Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have developed an animal model for congenital syphilis. Treponema pallidum is injected intravenously into pregnant rabbits and fetuses are infected in utero. As a prelude to characterizing the immunologic consequences of fetal infection, it was necessary to expand on the baseline information about newborn rabbit immune capabilities. Studies were undertaken to determine splenic macrophage and T lymphocyte functions with emphasis on newer immunologic parameters. Newborns aged 2 weeks were compared to adults. Macrophage capabilities in newborn rabbits differed from those of their adult counterparts. These cells produced similar basal levels of interleukin 1 (IL-1) but failed to respond to the IL-1 stimulants of lipopolysaccharide (LPS) or T. pallidum. Macrophages also exhibited diminished levels of la expression and increased levels of prostaglandin E2 (PGE2) secretion. T lymphocyte functions were altered in newborn spleen preparations. Following concanavalin A (Con A) stimulation, interferon gamma production was half that of adults; in direct contrast, IL-2 production was twice that of adults. Con A-induced lymphocyte proliferation was markedly decreased in newborn preparations. This diminished response resulted from down-regulation rather than immaturity. When newborn splenic cells were stimulated with Con A in the presence of indomethacin, anti-transforming growth factor (anti-TGF), or exogenous IL-1/IL-2, better proliferation resulted. PGE2, which is well established as a down-regulator of newborn immune functions in human and mouse systems, also appears to play a role in suppressing newborn rabbit functions. TGF is a potent suppressor of a number of adult immunologic reactions. This is the first documentation of the potential role of this factor in down-regulating newborn immune capabilities. These findings provide a framework for future investigations of our congenital syphilis model.
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PMID:Macrophage and lymphocyte functions are down-regulated in newborn rabbits. 143 51

Previous studies have shown that recombinant interferon gamma (IFN-gamma), crude T cell supernatants, or appropriate T-cell lines can cause total inhibition of the growth of M. tuberculosis inside murine peritoneal macrophages. In similar experiments with human monocytes much smaller effects are seen. This could be due to the relative immaturity of these cells. Because dihydroxy vitamin D3 (1,25-(OH)2 D3) can cause phenotypic differentiation of immature leukemic lines into macrophage-like cells, we have explored the possibility that exposure to cholecalciferol metabolites in vitro might increase the ability of monocytes to control proliferation of M. tuberculosis, or cause monocytes to mature into cells able to respond appropriately to IFN-gamma. Incubation of monocytes with three cholecalciferol metabolites induced anti-tuberculosis activity to an extent that correlated with their binding affinities to the intracellular receptor protein for the derivatives. 1,25-(OH)2 D3 also primed monocytes for phorbol myristate acetate-triggered reduction of nitroblue tetrazolium. The effects were additive rather than synergistic with those of IFN-gamma. Monocytes incubated with IFN-gamma developed 25-OH D3 1-hydroxylase activity, detected by conversion of tritiated 25-(OH) D3 to a more polar metabolite which coeluted with 1,25-(OH)2 D3 on straight and reverse-phase HPLC. The latter is a more active form in vivo. These findings help to explain claims for the efficacy of vitamin D in the treatment of some forms of tuberculosis, and also the occasional finding of raised serum calcium, and disturbed vitamin D metabolism in these patients.
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PMID:Vitamin D3, gamma interferon, and control of proliferation of Mycobacterium tuberculosis by human monocytes. 300 68

The relative inefficiency of respiratory mucosal immune function during infancy is generally attributed to the immaturity of the neonatal T cell system. However, immune competence in the adult lung has recently been shown to be closely linked to the functional capacity of local networks of intraepithelial dendritic cells (DC). This study examines the density and distribution of these DC throughout the neonatal respiratory tract in rats, focusing particularly on microenvironmental regulation of their class II major histocompatibility complex (MHC) (Ia) expression. In animals housed under dust-controlled conditions, airway epithelial and alveolar Ia+ DC detectable by immunostaining with the monoclonal antibody (mAb) Ox6 are usually not seen until day 2-3 after birth, and adult-equivalent staining patterns are not observed until after weaning. In contrast, the mAb Ox62 detects large numbers of DC in fetal, infant, and adult rat airway epithelium. Costaining of these Ox62+ DC with Ox6 is rare in the neonate and increases progressively throughout infancy, and by weaning Ia+ DC comprised, on average, 65% of the overall intraepithelial DC population. In infant rats, Ia+ DC are observed first at the base of the nasal turbinates, sites of maximum exposure to inhaled particulates, suggesting that their maturation is driven in part by inflammatory stimuli. Consistent with this suggestion, densitometric analysis of Ia staining intensity of individual DC demonstrates that by 2-3 d after birth, Ia expression by nasal epithelial DC was comparable with that of Iahigh epidermal Langerhans cells in adjacent facial skin, at a time when expression by tracheal epithelial DC was 7-10-fold lower. Additionally, the rate of postnatal appearance of Iahigh DC in the airway epithelium was increased by administration of interferon gamma, and decreased by exposure of infant rats to aerosolized steroid. These findings collectively suggest that Ia expression by neonatal respiratory tract DC is locally controlled and can be upregulated by mediators that are produced within the lung and airway epithelium in response to inhalation of proinflammatory stimuli. It was also noted that Ialow neonatal airway DC expressed adult equivalent levels of class I MHC, which suggests differences in capacity to prime for CD8(+)-dependent versus CD4(+)-dependent immunity to inhaled pathogens, during the early postnatal period.
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PMID:Development of the airway intraepithelial dendritic cell network in the rat from class II major histocompatibility (Ia)-negative precursors: differential regulation of Ia expression at different levels of the respiratory tract. 827 Aug 65