Costimulatory molecules in the developing human gastrointestinal tract: a pathway for fetal allergen priming

BACKGROUND: Antigen-specific responses can be detected in umbilical cord blood mononuclear cells. The fetal immune system must therefore attain a level of maturity compatible with the initiation of such responses as well as be exposed to antigen. OBJECTIVE: We sought to assess the expression of costimulatory molecules in fetal gut and the presence of cytokines in amniotic fluid at this time as a preliminary analysis of the suitability of the fetal gut as a site of antigen priming during intrauterine life. METHODS: Human fetal gut was analyzed for cells expressing costimulatory molecules through use of immunohistochemistry. Amniotic fluid was studied by ELISA, for cytokines regulating the nature of the response, and as a source of the common dietary antigen ovalbumin. RESULTS: MHC class II--positive cells were abundant over the period examined (11-24 weeks of gestation), other surface antigens showing spatial and temporal variation in expression. From 11 to 14 weeks of gestation, CD68-positive and CD40-positive cells, like MHC class II--positive cells, were present throughout the lamina propria; few CD3-positive cells (T cells) were observed. With the emergence of lymphoid aggregates (14-16 weeks), CD83-positive cells (dendritic cells) and CD20-positive cells (B cells) could be detected in fetal gut; however, expression was restricted to the lymphoid aggregates. In contrast, MHC class II, CD40, and CD68 continued to be expressed in the lamina propria. CD28-positive cells were also evident from 14 weeks of gestation, occurring throughout the lamina propria and lymphoid aggregates; this corresponded to the increasing numbers of CD3-positive cells. The occasional CD86-positive, CD40L-positive, or CTLA4-positive cell could be seen in or around lymphoid aggregates after 14 weeks of gestation. Lymphoid follicles forming after 16 weeks of gestation contained MHC class II--positive, CD83-positive, CD20-positive, CD40-positive, CD86-positive, CD3-positive, CD28-positive, CD40L-positive, and CTLA4-positive cells. MHC class II--positive, CD40-positive, CD68-positive, CD3-positive, and CD28-positive cells continued to be present in the lamina propria at this time. At all times studied, CD14 was not expressed in the lamina propria or lymphoid follicles. Prostaglandin E(2), TGF beta(1), and IL-10 dominated the amniotic fluid cytokine milieu, and ovalbumin was also detectable in amniotic fluid from 3 of 26 women who had detectable circulating levels. CONCLUSION: Of the costimulatory molecules studied, CD40 was the most abundant. However, both of the ligand families studied (CD40-CD40L and CD86-CD28/CD152) could provide the costimulatory signals required for the initiation of antigenspecific reactivity in the gastrointestinal tract of the human fetus as early as 16 weeks of gestation. The cytokine milieu would favor the development of T(H)2-type reactivity to antigens, such as ovalbumin, that are present at this time.     

Disseminated skeletal lesions associated with pathogenic actinomycetes in a Pygmy hog (Sus salvanius)

The clinical and pathological features of an unusual crippling bone disease in an adult male Pygmy Hog, Sus salvanius, born the smallest in a litter of five and representing the rarest of the known living Suidae, are described. Radiological studies revealed severe spondylosis deformans and focal sharply demarcated radiolucencies in virtually the whole skeleton, but particularly in the bones of the skull, the processes of multiple vertebrae, the ribs, scapulae and parts of the humeri and femora. The clinical chemistry measurements were indicative of pathological lytic processes in the skeleton. The focal bone lesions consisted of caseous necrosis, dystrophic calcification and peripheral fibroblastic demarcation. They contained colonies of filamentous bacteria identified as members of the Order Actinomycetales. Case history evidence suggests that the infection may have resulted from repeated skin trauma inflicted by litter-mates.     

Expression of CEA, CA125, CA19-9 and human milk fat globule membrane antigen in ovarian tumours.

The expression of five different antigens in ovarian tumours was studied by means of an immunohistochemical test with anti-CEA, HMFG1 and HMFG2, NS19-9 and OC125 antibodies. Considerable variation was noted not only between different histological types and between tumours of one type but also between areas in a single tumour. HMFG1 and HMFG2 were the most reactive of all the antibodies; NS19-9 and OC125 were expressed by different populations of cells. It is concluded that specific combinations of antibodies are more effective both for the monitoring of ovarian cancer as well as for immunodiagnosis and treatment, than any single one used.     

Effects of nimodipine,Bay K 8644 and pinacidil on α1- and α2-adrenoceptor-mediated vasoconstriction in human hand veins

The effects of nimodipine, Bay K 8644 and pinacidil, three drugs interfering with transmembrane Ca²⁺ fluxes in different ways, were investigated in isolated human hand veins. Their ability to influence the concentration-response relationship for noradrenaline (NA) was assessed in the absence and presence of prazosin or rauwolscine. The contractile response to NA was almost abolished in Ca²⁺-free medium. Nimodipine and pinacidil depressed the NA concentration-response curve both in the absence and presence of α-adrenoceptor blockers. The NA response was only partially inhibited by nimodipine, indicating that NA may activate nimodipine-insensitive influx pathways, presumably receptor-operated calcium channels. Pinacidil inhibited the contractile response to 124 mM K⁺ and reduced the NA-induced contraction in the presence of nimodipine, suggesting that pinacidil has actions other than the opening of potassium channels and subsequent membrane hyperpolarization. Bay K 8644 increased the NA potency fourfold in the presence of rauwolscine, whereas it had no effect on the NA response in the presence of prazosin and in the absence of α-adrenoceptor blockade. Such an action of Bay K 8644 can be reconciled with α-adrenoceptor activation causing membrane depolarization and opening of potential-operated calcium channels. It may be concluded that both α₁- and α₂-adrenoceptor-mediated contractions in human hand veins are highly dependent on Ca²⁺ influx, although the mechanisms utilized to bring about this influx partly differ between the two receptor subtypes.     

Muscarine-sensitive voltage-dependent potassium current in cultured murine spinal cord neurons

Muscarine produced membrane depolarization and decreased membrane conductance of mouse spinal cord neurons in dissociated cell culture. When the neurons were voltage clamped, muscarine evoked inward currents which increased with membrane depolarization and decreased with membrane hyperpolarization. However, the muscarine-induced inward currents did not invert at large negative potentials, suggesting that muscarine decreased a voltage-dependent potassium current (m-current) [2]. Using the voltage-jump current-relaxation technique, m-current was demonstrated in spinal cord neurons and shown to be a muscarine-sensitive potassium current.     

High frequency of CD8αα homodimer-bearing T cells in human fetal intestine

Immunohistochemistry on frozen sections was used to identify CD8αα cells and CD8αβ cells in human intestine. As observed previously, CD8αβ cells predominate (>95%) in tonsil and post-natal intestine. However in human fetal intestine (16–24 weeks gestation), almost half the CD8⁺ cells in the lamina propria are CD8αα, and many CD8αα cells can be identified in the epithelium. In contrast, in the T cell zones of the Peyer's patches, CD8αβ cells are dominant. The CD8αα cells are virtually all αβ T cell receptor positive. By analogy with the murine system, these CD8αα cells in the fetal gut may be directly derived from the marrow, undergoing thymus-independent differentiation in the gut mucosa.     

Undifferentiated columnar cells on the gastric interfoveolar crest: a previously undescribed observation

We have observed and defined morphometrically and histochemically an entity composed of groups of undifferentiated columnar cells on the interfoveolar crest of gastric mucosa. These cells are clearly distinct from either normal foveolar cells or regenerative epithelial cells associated with ulcer healing. They show a close association with atrophic gastritis, particularly in the presence of type 3 sulphomucin-secreting intestinal metaplasia. We have termed this the gastric tip lesion since it is observed only on the tips of the mucosal folds. This has not been described previously. We propose that these cells are the precursors of type 3 intestinal metaplasia and may also provide a link between this type of intestinal metaplasia and the intestinal variant of gastric adenocarcinoma.     

A cardiac myosin binding protein C mutation in the Maine Coon cat with familial hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is one of the most common causes of sudden cardiac death in young adults and is a familial disease in at least 60% of cases. Causative mutations have been identified in several sarcomeric genes, including the myosin binding protein C (MYBPC3) gene. Although numerous causative mutations have been identified, the pathogenetic process is still poorly understood. A large animal model of familial HCM in the cat has been identified and may be used for additional study. As the first spontaneous large animal model of this familial disease, feline familial HCM provides a valuable model for investigators to evaluate pathophysiologic processes and therapeutic (pharmacologic or genetic) manipulations. The MYBPC3 gene was chosen as a candidate gene in this model after identifying a reduction in the protein in myocardium from affected cats in comparison to control cats (P<0.001). DNA sequencing was performed and sequence alterations were evaluated for evidence that they changed the amino acid produced, that the amino acid was conserved and that the protein structure was altered. We identified a single base pair change (G to C) in the feline MYBPC3 gene in affected cats that computationally alters the protein conformation of this gene and results in sarcomeric disorganization. We have identified a causative mutation in the feline MYBPC3 gene that results in the development of familial HCM. This is the first report of a spontaneous mutation causing HCM in a non-human species. It should provide a valuable model for evaluating pathophysiologic processes and therapeutic manipulations.     

Autoradiography of L-type and N-type calcium channels in aged rat hippocampus, entorhinal cortex, and neocortex

The present study examined brains from 6, 17, and 32 month old male (F344x BN)F1 rats to determine whether there was any age-related change in the distribution or density of L-type and N-type Ca2+ channels in hippocampus, entorhinal cortex, and neocortex, areas commonly involved in the generation of epileptic seizures. The L-type channel antagonist PN200-110 and the N-type channel antagonist omega-conotoxin GVIA were used to determine specific binding densities and the autoradiographic distribution of ligand binding was quantified by computer-assisted densitometry. One-way ANOVA noted a significant variance in the mean value of binding density between different age groups only in neocortex laminae IV-VI for [(3)H]PN200-110 binding (P < 0.05). Post-hoc testing indicated that the mean value of the 17 month old group was significantly less than those of the 6 and 32 month old groups (P < 0.05). These results indicate no overall age-related change in the number of L-type and N-type Ca2+ channels in brain areas frequently involved in seizure activity and suggest that age-related changes in brain Ca2+ physiology may be associated with changes in voltage-gated Ca2+ channel function rather than channel number.