Peritoneal interleukin-10 increases with decrease in activated CD4+ T lymphocytes in women with endometriosis

This study was performed to determine whether peritoneal T cells are suppressed in the CD4+ or CD8+ T cell subpopulation and whether they are Th1 or Th2 predominant in women with endometriosis. Immune cells in the peritoneal fluid (PF) were obtained from women undergoing laparoscopy for endometriosis or tubal ligation. Three-colour flow cytometry was utilized for immunophenotyping of peritoneal fluid mononuclear cells (PFMC). Concentrations of interleukin (IL)-4, IL-5 and interferon-gamma (IFN-gamma) produced by PFMC with and without mitogen stimulation and concentrations of IL-10 and IL-12 were measured in PF. The peritoneal T lymphocytes were predominantly of the Th1 type that produced much more IFN-gamma but less IL-4 or IL-5 in women with or without endometriosis. The decrease in peritoneal lymphocytes was significant in the HLA-DR+ CD4+ CD3+ subpopulation and the concentrations of peritoneal IL-10 and IL-12 were significantly elevated in women with early stage endometriosis. There was impaired IL-5 production by PFMC after phytohaemagglutinin stimulation in women with advanced stage endometriosis. We concluded that the activated peritoneal CD4+ Th1 cells from the women with endometriosis were decreased in number. The suppression of these T cells may be due to the elevation of IL-10 and IL-12 in the peritoneal fluid.     

Characterization of circulating CD4+ CD8+ lymphocytes in healthy individuals prompted by identification of a blood donor with a markedly elevated level of CD4+ CD8+ lymphocytes

During flow cytometric analysis of lymphocytes from healthy donors, we identified a donor (donor A) with 22% CD4+ CD8+ cells (versus values of < 4% for 65 other controls). To determine if CD4+ CD8+ cells from donor A and other controls were similar, we first defined the phenotypic profile of control CD4+ CD8+ cells. Enriched CD4+ CD8+ cell populations for 10 controls were prepared by a two-step positive selection scheme with anti-CD4-coated magnetic beads and anti-CD8-coated culture flasks; the selected population averaged 69% CD4+ CD8+ cells and 31% CD4+ CD8- cells. For all 10 controls, two subsets of CD4+ CD8+ cells, CD4dim CD8bright and CD4bright CD8dim, were observed. Phenotypic profiles of these two CD4+ CD8+ subsets were defined by pairing anti-CD8 with other monoclonal antibodies, and the profiles were compared with each other and with those of CD4+ CD8-, CD4- CD8bright, and CD4- CD8dim cells. CD8bright and CD4bright CD8dim cells differed in their proportions of CD62-L+ cells and in their levels of CD11a and CD2 expression. Both CD4+ CD8+ subsets resembled CD4+ CD8- cells in CD45RA, CD45RO, and CD25 expression; the comparable CD- CD8+ cells in CD62-L expression; and CD4- CD8bright cells in CD11b, CD11b, CD16/56, and CD28 expression. CD38 expression in both CD4+ CD8+ subsets was decreased compared with those of other cell subsets. Whereas control CD4+ CD8+ cells averaged 33% CD4dim CD8bright, CD4+ CD8+ cells from donor A were > 90% CD4dim CD8bright. Donor A CD4dim CD8bright cells exhibited proportional decreases in CD25 and CD62-L expression and increases in CD11b and CD54 expression compared with those of control CD4dim CD8bright cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Functional characterization of porcine CD4+CD8+ extrathymic T lymphocytes

The porcine immune system is unique in that the expression of CD4 and CD8 antigens defines four subpopulations of resting, extrathymic (CD1-) T lymphocytes. In addition to CD4-CD8+ and CD4+CD8- T lymphocytes, CD4-CD8- and CD4+CD8+ lymphocyte subpopulations are prominent in blood as well as in lymphoid tissues. In the present study, a functional comparison was made between CD4+CD8- and CD4+CD8+ T lymphocyte subpopulations. In a primary in vitro immune response against alloantigenic stimulator cells, both subpopulations proliferated without significant differences in their reactivity. Different results were obtained when analyzing the antigen-specific functions of the two CD4+ subpopulations in a secondary response against recall viral antigen; these experiments were performed with T lymphocytes from pseudorabies virus-immunized pigs. The proliferative response against viral antigens could be assigned to the CD4+CD8+ subpopulation, whereas the CD4+CD8- subpopulation remained nonreactive. Further analyses of the virus-specific in vitro immune response revealed a major histocompatibility complex (MHC) class II restricted helper T lymphocyte reaction involving CD4 but not CD8 molecules as restriction elements. Taken together, these results demonstrate that only the extrathymic CD4+CD8+ T lymphocyte subpopulation of swine contains MHC class II-restricted antigen-specific memory T helper cells.     

CD16-expressing CD8alpha alpha+ T lymphocytes in the intestinal epithelium: possible precursors of Fc gammaR-CD8alpha alpha+ T cells

T lymphocytes normally express their Ag receptors in association with the CD3 proteins, which include CD3zeta. In CD3zeta eta(null) mice thymic and peripheral T lymphocytes do not express the TCR/CD3 complex on their surface due to retention in the endoplasmic reticulum of the remaining polypeptide chains. However, intestinal intraepithelial lymphocytes (iIEL) of CD3zeta eta(null) mice do express surface TCR, because the Fc epsilonRI gamma chain replaced the CD3zeta chain in the TCR/CD3 complex. Here we report that in a subset of CD8alpha alpha+ iIEL the presence of the Fc epsilonRI gamma chain could be accounted for by the surface expression of the Fc gammaRIII(CD16) complex. Because in wild-type (wt) mice only CD16+ iIEL coexpressed Fc epsilonRI gamma and CD3zeta, we concluded that the presence of Fc epsilonRI gamma was dictated by its required participation of CD16 complex. CD8alpha alpha+ iIEL bearing CD16 and B220 were also detected in the intestinal mucosa of RAG-2(null) mice from 12 days after birth onward. Two independent experimental settings were used in an attempt to demonstrate that CD16+ iIEL matured into CD16- T cells. First, in the RAG-2(null) mice, iIEL responded to in vivo administration of an anti-CD3epsilon mAb by progression to a more mature stage of development, characterized by a loss of CD16 and B220. Secondly, a conversion to CD16- iIEL occurred upon transfer of wt CD16+ iIEL into RAG-2(null) mice. We conclude from these experiments that in both RAG-2(null) and wt mice, a precursor/progeny relationship may exists between CD16+ B220+ CD8alpha alpha+ and CD16- B220- CD8alpha alpha+ iIEL.     

Natural killer cell cytotoxicity and paternal lymphocyte immunization in women with recurrent spontaneous abortions

Although cardiac function is depressed during endotoxic shock, it remains controversial whether the ventricular contractility and structure are altered during sepsis. To resolve this issue, rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). At 2, 5, and 10 h after CLP (i.e., the early, hyperdynamic stage of sepsis) or 20 h after CLP (the late, hypodynamic stage of sepsis, based on the depressed tissue perfusion), in vivo left ventricular contractility parameters such as maximal rate of the left ventricular pressure increase (+dP/dtmax) and decrease (-dP/dtmax), maximal rate of "pressure-normalized" change in ventricular pressure (dP/dtmax/P), and ventricular peak systemic pressure were determined using a Digi-Med Heart Performance Analyzer. In additional groups of animals, ultrastructure of the cardiac muscle in the left ventricle was examined at 5, 10, or 20 h after CLP, using a transmission electron microscope. The results indicate that +dP/dtmax and dP/dtmax/P increased significantly at 2-10 h after CLP. The values of -dP/dtmax and ventricular peak systemic pressure increased significantly at 2 and 5 h after the onset of sepsis, respectively. These in vivo ventricular contractility parameters, however, were not significantly different from shams at 20 h after CLP. Ultrastructural examination showed that enlarged T-tubules were prominent during the hyperdynamic stage of sepsis, which was correlated with the increased cardiac contractility. Although focal and moderate hypertrophy as well as expanded intermyocyte junctions could be observed occasionally, myocardial cells did not appear to be compromised at 20 h after CLP. Thus, the transition from the hyperdynamic to hypodynamic circulation during sepsis does not appear to be due to any depression in myocardial function because cardiac contractility and structure are not compromised even during the late, hypodynamic stage of sepsis. However, further investigation is required to determine whether cardiac function is depressed at the terminal stage of polymicrobial sepsis.     

Increase in endocervical CD4 lymphocytes among women with nonulcerative sexually transmitted diseases

BACKGROUND AND PURPOSE: Stroke-prone spontaneously hypertensive rats (SHRSP) subjected to high sodium intake develop severe hypertension, cerebral edema, and proteinuria, culminating in organ damage and early death. MRI, which can be applied serially, provides the unique opportunity to study temporal and quantitative relations between these changes and whether diminution of sodium intake can attenuate established cerebral edema. METHODS: SHRSP were subjected to 1% NaCl in drinking water. Cerebral MRI, proteinuria and systolic blood pressure (SBP) were measured serially. After detection of cerebral edema (T2-weighted MRI), 6 rats were killed for histology, to confirm the diagnosis of cerebral edema. The others were followed up for 7 more days while salt loading was continued (n = 10, group 1) or after sodium intake was normalized (n = 7, group 2). RESULTS: SHRSP invariably developed cerebral edema in 30 days (range, 8 to 54 days). At this point neurological signs were absent in 16 of 23 rats. SBP rose until 1 week before detection of cerebral edema, and then stabilized at approximately 265 mm Hg. Proteinuria invariably preceded cerebral edema, with a concentration exceeding 40 mg/d predicting development of cerebral edema in 9 days (range, 3 to 15 days). There was linear correlation (R=.62, P<.0001) between proteinuria and cerebral edema (pixels with an intensity above a defined threshold). Rats in group 1 showed an increase in cerebral edema (from 5.8+/-1.1% to 12.5+/-2.8%; P<.05), and proteinuria remained high (from 305+/-44 to 338+/-29 mg/d); and 2 died spontaneously. Rats in group 2 showed no significant change in edema (from 4.9+/-0.5% to 6.9+/-1.3%) but a marked fall in proteinuria (from 294+/-24 to 119+/-10 mg/d; P<.05), both significantly different from group 1 (P<.05); all survived. SBP remained unaltered in both groups. CONCLUSIONS: Our data establish MRI as a sensitive method for detection of cerebral edema, often prior to neurological signs, in SHRSP. Proteinuria predicts cerebral edema, and these two variables, both obtained noninvasively, are quantitatively related. Moreover, in SHRSP normalizing sodium intake after salt loading attenuates development of cerebral edema and reduces proteinuria.     

Stimulation of protective CD8+ T lymphocytes by vaccination with nonliving bacteria

Infectious diseases caused by intracellular microbes are responsible for major health problems, and satisfactory control will ultimately depend on efficient vaccination strategies. The general assumption is that activation of protective immune responses against intracellular microbes dominated by CD8+ T cells are achieved only by live vaccines. In contrast, we here demonstrate stimulation of protective immunity in mice against the intracellular pathogen Listeria monocytogenes by vaccination with heat-killed listeriae. Vaccine-induced immunity comprised cytolytic and interferon gamma-producing CD8+ T lymphocytes. CD8+ T cells from vaccinated donor mice transferred protection against listeriosis. Moreover, vaccination with heat-killed listeriae induced production in CD4+ T-cell-deficient, H2-A beta gene-disrupted mutant mice. We conclude that antigens from killed listeriae are introduced into the major histocompatibility complex class I pathway and thus are recognized by CD8+ T cells. The practicability of killed vaccines against human infectious diseases therefore should be reevaluated.     

Signaling through a CD3 gamma-deficient TCR/CD3 complex in immortalized mature CD4+ and CD8+ T lymphocytes

The biologic role of each CD3 chain and their relative contribution to the signals transduced through the TCR/CD3 complex and to downstream activation events are still controversial: they may be specialized or redundant. We have immortalized peripheral blood CD4+ and CD8+ T lymphocytes from a human selective CD3 gamma deficiency using Herpesvirus saimiri. The accessibility of the mutant TCR/CD3 complex to different Abs was consistently lower in immortalized CD8+ cells when compared with CD4+ cells, relative to their corresponding CD3 gamma-sufficient controls. Several TCR/CD3-induced downstream activation events, immediate (calcium flux), early (cytotoxicity and induction of surface CD69 or CD40L activation markers or intracellular TNF-alpha) and late (proliferation and secretion of TNF-alpha), were normal in gamma-deficient cells, despite the fact that their TCR/CD3 complexes were significantly less accessible than those of controls. In contrast, the accumulation of intracellular IL-2 or its secretion after CD3 triggering was severely impaired in gamma-deficient cells. The defect was upstream of protein kinase C activation because addition of transmembrane stimuli (PMA plus calcium ionophore) completely restored IL-2 secretion in gamma-deficient cells. These results suggest that the propagation of signals initiated at the TCR itself can result in a modified downstream signaling cascade with distinct functional consequences when gamma is absent. They also provide evidence for the specific participation of the CD3 gamma chain in the induction of certain cytokine genes in both CD4+ and CD8+ human mature T cells. These immortalized mutant cells may prove to be useful in isolating cytosolic signaling pathways emanating from the TCR/CD3 complex.     

Immunophenotypic profiles of peripheral blood lymphocytes in women with recurrent pregnancy losses and in infertile women with multiple failed in vitro fertilization cycles

BACKGROUND: Our aims were to investigate the question as to whether the adenoma-carcinoma sequence also applies to the papilla of Vater and to determine the frequency with which a tumour of the papilla of Vater, diagnosed histologically as containing portions of an adenoma, already contains adenocarcinoma elsewhere. METHODS: A retrospective analysis was carried out of the forceps, snare biopsy, and excised specimens obtained from the papilla of Vater in 559 patients, including 210 patients with the primary diagnosis of carcinoma and 110 patients with the diagnosis of 'portions of an adenoma'. Comparisons were made of the age distribution of patients with adenoma and those with carcinoma, and the frequency of residual adenoma in a carcinoma as a function of degree of malignancy, T stage, and UICC stage. A follow-up examination of the patients with the primary diagnosis 'parts of an adenoma of the papilla of Vater' was performed. RESULTS: The average age of the patients with the final diagnosis adenoma was 65.2 years, and that of the carcinoma patients 73.0 years. Residual adenoma was found in 54.9% of the 51 surgical specimens and in 31.7% of the 159 biopsy specimens obtained from carcinomas. The frequency of residual adenoma in carcinomas decreased statistically significantly with increasing T stage and degree of malignancy. The follow-up examination of the 110 patients with the primary biopsy diagnosis parts of an adenoma of the papilla of Vater showed unequivocal results in 80 cases. Only in 39.7% of these cases was the primary diagnosis adenoma confirmed, whereas in 60.25%, further histologic examination showed a carcinoma. CONCLUSIONS: An analysis of our results, together with those reported in the literature, indicates that the adenoma-carcinoma sequence also applies to the papilla of Vater and that, in a high percentage of patients with the histologic diagnosis 'parts of an adenoma, other regions of the tumour already contain a carcinoma.     

CD8+CD103+ T cells analogous to intestinal intraepithelial lymphocytes infiltrate the pancreas in chronic pancreatitis

OBJECTIVE: Chronic pancreatitis is a painful chronic inflammatory disease of the exocrine pancreas that is associated with the replacement of functional parenchyma by extended fibrosis and with a massive infiltration of T lymphocytes. However, to date further characterization of infiltrating T cells in chronic pancreatitis has not been undertaken. METHODS: Using the novel method of multiepitope imaging with fluorochrome-tagged specific monoclonal antibodies, which allows the simultaneous localization and characterization of T cells in tissues, we analyzed the distribution and phenotypes of T cells infiltrating the pancreas in chronic pancreatitis. RESULTS: The mean CD4:CD8 ratio in 10 cases of chronic pancreatitis was 2.4:1. In order of decreasing frequency, the following markers were observed: CD45RO, CD18, TCRgammadelta, and CD103. The lymphocytes, especially of the CD4+ subset, were found mainly in the fibrous stroma, but T cells were also observed periductally. A T-cell subset bearing the phenotype CD8+CD103+, analogous to intestinal intraepithelial lymphocytes, was found intracalating between the cells of the ductal epithelium. CONCLUSIONS: Phenotyping of the T lymphocytes in chronic pancreatitis supports the concept of the involvement of cell-mediated cytotoxicity in the pathogenesis of this disease. In addition, intraepithelial lymphocytes were found interspersed between the ductal epithelial cells, pointing to a role of this T-cell subset as a first-line defense against deleterious epithelial events in chronic pancreatitis.     

Monitoring oxypurines levels in women with pregnancy induced hypertension and in women with physiological pregnancy

We report on catamnestic and clinical results of a 18-24 month follow-up study of 65 alcohol-dependent patients who in 1992-1994 took part in an 8-month outpatient treatment programme. The psychotherapeutic concept of this treatment facility is described. 51 of the 65 patients who had participated in the programme could be subsequently personally interviewed, 7 patients refused to take part, 6 could not be reached and 1 had died. 40 of the 51 patients had properly completed the outpatient treatment. Assuming that all patients who could not be interviewed or refused, were relapsers the abstinence rate was found to be 48% (n = 31). Although selective factors may contribute to this result, the clinical findings so far seem to indicate that outpatient treatment for alcoholics is a promising new therapeutic approach in the treatment of alcoholism. Further studies are needed to assess the possible benefits and the indications for this outpatient treatment in greater detail.     

Control of viremia in simian immunodeficiency virus infection by CD8+ lymphocytes

Clinical evidence suggests that cellular immunity is involved in controlling human immunodeficiency virus-1 (HIV-1) replication. An animal model of acquired immune deficiency syndrome (AIDS), the simian immunodeficiency virus (SIV)-infected rhesus monkey, was used to show that virus replication is not controlled in monkeys depleted of CD8+ lymphocytes during primary SIV infection. Eliminating CD8+ lymphocytes from monkeys during chronic SIV infection resulted in a rapid and marked increase in viremia that was again suppressed coincident with the reappearance of SIV-specific CD8+ T cells. These results confirm the importance of cell-mediated immunity in controlling HIV-1 infection and support the exploration of vaccination approaches for preventing infection that will elicit these immune responses.     

Maturation of human neonatal CD4+ and CD8+ T lymphocytes into Th1/Th2 effectors

The increased susceptibility of neonates to infections has been ascribed to the immaturity of their immune system. More particularly, T cell-dependent responses were shown to be biased towards a Th2 phenotype. Our studies on the in vitro maturation of umbilical cord blood T cells suggest that the Th2 bias of neonatal response cannot be simply ascribed to intrinsic properties of neonatal T cells. Phenotypically, neonatal CD4+ T cells are more immature than their adult CD45RO-/RA+ naive counterparts and they contain a subset (10-20%) of CD45RO-/RA+ CD31- cells which is very low in adults and displays some unique functional features. The activation and maturation of neonatal CD4+ T cells is particularly dependent upon the strength of CD28-mediated cosignal which dictates not only the cytokine profile released upon primary activation but also the response to IL-12. Activation of adult as well as neonatal CD4+ T cells in the context of low CD28 costimulation yields to the production of low levels of only one cytokine, i.e. IL-2. In contrast, strong CD28 costimulation supports the production of high levels of type 1 (IL-2, IFN gamma and TNF beta) and low levels of type 2 (IL-4 and IL-13) cytokines by neonatal T cells. The low levels of naive T cell-derived IL-4 are sufficient to support their development into high IL-4/IL-5 producers by an autocrine pathway. The ability of IL-12 to prime neonatal CD4+ T cells for increased production of IL-4 (in addition to IFN gamma) is observed only when CD28 cosignal is minimal. Under optimal activation conditions (i.e. with anti-CD3/B7.1 or allogenic dendritic cells) the response and the maturation of neonatal and adult naive T cells are similar. Thus the Th2 bias of neonatal immune response cannot be simply ascribed to obvious intrinsic T cell defect but rather to particular conditions of Ag presentation at priming. Unlike CD4+ T cells, neonatal CD8+ T cells strictly require exogenous IL-4 to develop into IL-4/IL-5 producers. Most importantly, anti-CD3/B7-activated neonatal CD8 T cells coexpress CD4 as well as CCR5 and CXCR4 and are susceptible to HIV-1 infection in vitro.     

Productive infection of neonatal CD8+ T lymphocytes by HIV-1

CD8+ T lymphocytes confer significant but ultimately insufficient protection against HIV infection. Here we report that activated neonatal CD8+ T cells can be productively infected in vitro by macrophage-tropic (M-tropic) HIV-1 isolates, which are responsible for disease transmission, whereas they are resistant to T cell-tropic (T-tropic) HIV strains. Physiological activation of CD8-alpha/beta+ CD4- T cell receptor-alpha/beta+ neonatal T cells, including activation by allogeneic dendritic cells, induces the accumulation of CD4 messenger RNA and the expression of CD4 Ag on the cell surface. The large majority of anti-CD3/B7.1-activated cord blood CD8+ T cells coexpress CD4, the primary HIV receptor, as well as CCR5 and CXCR4, the coreceptors used by M- and T-tropic HIV-1 strains, respectively, to enter target cells. These findings are relevant to the rapid progression of neonatal HIV infection. Infection of primary HIV-specific CD8+ T cells may compromise their survival and thus significantly contribute to the failure of the immune system to control the infection. Furthermore, these results indicate a previously unsuspected level of plasticity in the neonatal immune system in the regulation of CD4 expression by costimulation.     

Differential usage of T cell receptor V gene segments in CD4+ and CD8+ subsets of T lymphocytes in monozygotic twins

The TCR confers immunity by the specific recognition of foreign Ag peptides in the context of self-MHC molecules. The mechanisms controlling TCR selection and repertoire generation are not clearly understood and seem to occur in an apparently random, (self) Ag-driven manner. To address the question to what extent the TCR repertoire is randomly shaped or genetically predetermined, we have analyzed the alpha beta TCR repertoire of the CD4+ and CD8+ subsets of peripheral blood lymphocyte cultures of monozygotic twins by using the polymerase chain reaction technique with TCR V region gene family-specific oligonucleotide primers. Our studies demonstrate that there is high concordance in the overall patterns of V gene usage within a pair of twins, particularly in V beta usage (mean V beta CD4+ R2 = 0.869 and CD8+ R2 = 0.833) and to a lesser extent V alpha usage (mean V alpha CD4+ R2 = 0.621 and CD8+ R2 = 0.627); whereas the patterns between unrelated individuals show more variability. This study has also demonstrated that the V alpha and V beta genes are not randomly used within the CD4+ and CD8+ subsets. We observed significant preferential skewing of several V alpha or V beta gene families to either the CD4+ or CD8+ subset in the majority of individuals analyzed (p-value range = 0.0476 to < 0.001). In particular, V alpha 11, 17, 22, and V beta 3, 9, 12, 18 were skewed to the CD4+ subset; whereas V alpha 2, 6, 12, 15, 20 and V beta 7, 14, 17 were skewed to the CD8+ subset. Furthermore, a number of the V genes showed patterns of skewing consistent only within a pair of twins. In three pairs of twins, V beta 2 was skewed to the CD4+ subset, whereas the fourth pair used almost equal frequencies of V beta 2 in both subsets. This observation was made for the V beta 2, 4, 5, 6, 8, 19 and V alpha 7, 16, 18, 21 families. Finally, the ratio of the relative V gene usage frequency that could be observed within an individual was conserved within the sets of twins; for instance, the relative amount of V beta 2 to that of V beta 3 was higher in both individuals of one set of twins, whereas it was lower in all of the other three sets. Together these observations suggest that the predominant influence shaping the TCR repertoire is genetically predetermined, of which, HLA-predicted selection mechanisms exerted during thymic maturation might be contributing factors.     

IL-16 activates the SAPK signaling pathway in CD4+ macrophages

IL-16 has been reported as a modulator of T cell activation and was shown to function as chemoattractant factor. The chemotactic activity of IL-16 depends on the expression of CD4 on the surface of target cells, but the intracellular signaling pathways are only now being deciphered. This report describes IL-16 as an additional activator of the stress-activated protein kinase (SAPK) pathway in CD4+ macrophages. Treatment of these cells with recombinant expressed IL-16 leads to the phosphorylation of SEK-1, resulting in activation of the SAPKs p46 and p54. IL-16 stimulation also leads to the phosphorylation of c-Jun and p38 MAPK (mitogen-activated protein kinase), without inducing MAPK-family members ERK-1 and ERK-2. Interestingly, the IL-16-mediated activation of SAPKs and p38 MAPK in macrophages alone induces no detectable apoptotic cell death. These observations suggest specific regulatory functions of IL-16 distinct from the proinflammatory cytokines TNF-alpha and IL-1beta.     

Processing and release of IL-16 from CD4+ but not CD8+ T cells is activation dependent

IL-16 is synthesized as a precursor molecule of 68 kDa (pro-IL-16) that is processed by caspase-3, a member of the IL-1 converting enzyme (ICE) family. This cleavage results in a 13-kDa carboxy terminal peptide, which constitutes the bioactive secreted form of IL-16. We have previously reported constitutive IL-16 mRNA expression and pro-IL-16 protein in CD4+ and CD8+ T cells. Although bioactive IL-16 protein is present in unstimulated CD8+ T cells, there is no bioactive IL-16 present in CD4+ T cells. Along these lines, unstimulated CD8+ T cells contain active caspase-3. In the current studies we investigated the regulation of IL-16 protein and mRNA expression in CD4+ T cells and determined the kinetics of secretion following stimulation of the TCR. CD4+ T cells release IL-16 protein following antigenic stimulation, and this release is accelerated in time by costimulation via CD28. However, CD3/CD28 costimulation did not alter IL-16 mRNA appearance or stability in either CD4+ or CD8+ T cells. The secretion of bioactive IL-16 from CD4+ T cells correlated with the appearance of cleavage of pro-caspase-3 into its 20-kDa active form. Thus, resting CD8+ T cells contain active caspase-3 that is capable of cleaving pro-IL-16, whereas CD4+ T cells require activation for the appearance of active caspase-3. The mechanism of release or secretion of bioactive IL-16 is currently unknown, but does not correlate with cellular apoptosis.     

Maternal instinct in women with complicated pregnancy

Using an Ussing chamber, both the posterior epithelial membrane and cultured epithelial cell monolayers from canine trachea were used for measurements of potential difference (PD) and short circuit current (SCC). Conductance (G) was calculated as the ratio SCC/PD. Adenosine (10(-5) to 10(-3) M) failed to produce any significant increases in PD and SCC. ATP (10(-6) to 10(-4) M) produced a significant transient increase in SCC in a dose-dependent fashion, reaching a peak value within 3 min after stimulation. Isoproterenol (ISOP) at 10(-8) M itself did not significantly alter the SCC value. In both the epithelial membrane and cultured epithelial cells treated with amiloride, however, pretreatment with 10(-8) M ISOP significantly augmented the ATP-induced SCC rise, whereas G did not significantly change. These findings indicate that beta-adrenergic stimulation augments Cl- secretion induced by P2-receptor stimulation in airway epithelial cells.