The selective induction of antibodies in external secretions is desirable for the prevention of various systemic as well as predominantly mucosa-restricted infections. An enormous surface area of mucosal membranes is protected primarily by antibodies that belong, in many species, to the IgA isotype. Such antibodies are produced locally by large numbers of IgA-containing plasma cells distributed in subepithelial spaces of mucosal membranes and in the stroma of secretory glands. In humans and in some animal species, plasma-derived IgA antibodies do not enter external secretions in significant quantities and systemically administered preformed IgA antibodies would be of little use for passive immunization. Systemic administration of microbial antigens may boost an effective S-IgA immune response only in a situation whereby an immunized individual had previously encountered the same antigen by the mucosal route. Local injection of antigen in the vicinity of secretory glands is usually accompanied by an undesirable concomitant systemic response and frequently requires the addition of adjuvants that are unacceptable for administration in humans. Immunization routes that involve ingestion or possibly inhalation of antigens lead to the induction of not only local but also generalized immune responses manifested by the parallel appearance of S-Iga antibodies to ingested or inhaled antigens in secretions of glands distant from the site of immunization. Based on extensive studies in animal models as well as in humans, convincing evidence is available that antigen-sensitized and IgA-committed precursors of plasma cells from GALT are disseminated to the gut, other mucosa-associated tissues, and exocrine glands. However, due to the limited absorption of desired antigens from the gut lumen of orally immunized individuals, repeated large doses of antigens are required for an effective S-IgA response. Novel antigen delivery systems for the stimulation of such responses are currently being examined in several laboratories. Live attenuated or genetically manipulated bacteria expressing other microbial antigens have also been used for selective colonization of gut-associated lymphoid tissues. Unique antigen packaging and the use of adjuvants suitable for oral administration hold promise for an efficient antigen delivery to critical tissues in the intestine and deserve extensive exploration. The oral immunization route appears to have many advantages over systemic immunization.(ABSTRACT TRUNCATED AT 400 WORDS)

The common mucosal immune system and current strategies for induction of immune responses in external secretions

Butyrylcholinesterase is a serine hydrolase related to acetylcholinesterase that catalyses the hydrolysis of esters of choline, including acetylcholine. Butyrylcholinesterase has unique enzymatic properties and is widely distributed in the nervous system, pointing to its possible involvement in neural function. Here, we summarize the biochemical properties of butyrylcholinesterase and review the evidence that this enzyme has important roles in cholinergic neurotransmission and could be involved in other nervous system functions and in neurodegenerative diseases.

Neurobiology of butyrylcholinesterase.

Enterotoxigenic Escherichia coli (ETEC) of several different serotypes isolated from adults with diarrhea and known to possess the colonization factor antigen (CFA) were found to cause mannose-resistant hemagglutination (HA) of human group A erythrocytes. CFA-negative E. coli isolated during the same study did not possess the mannose-resistant hemagglutinin, although some non-ETEC, CFA-negative isolates did exhibit mannose-sensitive HA activity. The mannoseresistant hemagglutinin of ETEC was found to possess many characteristics previously associated with CFA, which is a surface-associated fimbriate heatlabile antigen, and the functionally and morphologically similar K88 and K99 antigens of animal-specific ETEC. Mannose-resistant HA and CFA titers were maximal when ETEC cells were grown on an agar medium (CFA agar) composed primarily of 1% Casamino Acids and 0.15% yeast extract, pH 7.4. Neither CFA nor HA were produced at a growth temperature of 18°C; HA was completely inhibited by pretreatment of CFA-positive cells with the anti-CFA serum. The mannose-resistant hemagglutinin was lost spontaneously and simultaneously with CFA when clinical ETEC isolates were passaged on artificial medium in the laboratory, indicating plasmid control of both entities. The mannose-resistant hemagglutinin of ETEC was shown to be thermolabile, i.e., sensitive to heating at 65°C, as was the CFA. Also, there was correlation between possession of CFA, as detected serologically and by demonstration of biological activity (adherence in the infant rabbit small intestine), presence of CFA-type fimbriae, and the ability of various E. coli isolates to cause mannose-resistant HA of human group A erythrocytes. These results indicate that the mannose-resistant HA of ETEC is another manifestation of CFA.

https://iai.asm.org/content/iai/18/2/330.full.pdf

Hemagglutination of Human Group A Erythrocytes by Enterotoxigenic Escherichia coli Isolated from Adults with Diarrhea: Correlation with Colonization Factor

Zimbabwe offers the most recent example of the tragedy that befalls a country and its people when cholera strikes The 2008–2009 outbreak rapidly spread across every province and brought rates of mortality similar to those witnessed as a consequence of cholera infections a hundred years ago In this Review we highlight the advances that will help to unravel how interactions between the host, the bacterial pathogen and the lytic bacteriophage might propel and quench cholera outbreaks in endemic settings and in emergent epidemic regions such as Zimbabwe

/pdf/cholera-transmission-the-host-pathogen-and-bacteriophage-3xua70r6v5.pdf

Cholera transmission: the host, pathogen and bacteriophage dynamic

Letter: Passive immunity against childhood cancer.

Virus particles in epithelial cells of duodenal mucosa from children with acute non-bacterial gastroenteritis.

Detection of a new virus by electron microscopy of fæcal extracts from children with acute gastroenteritis

Rotavirus infections in obstetric hospitals

Is lactase the receptor and uncoating enzyme for infantile enteritis (rota) viruses

Noncultivable viruses have been associated with diarrhea affecting newborn babies in obstetric hospital nurseries. Persisting infection in a special care nursery in Melbourne, Australia, permitted a study of the pattern of excretion of these viruses. Ten babies admitted to the nursery within 2 hr of birth were randomly selected for prospective study. Feces were collected daily for 14 days and were examined by electron microscopy. All ten babies excreted detectable amounts of duovirus (rotavirus, HRVL agent, IGV) for at least 1 day. Age at onset of excretion varied from 2 to 13 days. Eight of the ten babies developed diarrhea. Excretion of duovirus preceded the onset of diarrhea by 12–72 hr and persisted for at least 3 days.



Seven of the ten babies also excreted detectable amounts of a 28-nm virus-like particle for 3–8 days. The identity of this particle is unknown. Morphologically it resembles Norwalk agent and “astrovirus.” Excretion of this 28-nm particle coincided with symptoms of diarrhea in four babies, all of whom were also excreting duovirus.



It is concluded that most newborn babies admitted to a nursery where duovirus infection is endemic will excrete this virus at least once during the first 2 weeks of life. Excretion of virus particles will either precede development of diarrhea or be asymptomatic. Selective isolation of babies with diarrhea is thus unlikely to control spread of duovirus infection within a hospital nursery.

B.J. Ruck

Papers

Virus particles in epithelial cells of duodenal mucosa from children with acute non-bacterial gastroenteritis.

Detection of a new virus by electron microscopy of fæcal extracts from children with acute gastroenteritis

Rotavirus infections in obstetric hospitals

Is lactase the receptor and uncoating enzyme for infantile enteritis (rota) viruses

Pattern of shedding of two noncultivable viruses in stools of newborn babies.