Human monocyte-derived soluble product(s) has an accessory function in the generation of histamine- and concanavalin

We have analyzed the cellular interactions required for the generation of histamine- and concanavalin A (Con A)-induced suppressor T cells by employing a co-culture assay and techniques for fractionation of human blood mononuclear cells (PBMC). PBMC cultured in the presence of histamine (0.1 mM-1 mM) or Con A (20 micrograms/ml) for 24 h, mitomycin treated and subsequently combined with autologous mitogen-stimulated mononuclear cells, significantly suppressed a subsequent blastogenic response. PBMC fractionated over nylon wool columns and depleted of adherent cells and enriched for T cells (NWNA-T) were unable to generate suppressor activity. However, suppressor cell function by NWNA-T cells was reconstituted by the addition of autologous monocytes. In both the histamine and ConA suppressor systems, the requirement for monocytes in the activation process was enhanced by suspending the NWNA-T population in supernatants derived from allogeneic monocytes stimulated with heat-killed Staphylococcus albus. These crude supernatants contained leukocytic pyrogen (LP) and lymphocyte activating factor (LAF). Sequential purification and separation of the crude supernatants using gel-filtration, immunoadsorption, and isoelectric focusing demonstrated that only those fractions containing LP and LAF were capable to reconstituting NWNA-T cell histamine and Con A-induced suppressor activity. Thus, these studies suggest that the accessory role of supernatants derived from activated monocytes in the generation of suppressor cells may be mediated by LP/LAF. Further studies are in progress to explore the mechanism by which soluble factors stimulate suppressor T cells.

Related Concept Videos

Cell-mediated Immune Responses01:40

Cell-mediated Immune Responses

Overview
Differentiation of Common Myeloid Progenitor Cells01:15

Differentiation of Common Myeloid Progenitor Cells

Common myeloid progenitors (CMPs) are oligopotent cells that can differentiate into granulocytes and macrophages. Granulocytes and macrophages are essential for protecting the body against bacterial, viral, or fungal infections. They migrate from the bone marrow into the circulating blood to reach specific tissue sites where they differentiate and help in immune surveillance. However, they survive only for a few days and must be continuously made available to the organism to maintain a robust...
Antigens Involved in Adaptive Immunity01:26

Antigens Involved in Adaptive Immunity

An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
T Cell Activation and Clonal Selection01:22

T Cell Activation and Clonal Selection

T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
T Cell Types and Functions01:24

T Cell Types and Functions

When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
B Cell Activation and Differentiation01:24

B Cell Activation and Differentiation

The adaptive immune response, a sophisticated defense mechanism, relies on the activation and differentiation of B lymphocytes, or B cells. These processes enable our bodies to mount a tailored response against specific pathogens such as bacteria, free virus particles, toxins, and parasites.
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...