Non-Reflex Defense Mechanisms of Upper Airway Mucosa: Possible Clinical Application

Abstract

The sinonasal mucosa has an essential role in defense mechanisms of the upper respiratory tract. The innate immune system presents the primary defense against noxious microorganisms followed by induction of the adaptive immune mechanisms as a consequence of the presence of pathogens. This well-known activation of adaptive immune system in response to presence of the antigen on mucosal surfaces is now broadly applicated in vaccinology research. Prevention of infectious diseases belongs to substantial challenges in maintaining the population health. Non-invasive, easily applicable mucosal vaccination purposes various research opportunities that could be usable in daily practice. However, the existence of multiple limitations such as rapid clearance of vaccine from nasal mucosa by means of mucociliary transport represents a great challenge in development of safe and efficient vaccines. Here we give an updated view on nasal functions with focus on nasal mucosal immunity and its potential application in vaccination in nearly future.

Seltene Erkrankungen der Nase, der Nasennebenhöhlen und der vorderen Schädelbasis

“…Die intakte Funktion der Mukosa beinhaltet einen Schleimfilm, der sich mithilfe der Zilien in konstanter Bewegung befindet. Diese Schicht stellt zum einen die Befeuchtung der eingeatmeten Luft sicher und stellt andererseits, gemeinsam mit dem Niesreflex, eine Barriere gegenüber eingeatmeten Fremdkörpern oder Erregern dar 3 4 . Die gleichmäßige Verteilung der eingeatmeten Luft über eine möglichst große Fläche nasaler Schleimhaut ist für die intakte Funktion der Nase essenziell 4 5 6 7 .…”

“…The intact function of the mucosa consists of a mucosal film that moves continuously by means of cilia. This layer ensures the humidification of the inspired air and on the other hand it is a barrier against inhaled foreign bodies or pathogens together with the sneezing reflex 3 4 . The regular distribution of the inhaled air over a possibly large surface of the nasal mucosa is essential for the intact function of the nose 4 5 6 7 .…”

Pathophysiology of Pediatric Ear, Nose, and Throat Infections

“…Similarly, nasal secretions contain lactoferrin and components of innate immunity. There are significant levels of IgA and IgG present in nasal secretions, originating from the submucosal plasma cells which contribute to adaptive immunity [5,6]. Considering that nasal secretions follow a pathway towards the nasopharynx and oropharynx before swallowing they are an additional antimicrobial film for the pharyngeal mucosa.…”

Lactoferrin and Lysozyme Inhibit the Proteolytic Activity and Cytopathic Effect of Naegleria fowleri Enzymes

“…Amoeba access to the host occurs via the nasal route, and the trophozoites travel through the olfactory neuroepithelium and cross the cribriform plate until they reach the olfactory bulbs, causing intense tissue damage [1]. The nasal mucosa filters approximately seven liters of air per minute and is a barrier against foreign particles and microorganisms [2]. The elimination of potential pathogens is related to the presence of antimicrobial proteins, including mucins, antimicrobial peptides, lysozymes, lactoferrins, and immunoglobulins [3].…”