Although all described allergenic proteinases differ, lacking structural motifs that uniquely induce Th2 and IgE responses, the role of their proteinase activity in the development of allergic sensitization has been shown for cockroach frass [7]C[8], house dust mite [9]C[10], recombinant CP virulence factor [11], and fungal allergens [12]C[13]

Although all described allergenic proteinases differ, lacking structural motifs that uniquely induce Th2 and IgE responses, the role of their proteinase activity in the development of allergic sensitization has been shown for cockroach frass [7]C[8], house dust mite [9]C[10], recombinant CP virulence factor [11], and fungal allergens [12]C[13]. in 1 ml of 0.5% saponin or 0.05% trypsin for 2 min in PBS at room temperature and incubated for 1 h with a cocktail of PE anti-IgG, and FITC anti-IgE antibodies (both from BioLegend). Cells were then washed and re-suspended for flow cytometry.(TIFF) pone.0067135.s001.tiff (3.9M) GUID:?961DBF1E-14B7-4B41-8E56-2C8CEC6F2223 Abstract The generation of long-lived antibody-secreting cells (ASC) and memory B cells are critical events for an effective vaccine and the choice of adjuvant can influence these processes. Various cellular and molecular mechanism involved in the protease action that determine Th2 responses have been identified. However, direct or indirect actions in the regulation of the induction, survival and longevity of ASC in differential compartments remain largely unknown. We investigated whether the proteolytic activity of proteins are determinant for the modulation of the memory immune response in mice, promoting the differentiation of memory Muscimol B cells to terminally differentiated end stage cells. Here, we show that the proteolytic activity of Natterins, from the venom of Brazilian fish, besides inducing a Th2 response with plasmatic titers of high-affinity antigen-specific IgE over extended periods is sufficient for the generation of signals that contribute TNFRSF11A to the formation of a survival niche in the spleen, essential for the longevity of the main subtype of ASC with B220neg phenotype. Introduction Type I IgE-mediated hypersensitivity reactions, a classical prototype Th2 polarized response, are initiated by the recognition of allergens by dendritic cells (DC), and culminate in Th2 cell differentiation, IgE antibodies (Abs) production, and mast cell sensitization and triggering. Part of the peripheral B cell compartment has undergone class switching to IgE. The class switch to IgE is a tightly regulated process that requires a Th2-biased cytokine milieu and a concerted series Muscimol of gene rearrangements and splicing events. Because long-lived antibody-secreting cells (ASC) are the source of IgE, recruitment and selection of memory B cells (Bmem) into the ASC compartment is a critical step in immune deregulation that leads to the production of IgE. Recent data [1]C[3] suggest a role of murine IgE-producing splenic memory B cell and ASC in the development and maintenance of allergies. Two B cell populations are responsible for sustaining the humoral immune memory: Bmem and ASC [4]. Memory B cells undergo rapid clonal expansion and differentiation to mount high affinity Abs Muscimol response upon exposure to antigens. ASC (positive for syndecan-1C CD138) are terminally differentiated and continue secreting high affinity antigen-specific Abs for protracted periods of time without antigenic stimulation in the bone marrow (BM) that provides a special microenvironment for their longevity [5]. Both Bmem and ASC can be generated during the first immune response from innate-like B cells as B1 and follicular and marginal conventional B (B2). Apart from their functional specialization, anatomical location, and self-renewing capacity, B1 cells can be distinguished from the more abundant B2 cells by their surface markers, because they are CD23neg, B220low, and IgMhigh [6]. A number of environmental allergens from diverse sources have proteinase activity, which has been suggested to skew the immune response toward the Th2 phenotype. Although all described allergenic proteinases differ, lacking structural motifs that uniquely induce Th2 and IgE responses, the role of their proteinase activity in the development of allergic sensitization has been shown for cockroach frass [7]C[8], house dust mite [9]C[10], recombinant CP virulence factor [11], and fungal allergens [12]C[13]. The literature on the protease derived from allergens is extensive, and its role for development of Th2 polarized responses is well established [14]. Whether proteases of venomous fish are optimal for strong and IgE Abs response has, however, not been investigated. Moreover, the direct or indirect actions of fish proateases in the regulation of the induction, survival and longevity of Ab-producing Bmem or ASC in differential compartments have not been addressed. Recently,.