Mucosal IgA elaboration

Total IgA and IgG in Sera of Patients With Different Primary Malignancies

The concentrations of total serum IgA and IgG of 267 patients with different primary malignant tumors were measured by ELISA. Total serum IgA increased by 30% to 40% in patients with malignancies associated with mucous membranes (nasopharyngeal, gastrointestinal and bronchial carcinomas), while the change in total serum IgG was negligible. Although, the changes in Ig level could be influenced by many host factors, these data call attention to the potential indicative role of total serum IgA levels. Further studies are required to establish links between serum IgA levels and stages of tumor growth or tumor progression in order to use these values as prognostic factors.

Human monocyte-derived macrophages infected with virulent Shigella flexneri in vitro undergo a rapid cytolytic event similar to oncosis but not apoptosis

Infection of human monocyte-derived macrophages in vitro with virulent Shigella flexneri resulted in cell death which involved rupture of the plasma membrane, cell swelling, disintegration of ultrastructure, and generalized karyolysis. These features bore resemblance to oncosis and are in striking contrast to previously described observations of mouse macrophages, where a similar infection by virulent Shigella resulted in cell death by apoptosis. Cell death by oncosis in human macrophages was confirmed by lactate dehydrogenase release, light microscopy, electron microscopy, terminal deoxynucleotidyltransferase end labeling of DNA ends, DNA fragmentation assays, and fluorescence-activated cell sorter analysis of propidium-labeled nuclei. Thus, the phenomena of cell death induced by virulent Shigella in human and mouse macrophages reflect different biochemical pathways. Interleukin-1beta (IL-1beta) was released in culture supernatants of human macrophages infected with virulent bacteria. Inhibition with IL-1beta-converting enzyme inhibitors indicated, however, that this release occurred as a passive event of cell lysis. The patterns of intracellular survival of Shigella strains within human and mouse macrophages reflect differences that exist not only between Shigella serotypes but also between the two different macrophage cell types.

Immunoglobulin concentrations in nasal lavage fluids in dogs with non-specific rhinitis

The pathophysiology of non-specific chronic rhinitis(NSCR) in dogs is still unknown. In this study the possible role of immunological mechanisms in NSCR is examined, by comparing immunoglobulin concentrations in nasal lavage fluids of dogs with NSCR with those of healthy dogs. The immunoglobulin IgA was detected in nasal lavage fluids of both groups of dogs and the differences in relative levels of IgA in dogs with NSCR were not significant. IgM, IgG(a,b), and IgG(d) were detected more frequently in dogs with NSCR (P<0.05), and the relative levels were higher. The presence of IgG(a,b) may indicate the chronic character of rhinitis, and the presence of IgG(d) the possibility of an allergic component in its pathophysiology. The role of IgM is not completely clear.

The protective role of enteral IgA supplementation in neonatal gut origin sepsis

Preterm infants and infants unable to breast feed are particularly susceptible to gut origin sepsis. Many studies have shown the benefits of breast milk in decreasing the incidence of bacterial infections in neonates. Little in vivo work has focused on prevention of neonatal gut origin sepsis with breast milk components. The aim of this study was to determine whether supplementation of a standard neonatal formula with exogenous, luminally administered, human secretory IgA protects against gut origin sepsis in a newborn rabbit model. Sixty New Zealand white rabbit pups were delivered by cesarean section 1 day preterm and divided into two groups--the IgA group (n = 26) and the non-IgA group (n = 34). Animals were gavage-fed a standard artificial formula (KMR) twice daily. The IgA group was supplemented on days 3 and 4 with 6.25 mg/kg of human secretory IgA. The non-IgA group received an equal volume of saline. On the evening of day 3, the animals were orally challenged with Escherichia coli K100. The quantity of bacteria that colonized the cecum was similar in the two groups. The quantity of bacteria that translocated to the mesenteric lymph node, liver, and spleen was significantly lower in the IgA group (P < .05). The incidence of translocation to the organs was also significantly lower in the IgA group (P < .05). The exogenous secretory IgA showed specificity to E coli K100 by ELISA. These data show that neonatal formula supplemented with human secretory IgA decreases the incidence and quantity of bacterial translocation of E coli K100 in a neonatal rabbit model.(ABSTRACT TRUNCATED AT 250 WORDS)