Nonspecific lymphocyte responses in F344 and LEW rats: susceptibility to murine respiratory mycoplasmosis and examination of cellular basis for strain differences.

Mycoplasma pulmonis produces a mitogen which may play a role in the pathogenesis of murine respiratory mycoplasmosis in rats. Since LEW rats are more susceptible to this disease than F344 rats are, these two strains were used to examine a possible association between disease severity and the level of nonspecific lymphocyte stimulation by mitogens, including M. pulmonis membrane preparations. F344 and LEW spleen, lung, blood, and lymph node lymphocytes were exposed to various mitogens. LEW lymphocytes gave a significantly higher response to mitogenic stimulation, regardless of their anatomical source. These differences in lymphocyte responsiveness were primarily due to differences within the nonadherent cell population. Significantly higher numbers of W3/25+ (T helper) cells were found in LEW lymphoid populations, whereas no difference was found in MRC OX-8+ (T suppressor/cytotoxic) cells. These data suggest an association between disease severity and host responsiveness to nonspecific stimuli.     

Interference in SV40 DNA infections: a possible basis for cellular competence.

At the restrictive temperature, DNA from temperature-sensitive mutants of simian virus 40 (SV40) (in the A or B/C genes) interferes with plaque formation by wild-type SV40 DNA. This interference occurs early in the first cycle of infection. Nonhomologous DNA also can interfere with SV40 DNA infection. The mode of interference by ts SV40 DNAs and nonhomologous DNAs appears to be the same. In conjunction with other observations the interference by nonhomologous DNA and the similarity of interference by tsA DNA and tsB DNA suggest that interference does not require expression of any viral gene product. Since interference is observed even when the infections by interfering DNA and wild-type DNA are separated in time, interference must occur after the DNAs interact with cells. Furthermore, the different efficiencies with which structurally similar DNAs (SV40, PM2 and φX174 replicative form) interfere indicate that interference depends at least in part on nucleotide sequence. Those two observations suggest that interference is an intracellular, perhaps nuclear, phenomenon. The possible relevance of this interference phenomenon to observations on cellular competence for SV40 DNA infections is discussed.     

Distribution of glutathione S-transferase isoenzymes in human kidney: basis for possible markers of renal injury.

To determine whether the tissue distribution of glutathione S-transferase (GST) isoenzymes could define the precise nature of renal injury, 13 adult kidneys were studied, using specific antibodies raised against purified isoenzymes. Basic GST stained strongly proximal convoluted tubules and some medullary tubules; acidic GST stained strongly distal convoluted tubules and medullary tubules; neutral GST stained similarly to acidic GST, but weaker, and microsomal GST stained glomerular and interstitial endothelium and collecting ducts deep in the medulla, although there was considerable variation in staining intensity among cases. It is suggested that the measurement of these isoenzymes in serum and urine may help to elucidate the localisation of tissue damage, which may be particularly valuable in patients with cyclosporine toxicity following renal transplantation.     

The clara cell: A comparative ultrastructural study in mammals

Clara cells in the terminal bronchioles of mouse, rat, rabbit, calf and human were compared by light, transmission and scanning microscopy, and species-differences were clearly present. Mouse Clara cells were most numerous and mouse and rabbit Clara cells had large dense mitochondria. Rabbit and calf had glycogen in Clara cells and rat Clara cells had the most variability in secretory granules, some of which had a crystalline structure. Calf Clara cells had deeply indented nuclei. Human Clara cells had the most prominent nucleoli and lacked smooth endoplasmic reticulum, which was a prominent feature of most other species. No evidence of apical extrusion or apocrine secretion of Clara cell secretory granules was observed.     

Strain differences influence murine pulmonary responses to Stachybotrys chartarum

When the fungus Stachybotrys chartarum is inhaled, its mycotoxins may cause lung injury and inflammation. The severity of human responses to S. chartarum in both occupational and home settings varies widely. To explore these differences, we intratracheally instilled C3H/HeJ, BALB/c, and C57BL/6J mice with S. chartarum spores suspended in saline. One day later, the mice were humanely killed, bronchoalveolar lavage (BAL) was performed, and biochemical and cellular indicators of lung injury and inflammation were measured. BALB/c mice showed the highest myeloperoxidase activity, albumin and hemoglobin levels, and neutrophil numbers in their BAL among the three strains. BALB/c was the only strain to show significant increases in keratinocyte-derived cytokine (KC), monocyte chemotactic protein (MCP)-1, MCP-3, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, MIP-1gamma, MIP-2, RANTES, IL-1alpha, IL-1beta, IL-3, IL-6, IL-18, leukemia inhibitory factor, macrophage colony-stimulating factor, and TNF-alpha. A model of allergen-induced airway inflammation was examined to assess whether underlying allergic inflammation might contribute to increased susceptibility to S. chartarum-induced pulmonary inflammation and injury. Surprisingly, in BALB/c mice, ovalbumin-induced airway inflammation produced a protective effect against some S. chartarum-induced pulmonary responses. This is the first report of mammalian strain differences affecting responses to S. chartarum. These responses differ from those reported for LPS and other fungi. Analogous underlying genetic differences may contribute to the wide range of sensitivity to Stachybotrys among humans.     

Strain differences in mouse cellular responses to Mycobacterium lepraemurium and BCG subcutaneous infections. I. Analysis of cell surface phenotype in local granulomas.

C57BL/6, BALB/c and CBA mice were subcutaneously infected with either Mycobacterium lepraemurium (MLM) or BCG, and studied for bacillary growth, granuloma size of infected footpads and draining lymph nodes (DLN), and DLN cell surface phenotype. Whereas, BCG-infected mice controlled the infection and developed early and large granulomas, MLM-infected mice exhibited major strain variations in their resistance to the infection, as well as in the granuloma size and kinetics. C57BL/6 mice, highly resistant, displayed early and regressive granulomas; BALB/c mice showed lower resistance and early granulomas that grew continuously; CBA mice, highly susceptible, developed late, soft, phagocyte-rich granulomas. Important strain differences in lymph node lymphocyte subset distribution could be observed prior to any infection: C57BL/6 mice displayed higher B cell percentages than both of the other strains and BALB/c mice showed the highest CD4/CD8 ratios, followed by CBA and C57BL/6 mice. BCG and MLM infections both induced similar changes of these parameters in all three strains: that is a decrease of the B cell percentage and a decrease of the CD4/CD8 ratio, and the strain differences observed in uninfected mice persisted. On the other hand, DLN cells stimulated by the infecting bacillus and interleukin 2 also displayed an increase of the CD8 T cell percentage as compared with normal lymph node cells, but this phenomenon was much less pronounced in BALB/c mice, whether infected by MLM or BCG, and in MLM-infected CBA mice, than in BCG- or MLM-infected C57BL/6 (B6) mice. Thus the ability of C57BL/6 mice to generate an early and persistent CD8 T cell response to mycobacteria may contribute to their resistance to MLM.     

Inhibition of cellular responses to insulin in a rat liver cell line. A role for PKC in insulin resistance

The initial response of liver cells to insulin is mediated through exocytosis of Cl⁻ channel-containing vesicles and a subsequent opening of plasma membrane Cl⁻ channels. Intracellular accumulation of fatty acids leads to profound defects in metabolism, and is closely associated with insulin resistance. It is not known whether the activity of Cl⁻ channels is altered in insulin resistance and by which mechanisms. We studied the effects of fatty acid accumulation on Cl⁻ channel opening in a model liver cell line. Overnight treatment with amiodarone increased the fat content by ∼2-fold, and the rates of gluconeogenesis by ∼5-fold. The ability of insulin to suppress gluconeogenesis was markedly reduced indicating that amiodarone treatment induces insulin resistance. Western blot analysis showed that these cells express the same number of insulin receptors as control cells. However, insulin failed to activate exocytosis and Cl⁻ channel opening. These inhibitory effects were mimicked in control cells by exposures to arachidonic acid (15 μ m ). Further studies demonstrated that fatty acids stimulate the PKC activity, and inhibition of PKC partially restored exocytosis and Cl⁻ channel opening in insulin-resistant cells. Accordingly, activation of PKC with PMA in control cells potently inhibited the insulin responses. These results suggest that stimulation of PKC activity in insulin resistance contributes to the inhibition of cellular responses to insulin in liver cells.     

Humoral and cellular immune responses in Aspergillus fumigatus pulmonary disease.

This study was designed to evaluate immunologic differences between aspergilloma (A) and allergic bronchopulmonary aspergillosis (ABPA), comparing the results to atopic and nonatopic control subjects. Humoral studies included skin tests with common inhalant antigens and Aspergillus fumigatus. Total and specific IgE and other immunologlobulin levels and serum precipitins were evaluated against A. fumigatus. Cellular immunity was studied with routine skin testing and phytohemaqglutinin-induced lymphocyte blast transformation. Antigen-induced blast transformation was also carried out with the use of serial dilutions of A. fumigatus. All patients with ABPA were atopic and had marked elevations of IgE. None of the patients were atopic and they had normal IgE levels. Immediate and late skin reactivity to A. fumigatus was low in control and A groups but high in 2 patients with ABPA. IgG antibody against A. fumigatus was generally greater in the ABPA group. Both ABPA and A had serum precipitating antibody against A. fumigatus. The atopic controls had elevated IgE levels and immediate skin test reactivity to A. fumigatus, and one also had weak serum precipitins against A. fumigatus. IgE antibody against A. fumigatus was generally higher in ABPA than A. ABPA and A patients had elevated stimulation indices (SI) to A. fumigatus. No stimulation could be detected with cells from control subjects. This study indicates that both T and B cell sensitization may play a role in the development of or as a response to aspergillus-related pulmonary disease.     

Stability of individual differences in cellular immune responses to two different laboratory tasks

To explore the stability of immune reactivity across laboratory tasks, we correlated enumerative and functional lymphocyte responses to a speech task and a mental arithmetic task, delivered on the same occasion of testing in 31 healthy undergraduates. Both tasks were associated with an increase in peripheral CD8+ and CD56+ cell populations, and a decrease in proliferative response to phytohemagglutinin (PHA) and ratio of CD4:CD8 cells. Intertask correlations were significant for the magnitude of change in proliferative responses at two different concentrations of PHA, r = 0.76, p < .0001 and r = 0.46, p < .05, and in numbers of circulating CD56+ cells, r = 0.46, p < .005. Concomitant heart rate and systolic blood pressure responses also correlated significantly over the two experimental tasks (heart rate: r = 0.52 and systolic blood pressure: r = 0.58. ps < .0005). These data provide initial evidence that interindividual variability of some cellular immune responses is moderately reproducible across different stimulus conditions, providing further evidence that it may denote a stable individual difference.     

A possible neurophysiological basis for psychological pain

There is some evidence that the anterior cingulate cortex (ACC) contains nociceptive neurons, and other neurons which respond to conditioned aversive stimuli. It is not implausible that nociceptive input and conditioned aversive input converge onto common neurons in the ACC. Following from this hypothesis, the psychological pain which occurs in circumstances that arouse disgust or aversion may involve the same mechanisms that give rise to referred pain.     

Heterogeneity in cellular and humoral immune responses against Toxoplasma gondii antigen in humans

Protection against Toxoplasma gondii in infected patients is mainly attributed to cellular immunity. We here attempt to improve the characterization of the proteins that induce cellular immunity in naturally infected patients. Cellular immunity was evaluated by flow cytometry after 7 days of blood culture from 31 chronically T. gondii infected and 8 noninfected pregnant women, in the presence of soluble T. gondii antigen (ST-Ag) or fractionated proteins from ST-Ag, separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Blood cultures from infected patients with ST-Ag induced 39.5 +/- 12.7% of activated (CD25+) CD4+ T cells using flow cytometry. This contrasts with the absence of activated CD4+ T cells after either culture with PBS or in blood cultures from noninfected women. The protein fraction between 21 and 41.9 kD induced the highest response (14.7 +/- 10.0%). Blood samples from 20 infected and 5 uninfected women were cultured in presence of 12 protein subfractions of 2-208 kD. The highest frequencies of response among infected patients were seen with fractions (Fr) 26-31.9 kD (C.I. 85-100%) and Fr 32-36.9 kD (C.I. 77-100%). Although we note a good concordance between cellular and humoral response, Western blot analysis of ST-Ag does not completely predict the panel of proteins recognized by cellular immunity. Two-dimensional separation of the ST-Ag revealed more than 200 protein spots in these fractions. However, only two proteins in the 20-40 kD range induced a significant humoral response. Further studies are necessary to determine which proteins in the Fr 26-31.9 kD and 32-36.9 kD are superior immunogens for cellular responses.     

Interferon response heterogeneity: activation of a pro-inflammatory response by interferon alpha and beta. A possible basis for diverse responses to interferon beta in MS

Interferon gamma (IFN-gamma) stimulates the (pro-inflammatory) type II interferon receptor and is known to exacerbate multiple sclerosis (MS). In contrast, IFN-alpha and IFN-beta are ligands for the (anti-inflammatory) type I interferon receptor and are beneficial in some (but not all) patients with MS. Should IFN-beta elicit a type-II-like pro-inflammatory response, the beneficial effects might be attenuated. These studies were undertaken to test this possibility with the use of quinolinic acid (QUIN) formation as a measure of type II receptor activation. In normal human macrophage cultures, IFN-gamma was the most potent stimulus for QUIN formation. Generally, IFN-beta and IFN-alpha were less potent. However, an unexpected inter-patient variability was observed. In some subjects, IFN-alpha was more potent than IFN-beta. In other subjects, IFN-beta was more potent than IFN-alpha. The present data demonstrate an inter-subject variability for QUIN production following exposure to the interferons. MS patients who demonstrate a pro-inflammatory response to IFN-beta (e.g., increased QUIN) may be less likely to benefit from this therapy.     

Immunocytochemical analysis of cellular responses to BCG.

The study reported here was performed to find out whether changes in the number of mycobacteria in various organs of BCG-infected mice can be related to changes in the phenotype of monocytes, macrophages and lymphocytes in the blood, various tissues, and peritoneal cavity and to the formation of granulomas in the spleen, liver and lungs. The relative amounts of various antigens on the leukocytes were assessed semi-quantitatively after immunocytochemical detection of the binding of monoclonal antibodies. Granuloma formation was determined after immunocytochemical staining of cells in sections of liver and lung tissue with a monoclonal antibody against the common leukocyte antigen and in sections of the spleen with a monoclonal antibody against the Mac-2 antigen. The results showed that during the first week of infection the number of BCG in spleen, liver and lungs declined considerably. Multiplication of mycobacteria during the second week of infection was associated with decreased expression of antigen F4/80 and increased expression of Ia antigen and Mac-2 antigen by blood monocytes and macrophages. Reduction of the numbers of BCG in the spleen and liver during the third week after i.v. injection of BCG and in lungs during the fourth week of the infection was found to be correlated with the degree of granuloma formation in these organs. After intravenous injection of killed BCG no changes were observed in the phenotype of monocytes and the macrophages in spleen, liver, lungs and peritoneal cavity. These mice showed considerably less granuloma formation than BCG-infected mice. The present results indicate that live but not killed mycobacteria induce macrophage activation.     

Sensitivity to androgen. A possible factor in sex differences in the immune response

In strains of mice with high or low sensitivity to androgen, previous studies demonstrated that sex differences in the levels of certain Igs occurred only in the high androgen responder (HAR) strain, but not in the low androgen responder (LAR) strain. HAR C57L/J males, whether intact or castrated, had lower levels of IgM and IgG2 than C57L/J females, and lower levels of IgM and IgG2 than LAR A/J mice (Cohn & Hamilton, 1976). The current study indicates that the pattern of low immune response characteristic of HAR males in non-specific responses also occurs in response to three different antigens and is evident in another HAR strain, the RF/J.

Results show that in response to type 3 pneumococcal polysaccharide (SIII), HAR C57L/J males consistently produced lower levels of antibody than C57L/J females, whereas LAR A/J males and females produced similar levels of anti-SIII. HAR C57L/J males also produced significantly lower levels of anti-SIII than LAR A/J males following restricted doses of SIII (50 ng). Altering the concentration of circulating testosterone in HAR C57L/J males had no effect on their anti-SIII responses. In assays of another pair of HAR and LAR strains, the RF/J and 129/J, HAR RF/Js had significantly lower anti-SIII responses than LAR 129/Js. In response to bovine serum albumin (BSA), HAR C57L/J mice showed sex differences in anti-BSA responses both 14 and 21 days after immunization, whereas HAR A/J mice showed sex differences on day 14 only, before peak responses developed. Of all mice assayed, however, HAR C57L/J males had the lowest levels of anti-BSA on both days. When strains differing in sensitivity to androgen and H-2 type were assayed for antibody to bovine gamma-globulin (B-IgG), RF/J females produced comparatively high antibody responses as expected for H-2^k strains, but HAR RF/J males produced the lowest levels of antibody of all mice assayed.

The results of these studies support and extend earlier observations of an apparent correlation in male mice between high sensitivity to androgen and poor immune responsiveness.

     

Consistent sex differences in cortisol responses to psychological stress.

In four independent studies, sex differences in cortisol responses to psychological stress were investigated in healthy adolescents and adults (total n = 153). Public speaking and mental arithmetic in front of an audience (Studies 1-3) reliably induced increases in free cortisol levels in both sexes with 2- to 4-fold increases above baseline levels. Mean cortisol responses were 1.5- to 2-fold higher in men compared with women. In Study 3, cortisol profiles were additionally investigated after human corticotropin-releasing hormone (h-CRH) and bicycle ergometry until exhaustion. Here, both sexes showed very similar adrenocortical responses. Furthermore, men showed elevated cortisol levels in anticipation of the psychological stress situation without actually having to perform the tasks (Study 4). Under this condition cortisol concentration was unchanged or decreased in women. From these data we conclude that the observed sex difference does not reflect an overall lower responsiveness of the female adrenal cortex. Although these studies do not provide conclusive data, we suggest sex differences in cognitive and/or emotional responses to distressing psychosocial situations which in turn may influence cortisol secretion.