Differential Uptake and Processing of a Haemophilus influenzae P5-Derived Immunogen by Chinchilla Dendritic Cells

Abstract

Dendritic cells (DCs) are potent antigen-presenting cells involved in the initiation and modulation of immune responses after immunization via their ability to process and present antigen to naive T cells. We wanted to examine the role of DCs in the development of protective immunity against nontypeable Haemophilus influenzae (NTHI)-induced experimental otitis media (OM) after intranasal immunization of chinchillas with an NTHI P5-derived synthetic peptide immunogen called LB1. As chinchilla DCs have not been described, we adapted well-established protocols to induce the differentiation of chinchilla bone marrow precursor cells into DCs, which resulted in cells that were morphologically and phenotypically similar to DCs of other species. In vitro, chinchilla DCs readily internalized LB1, upregulated expression of the maturation markers CD80 and major histocompatibility complex class II, and presented processed LB1 to primed CD3 ؉ T cells, which resulted in antigen-specific T-cell proliferation. In vivo, LB1-activated DCs trafficked from the chinchilla nasal cavity primarily to the nasal-associated lymphoid tissues and were detected in close proximity to CD3 ؉ T cells within this lymphoid aggregate. These data are the first to characterize chinchilla DCs and their functional properties. Furthermore, they suggest an important role for chinchilla DCs in the development of protective immunity against experimental NTHI-induced OM after intranasal immunization.

Construction and Immunogenicity of Recombinant Adenovirus Vaccines Expressing the HMW1, HMW2, or Hia Adhesion Protein of Nontypeable Haemophilus influenzae

“…We demonstrated the immunogenicity of these constructs when delivered by the parenteral and the intranasal route in the chinchilla model. As noted earlier, the chinchilla model is the system favored by most research groups in the field for the study of otitis media pathogenesis (2) and for assessment of the protective potential of otitis media vaccine candidates (5,48). Future studies of our adenoviral constructs will be needed to define the optimal immunization regimen for generation of a protective immune response in the chinchilla model.…”

“…Future studies of our adenoviral constructs will be needed to define the optimal immunization regimen for generation of a protective immune response in the chinchilla model. Important issues yet to be addressed include the ability of the immunization regimens that we develop to induce a functional antibody response (64,65), the ability of the constructs to induce a mucosal immune response in the upper airway (48), and the potential benefit of prime-boost immunization regimens to enhance the protective immune response in the vaccinees (21).…”

“…Components of both the innate and adaptive immune systems are thought to mediate protection of the middle ear space against infection (36,38,59). The nasal mucosa-associated lymphoid tissue (NALT) has been proposed as a primary inductive site for upper respiratory tract mucosal immune responses (36,56), and recent studies have begun to investigate the trafficking of lymphocytes to the middle ear mucosa (35,48,59). In response to antigenic stimulation, dendritic cells in the chinchilla nasal mucosa have been shown to traffic to the NALT, where they presumably initiate an antigenspecific immune response (48).…”

“…The nasal mucosa-associated lymphoid tissue (NALT) has been proposed as a primary inductive site for upper respiratory tract mucosal immune responses (36,56), and recent studies have begun to investigate the trafficking of lymphocytes to the middle ear mucosa (35,48,59). In response to antigenic stimulation, dendritic cells in the chinchilla nasal mucosa have been shown to traffic to the NALT, where they presumably initiate an antigenspecific immune response (48). Recombinant adenoviral vectors have been shown to be potent activators of dendritic cell maturation in several experimental systems (42,52).…”

Bench and bedside advances in otitis media

“…However, one interesting development is the utilization of protein D, which has demonstrated efficacy in limiting both pneumococcal and NTHi OM in both animals and a recent human trial 24 (**). It is clear that significant progress continues to be made in many other areas as well 25 (*), 26 (*) and that development of an effective NTHi vaccine will reach fruition, which in turn, will have a major impact on the management of OM.…”