Lymphocyte-antigen-presenting cell interactions

Inhibit the interaction between antigen or antigen-presenting cells (AJPCs) and T-lymphocytes... 

Inhibitors of Interaction between Antigen or Antigen-Presenting Cells and T-Lymphocytes... 

The class II proteins are produced mainly within specific cells, known as antigen-presenting cells (APC). Their role is to prepare antigens derived from the pathogens in such a way that they can interact with the T-helper cell receptor. Since this is their only role, they are sometimes called professional antigen-presenting cells , i.e. other immune cells can also present peptides to T-helper cells (e.g. macrophages, B-lymphocytes) but this is not their prime role. The professional APCs are also known as dendritic cells. 

Helper T Lymphocytes (CD4) recognize viral or bacterial antigens together with MHC class II molecules on surface of antigen presenting cell, such as a macrophage. Interaction leads to cytokine secretion, initiating a cascade of iimnune reactions. 

Muromonab is a mouse monoclonal antibody against the CD3 receptor of T-lymphocytes. Its activity is based on inhibition of interactions between antigen-presenting cells and T-cells. By preventing antigen presentation it suppresses T-cell activation and proliferation. The indication for muromonab is the treatment of acute graft rejection after kidney, liver and hart transplantations. Its adverse effects consist of those symptoms that are initiated by the release of cytokines and lymphokines as a result of the reaction of muromonab with CD3 positive T-lymphocytes. These symptoms may vary from a mild flu-like syndrome to serious cardiac, pulmonale and neurological reactions. 

Figure 6.30 General mechanism of interaction of drug metabolite or breakdown product (hapten) with protein and production of antibodies, which recognize the subsequent antigen produced in the APC. T-cells and B-cells are types of lymphocytes. Abbreviation APC, antigen presenting cell.

In adult mice the primary antibody response to sheep red blood cells (SRBC) is one of the most sensitive and reproducible immune endpoints that is affected by TCDD and related HAHs. For example, the TCDD dose that suppresses this response by 50% in mice is approximately 0.7 pg TCDD/kg. The antibody response to SRBCs is dependent on the collaborative interaction of antigen-presenting cells (dendritic cells) and T and B lymphocytes all of these cells appear to be targets for TCDD. 

Differentiation of lymphocytes produces cells with different functions, such as B cells, and T helper and killer cells. The former produce and secrete antibodies, releasing them into Ijrmph and blood, the latter are responsible for the cellular immune response. The response of T cells is antigen-spedfic, just like the response of B cells. But, T cells interact with another cell in the body, the antigen-presenting cells (APCs), which have taken up and processed the foreign antigen. Helper T cells react with APCs and killer T cells... 

T lymphocytes, thymus-derived lymphocytes or T cells are formed in the thymus. They carry out immune reactions involving cell-cell interactions and are responsible for cell-mediated immunity. One distinguishes specific and non-specific cytotoxic killer T cells, (NK cells, natural killer cells), and helper T cells which cooperate with antigen-presenting cells, APC s, in the initiation of an immune response. Suppressor T cells dampen the action of helper T cells. 

Lymphoid Tissue Equivalent (LTE) module an artificial lymph node, where generated antigen-presenting cells (APCs) efficiently interact with T and B lymphocytes to initiate antigen-specific immune responses... 

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