Dominique Juy

In vivo regulation of humoral and cellular immune reponses of mice by a synthetic adjuvant, N-acetyl-muramyl-l-alanyl-d-isoglutamine, muramyl dipeptide for MDP

Abstract In vitro immunizations by T-dependent or T-independent antigens can be modulated by muramyl dipeptide (MDP). Enhancement or suppression of the antibody responses was observed according to the spleen-cell concentrations. Data presented here show that MDP can also suppress the immune response in vivo if used at relatively high dosage and injected before the antigen (SRBC). In vitro generation of cytotoxic T-lymphocyte recovered from mice which had been treated by MDP under the same experimental conditions was also decreased whereas macrophage cytostatic activity was not affected. By MDP pretreatment, a significant increase of antibody-dependent cell-mediated cytotoxicity was observed.

Inhibitory and stimulatory effects of a synthetic glycopeptide (MDP) on the in vitro PFC response: Factors affecting the response

Abstract A synthetic adjuvant active glycopeptide, N -acetyl-muramyl- l -alanyl- d -isoglutamine (MDP), has been previously shown to enhance the in vitro immune response of mouse spleen cells to T-dependent or independent antigens. Data presented here show that the net activity of MDP on the in vitro immune response is closely related to the cell culture conditions: Two distinct patterns of MDP activities could actually be detected. Marked stimulation of the PFC response was observed at “low density” cell cultures. In contrast, suppression could be seen at “high density” cell cultures. Moreover, the culture conditions which permitted characterization of either the enhancement or suppression of the immune response by MDP were strongly dependent on the strain of mouse used. However, these activities were not dependent on antigen concentration, on kinetics of responses, or on cytotoxic effects.

[14] Rosette-forming cell assay for detection of antibody-synthesizing hybridomas

Publisher Summary This chapter describes rosette-forming cell assay for the detection of antibody-synthesizing hybridomas. Detection of antibody-synthesizing hybridomas represents a difficult problem and is always a tedious work. The assay required for that screening should be highly specific, fast, and sensitive enough to allow an extremely selective screening of several hundred clones growing simultaneously. The rosette-forming cell micromethod is the method of choice when the antigen can be coupled to erythrocytes. This assay can be successfully used for the screening of many different hybridomas, such as antiDNP, antidextran, antilevan, anti-idiotype, and antienzymes clones. The rosette assay may also be useful for the precise analysis of the specificity of the monoclonal antibody secreted by hybridoma cells. The chapter presents an example of the analysis of cross-reactive idiotypes by means of monoclonal antibodies and the rosette assay.

A new rapid rosette-forming cell micromethod for the detection of antibody-synthesizing hybridomas.

The method reported here describes a microrosetting assay which allows the early detection of antibody-synthesizing hybridomas. This method is specific, requires very few hybridoma cells and avoids artifacts resulting from the presence of antibodies secreted by spleen cells in the primary hybridoma cultures. It is easy to perform and allows the screening of more than one hundred independent clones within a few hours.

Murine anti-TNP antibodies positive for either λ1 OR λ2 light chains express common idiotypic determinants

Abstract Although the lambda-bearing antibodies represent only 5% of the total mouse serum immunoglobulins, some antigens such as B1355 dextran (α(1–3)Dex), the 4-hydroxy-3-nitrophenyl acetyl (NP) and 2,4-dinitro or 2,4,6-trinitrophenyl (DNP/TNP) antigens can induce lambda-positive immune responses. In contrast to the lambda antibody response against α(1–3)Dex and NP antigens which is restricted to the λ1 isotype it was shown that the response to the DNP (or TNP) antigen uses λ1and λ2 and λ3 isotypes. The idiotypy of the α(1–3)Dex and NP systems has been well characterized contrary to that of the lambda-positive anti-TNP/DNP response which has been poorly studied. In this paper, we describe two idiotopes (Id C19-3 and Id D1 1–2) shared by two BALB/c monoclonal anti-TNP antibodies (TNP5 and TNP9) which, respectively, use the λ1 and λ2 light chains. These idiotopes were independently expressed on other monoclonal anti-TNP/DNP antibodies and appear to require the use of a unique V H gene associated with a particular V λ region. After TNP-Ficoll immunization, BALB/c mice recurrently express both idiotopes on λ1 and (λ2+λ3) anti-TNP antibodies. In addition, all the mouse strains immunized against TNP-Ficoll give a λ1- and (λ2 + λ3)-positive immune response with the exception of SJL and SJA strains which present a deficit for the expression of λ1 light chain. The expression of Id C19-3 was restricted to the strains with the Igh-V a allotypic haplotype (including SJA) whereas the Id D11-2 was extensively expressed in the various strains.

Frequency analysis of human peripheral blood B cells sensitive to CD2 monoclonal antibody-activated T cells

Recent studies have demonstrated that appropriate pairs of cluster of differentiation 2 (CD2) monoclonal antibodies (MoAbs) directed against two epitopes on the T11 molecule induced human T-cell activation leading to the production of several lymphokines. Here we report that human peripheral blood B lymphocytes cultured in the presence of the CD2 (D66 + T11) MoAb, together with T lymphocytes and monocytes, secreted larger amount of immunoglobulin (Ig) than when they were incubated in the same culture conditions in the presence of pokeweed mitogen (PWM). We further show that the level of Ig secreted by the progeny of a single responsive B cell is similar in both systems and demonstrate that the increase in the Ig concentration is directly related to the high frequency of B-cell precursors sensitive to CD2 MoAb-activated T cells.

Enhancement of lymphocyte dependent antibody cytotoxicity by anti allotype serum

Abstract Anti-allotype b4 and anti-allotype a3 antibody as well as heterologous anti-rabbit IgG enhanced the lymphocyte-dependent antibody cytotoxicity, in a system using chicken red blood cells (ChRBC) coated with rabbit anti-ChRBC antibody ( a 3 a 3 , b 4 b 5 ) as target cells and rabbit lymphocytes ( a 3 a 3 , b 4 b 5 ). No enhancement was observed with anti-allotype b6 antiserum, nor with heterologous anti-rabbit IgM, IgA, and Fc antibodies. Cytotoxicity mediated by spleen, bone marrow, and thymus lymphocytes was enhanced by anti-allotype antibody. The enhancement of cytotoxicity by anti-allotype antibody cannot be attributed to lymphocyte proliferation but is more likely related to the formation of an additional bridge between effector cell and target cell.

ORIGIN OF EFFECTOR CELLS AND MECHANISM OF LYMPHOCYTE-DEPENDENT ANTIBODY CYTOTOXICITY IN RABBIT

Publisher Summary This chapter discusses that lymphocyte-dependent antibody (LDA) cytotoxicity requires the presence of intact IgG molecule of anti-target antibody, which interacts with Fc receptor of the effector cells by its Fc portion. In the rabbit, the cell that mediates LDA cytotoxicity can be found in central lymphoid organs such as thymus and bone marrow as well as in peripheral lymphoid organs such as the spleen. The chapter discusses the characterization of a bridge or bridges between various receptors of effector and target cells in terms of lymphocyte-dependent antibody cytotoxicity. It describes the influence of heterologous anti-rabbit isotypic antibodies on LDA cytotoxicity of rabbit lymphocytes against ChRBC, coated with rabbit antitarget antibodies. The enhancement induced by antiallotype antibodies is an immunological phenomenon. The bridge formed by activated C3—between target cells coated with anti-Forssman antibody and the C3 receptor of effector cells—cannot induce hemolysis. Only the bridge established between IgG molecules of antibodies coating the target cells and the Fc or IgG receptors of effector cell could mediate the LDA cytotoxicity.