Nasal Cholera Toxin Elicits IL-5 and IL-5 Receptor α-Chain Expressing B-1a B Cells for Innate Mucosal IgA Antibody Responses

Abstract

In this study, we examine whether native cholera toxin (nCT) as a mucosal adjuvant can support trinitrophenyl (TNP)-LPS-specific mucosal immune responses. C57BL/6 mice were given nasal TNP-LPS in the presence or absence of nCT. Five days later, significantly higher levels of TNP-specific mucosal IgA Ab responses were induced in the nasal washes, saliva, and plasma of mice given nCT plus TNP-LPS than in those given TNP-LPS alone. High numbers of TNP-specific IgA Ab-forming cells were also detected in mucosal tissues such as the nasal passages (NPs), the submandibular glands (SMGs), and nasopharyngeal-associated lymphoreticular tissue of mice given nCT. Flow cytometric analysis showed that higher numbers of surface IgA+, CD5+ B cells (B-1a B cells) in SMGs and NPs of mice given nasal TNP-LPS plus nCT than in those given TNP-LPS alone. Furthermore, increased levels of IL-5R α-chain were expressed by B-1a B cells in SMGs and NPs of mice given nasal TNP-LPS plus nCT. Thus, CD4+ T cells from these mucosal effector lymphoid tissues produce high levels of IL-5 at both protein and mRNA levels. When mice were treated with anti-IL-5 mAb, significant reductions in TNP-specific mucosal IgA Ab responses were noted in external secretions. These findings show that nasal nCT as an adjuvant enhances mucosal immune responses to a T cell-independent Ag due to the cross-talk between IL-5Rα+ B-1a B cells and IL-5-producing CD4+ T cells in the mucosal effector lymphoid tissues.

Oral Clarithromycin Enhances Airway Immunoglobulin A (IgA) Immunity through Induction of IgA Class Switching Recombination and B-Cell-Activating Factor of the Tumor Necrosis Factor Family Molecule on Mucosal Dendritic Cells in Mice Infected with Influenza A Virus

“…At days 8 and 12 after infection, nasal washes (NWs), bronchoalveolar fluids (BALF), and plasma were collected as described previously (27,45) and subjected to enzyme-linked immunosorbent assay (ELISA) to determine anti IAV-specific S-IgA and IgG levels (27,33,39). Mononuclear cells isolated from the MeLNs, lungs, NPs, and spleen were subjected to an enzyme-linked immunosorbent spot (ELISPOT) assay to determine the numbers of IgA and IgG antibody (Ab)-forming cells (AFCs), as described previously (15,17,39).…”

“…Mononuclear cells from the mediastinal lymph nodes (MeLNs) and spleen were isolated under aseptic conditions by the mechanical dissociation method as described previously (14,17). Nasal passages (NPs) were isolated using a modification of the dissociation method described previously (14,15,17). Mononuclear cells were isolated from the lungs by a combination of an enzymatic dissociation procedure using collagenase type IV (0.5 mg/ml; Sigma-Aldrich, St. Louis, MO) followed by discontinuous Percoll (Amersham Biosciences, Piscataway, NJ) gradient centrifugation.…”

CD19+CD5+ B Cells in Primary IgA Nephropathy

“…13,35,36 The IgA antibodies produced by CD19 ϩ CD5 ϩ B cells are usually low affinity, and poly-or autoreactive. 37,38 High-affinity, pathogenic autoantibodies have been detected in patients with autoimmune diseases.…”

The Nasal Dendritic Cell-Targeting Flt3 Ligand as a Safe Adjuvant Elicits Effective Protection against Fatal Pneumococcal Pneumonia

“…In order to examine mucosal and systemic immune responses to Ag, rPspA-specific IgA and IgG antibody (Ab) levels in plasma, NWs, and BALF were determined by ELISA on day 7 after the last immunization, as described previously (18,19,32). Briefly, 96-well Falcon microtest assay plates (BD Biosciences, Oxnard, CA) were coated with 1 g/ml of rPspA in PBS.…”

“…Endpoint titers were expressed as the reciprocal log 2 of the last dilution that gave an optical density at 415 nm (OD 415 ) of 0.1 greater than the background level. Further, mononuclear cells obtained from spleen, NALT, cervical lymph nodes (CLNs), mediastinal lymph nodes (MeLNs), NPs, and lungs were subjected to an enzyme-linked immunospot (ELISPOT) assay in order to determine the numbers of Ag-specific Ab-forming cells (AFCs) (18,19). In brief, mononuclear cells in the spleen, NALT, CLNs, and MeLNs were isolated aseptically by a mechanical dissociation method using gentle teasing through stainless steel screens as described previously (14).…”