal / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D017252:CD3 Complex; D002469:Cell Separation; D002738:Chloroquine; D004247:DNA / Q000096:biosynthesis*; D006684:HLA-DR Antigens / Q000096:biosynthesis; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008985:Monensin; D009000:Monocytes / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D002738:Chloroquine; D004247:DNA; D008985:Monensin