The stimulation of T cells with anti-CD2 monoclonal antibodies facilitates the induction of polyclonal B-cell responses but does not enhance the activation of antigen-specific B cells.
In this report we compare the effect of stimulation of peripheral mononuclear cells (PBMC) by using two monoclonal antibodies (MoAb) directed against the CD2 receptor on T cells or by using autologous erythrocytes (E) which express on their surface lymphocyte function-associated antigen 3 (LFA3), a natural ligand for CD2. The addition of autologous erythrocytes to pokeweed mitogen (PWM)-stimulated PBMC results in the enhancement of polyclonal immunoglobulin synthesis and of antigen-specific B-cell responses. Because B cells lack the CD2 molecule, it can be concluded that their enhanced activity is a consequence of the delivery of activating signals by activated T lymphocytes. When PBMC cultures were stimulated with a pair of anti-CD2 MoAb (Leu5b and VIT13) we were able to induce polyclonal immunoglobulin synthesis, particularly IgM, in cultures supplemented with interleukin 2(IL-2). Specific responses to tetanus toxoid (TT) and keyhole limpet haemocyanin (KLH) were also enhanced by the addition of autologous E to PWM-stimulated PBMC. Significant anti-TT responses were observed in cultures stimulated with E + TT + IL-2. In contrast, stimulation of PBMC with VIT13 + Leu5b + IL-2 + antigen was not effective in inducing anti-TT antibody and only weakly effective in inducing anti-KLH antibodies. Replacing Leu5b by anti-CD3 had no effect on the induction of specific antibody responses; in contrast, replacement of Leu5b by E enhanced anti-TT antibody production while the effect on polyclonal production of IgM was minimal. Therefore, it appears that the signal delivered by the association of CD2 with LFA3 is a better potentiating signal for specific B-cell responses than the signal delivered by pairs of MoAb to different epitopes of CD2 or to CD2 and CD3 epitopes.
Department of Microbiology and Immunology, Medical University of South Carolina, Charleston 29425.
R
R
Trifiletti
B
B
Hyman
M
M
LaVia
W
W
Knapp
G
G
Virella
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D018801:CD2 Antigens; D018968:CD58 Antigens; D002478:Cells, Cultured; D004912:Erythrocytes / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D018801:CD2 Antigens; D018968:CD58 Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D011043:Pokeweed Mitogens; D011971:Receptors, Immunologic; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin