(28). The transfer membranes were blocked with 20% (wt/vol) nonfat milk in 0.05% (vol/vol) PBST overnight at 5C. concentrations were significantly greater in miniature schnauzers than in GSD (P< 0.0001), Labradors (P< 0.0001), and beagles (P= 0.0098). These findings do not support the hypothesis that GSD have a relative deficiency in fecal IgA. The differences in immunoglobulin concentrations measured from a single defecation, between individuals of the same breed and between breeds, as well as the lack of an internal control molecule, make the determination of a normal reference range for all dogs impossible. Therefore, the usefulness of fecal immunoglobulin quantification for the assessment of intestinal immunoglobulin secretion in dogs is limited. Selective immunoglobulin A (IgA) deficiency is the most common primary immunodeficiency in humans (7) and has been associated with chronic gastrointestinal Clemizole hydrochloride disease (7,25). This observation is one factor that has led to the suggestion that the susceptibility of German shepherd dogs (GSD) to chronic enteropathies is related to defective production of IgA by the intestinal mucosa. Relatively low serum IgA concentrations occur in GSD either with or without alimentary disease (2,16,30,31), yet the concentration of IgA in serum correlates poorly with that in mucosal secretions. Therefore, a number of studies have measured the concentration of IgA in the tears (8), saliva (13), duodenal juice (2), 24-h duodenal explant culture supernatants (13), and feces (21) of GSD to determine whether they have a relative deficiency in mucosal IgA production. Indeed, lower concentrations of IgA have been found in the tears (8), duodenal juice (2), and 24-h duodenal mucosa explant culture supernatants (13) of GSD than in those of other breeds of dogs. These findings contrast with the observation that within the same populations, there are equivalent numbers of IgA+plasma cells within the lamina propria of the duodenal mucosa (2,13). Humans with IgA deficiency have been found to have undetectable levels of IgA in their feces (17). One study of canine fecal immunoglobulins found lower concentrations of IgA in the feces of GSD than in those of a control group of Labrador-retrievers (21). For each individual, the fecal IgA concentration was found to be significantly correlated with the IgA concentration in supernatants taken from duodenal explant cultures. The aim Clemizole hydrochloride of the present study was to confirm whether a relative deficiency of IgA exists in the feces of GSD. Fecal samples were collected from a large number of GSD, Labrador-retrievers, beagles, and miniature schnauzers in order to allow comparison of IgA concentrations between multiple breed groups. == MATERIALS AND METHODS == == Samples. == A single fecal sample was obtained from the first spontaneous defecation of the day from each dog and was stored in a preweighed fecal collection tube (Sarstedt, Numbrecht, Germany). Samples were then stored at 70C for as long as 3 months in order to allow batching of the samples for extraction. Fecal samples were collected from two groups of dogs (Table1). Group 1 consisted of 209 privately owned GSD that were kept either as household pets or in kennelled groups. The median kennel group size was 5 (range, 1 to 24). All dogs were healthy at the time of collection and had no history of diarrhea. == TABLE Clemizole hydrochloride 1. == Sample groupsa The dogs from which the fecal samples were collected are divided into individual breed groups. The GSD group contained a large proportion of nonneutered animals of both sexes and a larger proportion of females than the other three breed groups. The groups were not age matched; GSD were significantly younger (P< 0.0001) and beagles were significantly older (P< 0.001) than dogs in the other three groups. There was no significant difference in age between Labradors and miniature schnauzers (P= 0.325). Group 2 consisted of 147 dogs kept in a single large colony. Breeds represented included Labradors (n= 96), miniature schnauzers (n= 32), and beagles (n= 19). The dogs were housed in small groups and were regularly walked outside the housing facility. == Fecal immunoglobulin Mouse monoclonal to RTN3 extraction. == The method used for saline extraction of fecal immunoglobulin was adapted from that used by Ferguson et al. (11). Approximately 1 g (wet weight) of feces was contained in the sample scoop of the fecal tube. The wet weight of feces extracted ranged from 0.83 to 2.16 g (median, 1.24 g). Extraction buffer (0.01 M phosphate-buffered saline [PBS] [pH 7.4], 0.5% Tween [Sigma-Aldrich, Poole, Dorset, United Kingdom], and 0.05% sodium azide) was added to each tube at a ratio of 10 ml.