Mucin is produced by clara cells in the proximal airways of antigen-challenged mice

Airway mucus hypersecretion is a prominent feature of many obstructive lung diseases. We thus determined the ontogeny and exocytic phenotype of mouse airway mucous cells. In naive mice, ciliated (approximately 40%) and nonciliated (approximately 60%) epithelial cells line the airways, and > 95% of the nonciliated cells are Clara cells that contain Clara cell secretory protein (CCSP). Mucous cells comprise < 5% of the nonciliated cells. After sensitization and a single aerosol antigen challenge, alcian blue-periodic acid Schiff's positive mucous cell numbers increase dramatically, appearing 6 h after challenge (21% of nonciliated/nonbasal cells), peaking from Days 1-7 (99%), and persisting at Day 28 (65%). Throughout the induction and resolution of mucous metaplasia, ciliated and Clara cell numbers identified immunohistochemically change only slightly. Intracellular mucin content peaks at Day 7, and mucin expression is limited specifically to a Clara cell subset in airway generations 2-4 that continue to express CCSP. Functionally, Clara cells are secretory cells that express the regulated exocytic marker Rab3D and, in antigen-challenged mice, rapidly secrete mucin in response to inhaled ATP in a dose-dependent manner. Thus, Clara cells show great plasticity in structure and secretory products, yet have molecular and functional continuity in their identity as specialized apical secretory cells.     

Production and characterization of monoclonal antibodies to ARVCF

We have generated the first monoclonal antibodies (MAbs) to Armadillo repeat gene deleted in velo-cardiofacial syndrome (ARVCF), a recently identified Armadillo repeat-containing protein closely related to the catenin p120ctn. Six ARVCF-specific MAbs were characterized for isotype, species cross-reactivity, and utility in assays including immunofluorescence, immunoprecipitation, and Western blotting. All six antibodies were isotyped as IgG1 and several cross-reacted with ARVCF from a variety of species including human, rat, dog, and monkey, but not mouse. Importantly, none of the ARVCF MAbs cross-reacted with p120ctn, despite the high homology between these proteins. MAbs 3B2 and 4B1 were consistently the best in all applications and will provide valuable tools for further study of the role of ARVCF in cells.     

The effects of storage of blood and isolated DNA on the integrity of DNA

Long-term storage of DNA is required for a number of genetic studies; prior to extraction, blood samples may be subject to elevated temperatures for variable intervals. We have studied the effect of temperatures ranging from ?70°C to +65°C on human blood and on DNA extracted from it. DNA in solution stored at ambient temperatures up to 37°C for 6 months was digestible by three different restriction endonucleases, whereas storage at 45°C is deleterious after 6-7 weeks. DNA can be extracted from blood samples stored at ?70°C for at least 2 months or at 23°C for a week or more, but blood stored at these temperatures may yield less high-molecular-weight DNA. Cell pellets from which plasma has been removed also can serve as a source of DNA. Isolated DNA stored dry for years (up to 30) is difficult to dissolve and may appear degraded, but a sample stored dry for 13 years and then in solution at ?20°C for 7 years appeared to be intact.     

Natural killer cell activity in the rat. VI. Characterization of rat large granular lymphocytes as effector cells in natural killer and antibody-dependent cellular cytotoxic activities

The present study examined rat natural killer (NK) cells, which mediate not only NK activity but also antibody-dependent cellular cytotoxicity (ADCC). NK and ADCC activities were compared with regard to organ distribution, strain distribution, Percoll fractionation of the effector cells, effects of aging, and potential to be augmented by biological response modifiers (BRM). Like NK activity, appreciable ADCC activity was observed in peripheral blood leukocytes (PBL), splenic leukocytes (SPL), and peritoneal exudate cells (PEC), but not in cell preparations from the peripheral lymph nodes (PLN), mesenteric lymph nodes (MLN), bone marrow (BM), and thymus (THY). ADCC activity, when compared with NK activity, was significantly higher in PBL but the same or lower in SPL and PEC. In terms of strain distribution, a high NK/ADCC strain (rnu/rnu), four intermediate NK and high ADCC strains (PVG/RTLRL, Lewis, PVG/OLA, and F344), an intermediate NK/ADCC strain (WF/N), and a low NK/ADCC strain (Buffalo) were observed. Fractionation of effector cells on discontinuous Percoll gradients revealed that both NK and ADCC activities were associated with relatively high-density large granular lymphocytes (LGL). In contrast, ADCC but little or no NK activity was associated with lower density LGL. However, the NK activity of this lower-density LGL population could be elicited following the in vitro incubation with a number of BRM, including rat interferon (IFN) and OK-432, but not rat interleukin-2 (IL-2). In general, the ADCC activity of both higher and lower density LGL-enriched cell populations correlated with both the frequency of FC gamma R+ LGL and the percentage of LGL binders to antibody-coated P815 target cells. The present study also has shown that in contrast to NK activity, which remained relatively stable with age, ADCC activity from F344 but not WF/N rats increased until 30-50 wk of age. This increase of ADCC activity in older F344 rats was accompanied by an increase in the percentage and absolute number of lower density FC gamma R+ LGL. This study demonstrates a number of similarities and differences between NK and ADCC activities in the rat. These findings should be useful for further examining and comparing the in vivo development and biological role of these two effector arms of the immune system.     

A mouse model of galactose-induced cataracts

Galactokinase (GK; EC 2.7.1.6) is the first enzyme in the metabolism of galactose. In humans, GK deficiency results in congenital cataracts due to an accumulation of galactitol within the lens. In an attempt to make a galactosemic animal model, we cloned the mouse GK gene (Glk1) and disrupted it by gene targeting. As expected, galactose was very poorly metabolized in GK-deficient mice. In addition, both galactose and galactitol accumulated in tissues of GK-deficient mice. Surprisingly, the GK-deficient animals did not form cataracts even when fed a high galactose diet. However, the introduction of a human aldose reductase transgene into a GK-deficient background resulted in cataract formation within the first postnatal day. This mouse represents the first mouse model for congenital galactosemic cataract.     

Congenital cytomegalovirus infection.

The overall prevalence of congenital cytomegalovirus infection among the offspring of a highly immune young female population was 2.4 per cent (23 of 939). To ascertain whether the presence of anticytomegalovirus antibodies protects the developing fetus, we examined the offspring of 239 prospectively studied women. Despite substantial levels of preconceptional antibodies, intrauterine cytomegalovirus infection occured in seven of 208 (3.4 per cent) seroimmune women. Three neonates with congenital infection were born to 31 initially seronegative women. All the congenitally infected infants had subclinical involvement. Maternal humoral immunity may not protect the fetus against congenital cytomegalovirus infection. Neutralization kinetics and restriction enzyme analysis with endonucleases (EcoR-1 and HinD 111) demonstrated antigenic and genetic homology between viral strains isolated from two siblings consecutively infected in utero, indicating that repeat maternal infection with the same virus is transmissible to sequential products of conception.     

Cellular immunity in Peyer''s patches of rats infected with Trichinella spiralis.

A rat model of Trichinella spiralis gut infection was used to observe the sequence of developing cellular immunity in Peyer's patches and other lymphoid tissues. Whereas cellular reactivity (lymphocyte blastogenesis) for worm antigens was evident in mesenteric lymph nodes draining the gastrointestinal tract within 3 days after infection, Peyer's patch lymphocytes developed maximal reactivity 2 to 3 weeks later at the same time as the spleen and other lymphoid tissues. Furthermore, the immune reactivity found in Peyer's patches was only transient. Thus, in this parasitic gut infection, the Peyer's patch lymphoid tissue does not appear to be the first site of cellular responsiveness but rather to acquire cellular reactivity only when other lymphoid elements in the infected host have also acquired similar antigen-induced reactivity.     

Origin and fate of fetuin-containing neurons in the developing neocortex of the fetal sheep

Summary The development of the neocortex has previously been extensively studied in carnivores (cat and ferret), rodents (rat and mouse) and primates (monkey and human). In these species, it has been shown that the initial population of cells migrating from the ventricular zone forms the primordial plexiform layer. This is subsequently split into marginal zone and subplate zone by the insertion of later-migrating cells into the primordial plexiform layer, to form the cortical plate proper. Many of the cells derived from the split primordial plexiform layer are transient. The neurons of the subplate zone are found in the deeper part of layer VI, and white matter deep to layer VI in the more mature cortex; most of these neurons disappear by adulthood. [³H]-thymidine labelling in the present study has shown a similar pattern of neocortical development in Artiodactyla (sheep). In addition it has been shown that the previously described staining of subplate and cortical plate cells for the fetal protein fetuin indicates that fetuin is a useful marker for a proportion of this transient population of neurons and defines its extent in neocortical development more clearly. Dividing cells were labelled by a single intra-amniotic injection of [³H]-thymidine at E26 to E35 (birth is at E150). The brains were subsequently examined at E40 or E80 for [³H]-thymidine labelling and fetuin staining by a combination of autoradiography and immunocytochemistry. The earliest generated neocortical cells detected in this study (E26) were found in two layers by E40, the outer marginal zone and inner subplate zone. Neurons of the marginal zone were generated up to E28; those of the early subplate zone were generated up to E31. The cortical plate proper was generated by cells born on E32 and later. This sequence is similar to that described in other species, especially the cat. A proportion of the early-generated neurons in the marginal zone, subplate zone and early cortical plate stained for fetuin. By E80 these earliest-generated, fetuin-positive cells were found in the white matter deep to the forming neocortical layers and in layer VI. In adult brains no fetuin-positive neurons could be identified in the neocortex, and neurons had almost entirely disappeared from the white matter. The fetal glycoprotein fetuin seems to be specifically associated with a population of cells that has the same developmental history as the transient marginal zone and subplate neurons described in other species. However, the distribution of fetuin-containing neurons is more extensive and includes some of the neurons within the cortical plate itself. Thus in addition to being a marker for a proportion of the transient marginal zone and subplate cells, the presence of fetuin in subplate and cortical plate neurons, given the trophic properties attributed to fetuin, may indicate its involvement in early stages of synaptogenesis and connectivity in the developing neocortex.