Beta-adrenergic receptor desensitization of wild-type but not cyc lymphoma cells unmasked by submillimolar Mg2+

Treatment with low physiological concentrations of epinephrine (5-50 nM) rapidly desensitizes beta-adrenergic stimulation of cAMP formation in S49 wild-type (WT) lymphoma cells. Previous attempts to detect this early phase of desensitization in cell-free assays of adenylate cyclase (EC 4.6.1.1) after intact cell treatment were unsuccessful. We have now found that reducing the Mg2+ concentrations in the adenylate cyclase assays to less than 1.0 mM unmasked this rapid phase of desensitization of the WT cells, and that high Mg2+ concentrations (5-10 mM) largely obscured the desensitization. Submillimolar Mg2+ conditions also revealed a two- to threefold decrease in the affinity of epinephrine binding to the beta-adrenergic receptor after desensitization with 20 nM epinephrine. Detection of 4 beta-phorbol 12-myristate 13-acetate (PMA) desensitization of the WT beta-adrenergic receptor was also dependent on low Mg2+ as measured either by the decrease in epinephrine stimulation of adenylate cyclase or by the reduction in the affinity of epinephrine binding. Unexpectedly, when cyc- cells were pretreated with 50 nM epinephrine, the beta-adrenergic stimulation of reconstituted adenylate cyclase was not desensitized. The characteristics of the Mg2+ effect on epinephrine- and PMA-induced desensitizations suggest a similar mechanism of action with the most likely events being phosphorylations of the beta-adrenergic receptors. Our data indicate that cAMP-dependent protein kinase (EC 2.7.1.37) may play a role in the desensitization caused by low epinephrine concentrations inasmuch as this phase of desensitization did not occur in the cyc-. For the PMA-induced desensitization, the phosphorylation may be mediated by protein kinase C (EC 2.7.1.37).

Sodium current in single cells from bullfrog atrium: voltage dependence and ion transfer properties

1. Whole-cell and patch-clamp techniques (Hamill, Marty, Neher, Sakmann & Sigworth, 1981) have been used to make quantitative measurements of the transient inward sodium current (INa) in single cells from bullfrog atrium. This preparation is particularly suitable for the study of INa: (i) the current density is relatively low, (ii) the cells lack a transverse tubule system, (iii) isolated myocytes can be maintained at reduced temperatures (approximately 8-12 degrees C); therefore kinetics can be studied quantitatively. 2. INa was pharmacologically and kinetically isolated from other transmembrane currents by blocking ICa with CdCl2 (0.2-0.5 mM) or LaCl3 (5 x 10(-6) M), and by using only relatively short voltage-clamp depolarizations which did not activate IK (the delayed rectifier). 3. The voltage dependence of INa in bullfrog atrium is similar to that in amphibian node of Ranvier or fast skeletal muscle. The threshold for activation is approximately -50 mV. The peak of the INa vs. membrane potential relation is near -5 to -10 mV. The reversal potential in 'normal' (115 mM-Na+) Ringer solution is +59.0 mV (S.D. +/- 3.4, n = 10). Reduction of external Na+ concentration to one-third of normal resulted in an approximately -27 mV shift of the reversal potential, close to that expected for a highly Na+-selective conductance. 4. Steady-state inactivation of INa (h infinity), measured with a conventional two-pulse voltage-clamp protocol, spanned the membrane potential range from -90 to -50 mV. The potential dependence of h infinity was well described by a single Boltzmann function with half-inactivation at -71 mV and maximum slope of 6.0 mV. 5. Steady-state activation of INa (m infinity) was determined from fits of INa records to a Hodgkin-Huxley model. The potential dependence of m infinity was fitted to a Boltzmann function with half-activation at -33 mV and maximum slope of 9.5 mV. Thus at temperatures around 10 degrees C there was very little overlap of the m infinity and h infinity curves, and only very small steady-state 'window' currents are predicted. 6. The activation time constant, tau m, had a 'bell-shaped' dependence on membrane potential. The peak value of tau m was about 4.2 ms, at a membrane potential of -35 mV (9 degrees C). 7. The time course of inactivation of INa was consistently better described by the sum of two exponentials than by one exponential.(ABSTRACT TRUNCATED AT 400 WORDS)

New causes of pneumonia, meningitis, and disseminated infections associated with immersion

Immersion in water increases the risk of infection by certain microorganisms, including bacteria, fungi, and parasites. Physicians should be aware of this relationship because many of these infections are not normally encountered except in association with water exposure. The morbidity and mortality associated with these infections may be substantial. Clinical features of pneumonia, disseminated infection, and central nervous system infections are detailed.

The protein kinase C inhibitor H-7, inhibits antigen and IL-2-induced proliferation of murine T cell lines

Activation of protein kinase C has been shown to be involved in the activation pathway of many cell types. Recently, a number of investigations have suggested that protein kinase C plays an essential role in T lymphocyte activation. The recent synthesis of the protein kinase inhibitors, H-7 and HA1004, have now made possible a new approach for testing the relevance of protein kinase C in T cell activation and proliferation. We now report that the antigen-induced and interleukin-2-induced proliferation of murine T cell lines can be consistently inhibited by the protein kinase C inhibitor, H-7. HA1004, a somewhat more potent inhibitor of cyclic nucleotide-dependent protein kinases, but a significantly weaker inhibitor of protein kinase C than H-7, demonstrated no consistent inhibition of these T cell responses. These results represent a further demonstration that protein kinase C plays an essential role in the activation of T cells.

Complement dependent in vitro neutralization of Chlamydia trachomatis by a subspecies-specific monoclonal antibody

Three murine monoclonal antibodies which combined specifically with Chlamydia trachomatis strain HAR-13 (Serotype A) were characterized. All antibodies cross-reacted with subspecies-specific epitopes in previously undescribed patterns. One of the antibodies showed a complement-dependent partial neutralization of strain HAR-13 in vitro, whereas the remaining two antibodies did not neutralize under any experimental conditions tested. The significance of subspecies-specific antibodies in neutralizing chlamydial infectivity in vivo remains to be determined.

Activity of ciprofloxacin against Mycobacteria in vitro: comparison of BACTEC and macrobroth dilution methods

Various clinical isolates of mycobacteria were tested for susceptibility to ciprofloxacin by a standard macrobroth dilution test and the radiometric BACTEC method. Agreement between the two test systems was species dependent: Mycobacterium tuberculosis (80%), M. kansasii with M. scrofulaceum (30%), M. avium-intracellulare (20%), and 0% for the rapidly growing mycobacteria. Most mycobacterial strains other than M. tuberculosis were susceptible to the breakpoint ciprofloxacin concentration of 2 mg/l as determined by BACTEC MICs, whereas none were susceptible by macrobroth testing. Seven of nine M. tuberculosis isolates were susceptible by either method. Ciprofloxacin merits further study as a potential antimycobacterial agent.

Allogeneic fibroblasts and endothelial cells support mitogen but not antigen responses of tetanus-responsive T-cell lines

Recent studies suggest a role for endothelial cells (EC) and fibroblasts (FB) in performing certain accessory functions of monocytes in immune responses. We examined the ability of allogeneic adherent cells (AC), umbilical vein EC, and foreskin FB to support antigen and mitogen responses of tetanus toxoid-responsive human T-cell lines (TCTet). Syngeneic AC supported antigen and mitogen (phytohemagglutinin and pokeweed mitogen, PHA and PWM) responses of TCTet. Allogeneic AC, EC, and FB supported mitogen but not antigen responses of TCTet, in a dose-dependent manner. PHA-activated mononuclear cell supernates or EC or FB supernates could not replace accessory cells in mitogen responses. We provide further evidence that EC and FB can function as fully competent accessory cells, a function that may be of significance in in vivo initiation of immune responses.

T cell lines derived from the spinal cords of mice with experimental allergic encephalomyelitis are self reactive

Experimental allergic encephalomyelitis (EAE) is an animal model of T cell-mediated, central nervous system neuropathology that may be a relevant animal model for multiple sclerosis. EAE is usually induced by sensitization of animals with a xenogeneic myelin basic protein (MBP). Recently, MBP-reactive T cell lines and clones derived from lymphoid tissue of animals with EAE have proved very useful in elucidating certain aspects of the pathogenesis in EAE. However, questions relating to how T cells actually mediate the pathologic changes seen in EAE remain unresolved. We now report for the first time the derivation of long-term, interleukin 2-dependent T cell lines and sublines from a site of pathology in murine EAE--the spinal cord. All of the spinal cord-derived T cell lines and sublines were found to be "autoreactive" in that they responded to self (murine) MBP as well as to the xenogeneic immunogen, porcine MBP. The ability to derive T cell lines and sublines from the spinal cords of mice with EAE should now aid in the elucidation of pathogenetic mechanisms in EAE by allowing for a characterization of those T cells found at the site of pathology.

T cell lines derived from the spinal cords of mice with experimental allergic encephalomyelitis are self reactive

Experimental allergic encephalomyelitis (EAE) is an animal model of T cell-mediated, central nervous system neuropathology that may be a relevant animal model for multiple sclerosis. EAE is usually induced by sensitization of animals with a xenogeneic myelin basic protein (MBP). Recently, MBP-reactive T cell lines and clones derived from lymphoid tissue of animals with EAE have proved very useful in elucidating certain aspects of the pathogenesis in EAE. However, questions relating to how T cells actually mediate the pathologic changes seen in EAE remain unresolved. We now report for the first time the derivation of long-term, interleukin 2-dependent T cell lines and sublines from a site of pathology in murine EAE--the spinal cord. All of the spinal cord-derived T cell lines and sublines were found to be "autoreactive" in that they responded to self (murine) MBP as well as to the xenogeneic immunogen, porcine MBP. The ability to derive T cell lines and sublines from the spinal cords of mice with EAE should now aid in the elucidation of pathogenetic mechanisms in EAE by allowing for a characterization of those T cells found at the site of pathology.

Comparison of steady-state electrophysiological properties of isolated cells from bullfrog atrium and sinus venosus

Single electrode whole cell voltage-clamp experiments and frequency domain analyses have been used to study and compare the K+ currents in enzymatically dispersed single cells from the atrium and the sinus venosus (pacemaker region) of the bullfrog heart. Admittance measurements made near the "resting' or zero-current potential yield data from which the equivalent circuit of each cell type may be obtained. Data from both atrial and pacemaker cells are well-fitted by a model consisting only of parallel resistance-capacitative elements, as predicted from their micro-anatomy. Neither of these amphibian cardiac cells contain a transverse tubule system (TT) and both have very little sarcoplasmic reticulum (SR). These results complement and extend two earlier investigations: (i) Moore, Schmid and Isenberg (J. Membrane Biol. 81:29-40, 1984) have reported that in guinea pig ventricle cells (which do contain an internal membrane system consisting of transverse tubules and a substantial SR) the SR may be electrically coupled to the sarcolemma; (ii) Shibata and Giles (Biophys. J. 45:136a, 1984) have shown that although bullfrog atrial cells have an inwardly rectifying background K+ current, IK1, pacemaker cells from the immediately adjacent sinus venosus do not. Data from admittance measurements also provide evidence that a TTX-insensitive inward Ca2+ current is activated in the pacemaker range of potentials.

Homologous desensitization of beta-adrenergic receptors in lymphoma cells is not altered by the inactivation of Ni (Gi), the inhibitory guanine nucleotide regulatory protein

We had previously demonstrated that the cyc- mutant of S49 wild-type lymphoma cells both desensitizes and undergoes a sequestration-internalization of the beta-receptor in response to short-term treatment with adrenaline. The cyc- mutant of S49 wild-type lymphoma cells lacks the alpha s subunit of the stimulatory coupling protein Ns, but has fully functional Ni, the inhibitory component of the regulatory complex. This suggested that functional Ns was not required for desensitization. To examine the role of Ni in desensitization, both S49 wild-type and cyc- cells were treated with islet-activating protein under conditions that led to over 85% attenuation of Ni function in S49 wild-type cells and approx. 50% attenuation of Ni function in cyc- cells. This treatment had no effect on the adrenaline-induced desensitization of adenylate cyclase or the sequestration event measured by the apparent movement of beta-adrenergic receptors to a light-vesicle fraction. Further, the desensitization event, which occurs before the sequestration event, observable only in intact cells, was also not altered by islet-activating-protein pretreatment of S49 wild-type cells. The data suggest that a functional Ni is not required for desensitization in the S49 lymphoma cells.

Cell-mediated immunity in rheumatic disease

Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis are the three most common systemic rheumatic diseases in which disordered immune function is thought to play a pathogenetic role. Each disease has different and characteristic abnormalities of the cellular immune system. In rheumatoid arthritis the identified abnormalities of immunoregulation are largely limited to specific antigens: Epstein-Barr virus and collagen. Systemic lupus erythematosus is characterized by exuberant B-cell activity with exaggerated humoral response, a diversity of autoantibodies, non-antigen-specific loss of suppressor cell function, and general suppression of cell-mediated immunity. In systemic sclerosis systemic defects of cellular and humoral immune function are mild, but the release of lymphokines and monokines at sites of inflammatory lesions is thought to be important in the pathogenesis of the disease. Similar immune cell-connetive tissue cell interactions are probably important in the propagation of rheumatoid synovitis. Thus, despite the many shared clinical and serologic features of these diseases as well as the presence of many patients who have clinically overlapping features of more than one of these entities, the immune defects and the immunopathogenesis of these disorders appear to be distinct.

A1 and A2 adenosine receptors regulate adenylate cyclase in cultured human lung fibroblasts

Adenosine stimulates and inhibits adenylate cyclase activity and cAMP levels in WI-38 and VA13 fibroblasts. The inhibitory effects appear to be mediated by both A1 receptors and the P-site. Results supporting these conclusions are as follows: Adenosine by itself increased cAMP accumulation in these cells. PGE1-stimulated cAMP accumulation was inhibited by adenosine in a concentration-dependent fashion. IAP treatment blocked adenosine inhibition of cAMP accumulation and adenylate cyclase activity and enhanced adenosine stimulation of cAMP accumulation in VA13 cells. Theophylline and MIX attenuated adenosine inhibition of cAMP accumulation. Adenosine analogs with substitutions in the purine ring inhibited PGE1-stimulated cAMP accumulation and adenylate cyclase activity. PGE1-stimulated cAMP accumulation was inhibited by the P-site agonist 2'5'-dideoxyadenosine, but this inhibition was not attenuated by MIX or IAP treatment. These data support the idea that adenosine may inhibit cAMP accumulation in VA13 or WI-38 cells by acting at an A1 receptor of the P-site. The decrease in cAMP accumulation mediated by the A1 receptor appeared to be due at least in part to an Ni-mediated inhibition of adenylate cyclase.

Cervical chlamydial infections: diagnostic accuracy of the Papanicolaou smear

To assess the reliability and accuracy of the Papanicolaou smear for the detection of cervical Chlamydia trachomatis infections, we obtained chlamydial cultures and cervical smears from 252 patients attending a gynecologic service during an eight-month time period. In 12 of these patients (4.8%), the cervical culture was positive for chlamydiae but the cytologic smear was negative for chlamydial inclusions. Five smears (2.2%) were cytologically positive for chlamydiae but were negative by culture. In none of the patients were both culture and smear positive for chlamydiae. In our experience the smear was a completely unreliable test for the diagnosis of cervical C trachomatis infections. The cytologic smear should not replace culture for the detection of chlamydial infections.

Phosphatidate and monooleylphosphatidate inhibition of fibroblast adenylate cyclase is mediated by the inhibitory coupling protein, Ni

It has previously been shown that monooleylphosphatidate (MOPA) and phosphatidate inhibit cAMP accumulation in VA13 and WI-38 fibroblasts. In this study we investigated whether this inhibition might be due to a decrease in adenylate cyclase activity. Our results showed that both MOPA and phosphatidate inhibit prostaglandin E1-stimulated adenylate cyclase in WI-38 membranes in a concentration-dependent manner with half-maximal inhibitions at 0.1 and 0.5 microM, respectively, and maximal inhibitions of 35-55%. A 5 microM concentration of structurally similar lipids caused no significant inhibition. The inhibitory effects of MOPA and phosphatidate on adenylate cyclase were GTP dependent, greater at low concentrations of Mg2+, eliminated following treatment of cells with islet-activating protein, nonadditive with carbachol, and noncompetitive with prostaglandin E1. Collectively these data suggested that MOPA and phosphatidate inhibitions of cAMP accumulation were due at least in part to an Ni-mediated inhibition of adenylate cyclase. Furthermore, the inhibitions showed the same characteristics normally associated with hormonal inhibition of this enzyme.

Compartmentalized immune responses: antigen-specificity of cerebrospinal fluid T-cell lines maintained in the absence of antigen

The generation of long-term interleukin 2-dependent T-cell lines from anatomically compartmentalized sites of pathology offers a unique approach to the investigation of certain autoimmune diseases. However, it is generally believed that antigen-specific T-cell lines and clones lose antigen reactivity and specificity when propagated in the absence of antigen. Therefore, the optimal application of this approach to such diseases in which the pathogenetic antigens are unknown may be difficult. In approaching this problem, we have recently demonstrated that a proportion of antigen-specific T-cell lines derived from the peripheral circulation can maintain antigen specificity if propagated with antigen-presenting cells alone or with antigen-presenting cells together with OKT3 antibody, but in either case in the absence of antigen. In this report we describe the use of this approach to maintain the antigen specificity of T cells obtained from an anatomically compartmentalized site of pathology--the cerebrospinal fluid from a patient with tuberculous meningitis. We report here that a proportion of the T-cell lines generated from such cerebrospinal fluid lymphocytes can be maintained as antigen specific in the absence of antigen if propagated with either antigen-presenting cells alone or with antigen-presenting cells and OKT3 antibody. The approach illustrated in this report should now find broad applicability in the investigation of a number of autoimmune disease.

Isolation of Serratia plymuthica from a human burn site

The saprophytic bacterium Serratia plymuthica was recovered from a facial wound (burn) site of a pediatric patient. The clinical significance of the organism was undetermined due to its apparent eradication from this location by therapy with topical 1% silver sulfadiazine. Seeding of the burn with S. plymuthica may have occurred from contaminated moisture sometimes found on and around steam radiators.

Maintenance of antigen specificity by human interleukin-2-dependent T cell lines. Use of antigen-presenting cells and OKT3 antibody in the absence of antigen

The in vitro growth of T cells obtained from localized anatomic sites of pathology may offer a new approach to the investigation of certain human autoimmune diseases. However, if interleukin-2-dependent T cell cloning is to be useful in helping to elucidate putative pathogenetic antigens in these diseases, the expansion of the small number of T cells obtainable from localized anatomic sites of pathology will often have to be accomplished in the absence of these, as yet undetermined, antigens. At present, it is a generally held belief that antigen-responsive, interleukin-2-dependent T cell lines and clones will lose antigen responsiveness if propagated in the absence of specific antigen. Thus, the use of T cell cloning might be viewed as being of limited usefulness in the investigation of certain human autoimmune diseases. In this report we demonstrate that, when propagated in the absence of antigen, human tetanus toxoid-specific, interleukin-2-dependent T cell lines will indeed lose antigen reactivity. However, if propagated in the absence of antigen but in the presence of antigen-presenting cells, the tetanus toxoid reactivity of a subset of such lines can be maintained. Moreover, the propagation with OKT3 antibody, in addition to antigen-presenting cells, may be even more effective in maintaining antigen reactivity. These results may suggest a new approach to the use of T cell cloning technology in the investigation of certain autoimmune diseases.

Value of blood agar for primary plating and clinical implication of simultaneous isolation of Aeromonas hydrophila and Aeromonas caviae from a patient with gastroenteritis

The simultaneous recovery of Aeromonas hydrophila and Aeromonas caviae from the stool of a 49-year-old woman with watery diarrhea was facilitated through the use of a blood agar medium which detected the hemolytic capability of A. hydrophila. In vitro phenotypic tests support the conclusion that only the A. hydrophila isolate was clinically significant.

Generation of long-term T-cell lines from synovial fluid

Investigations of human autoimmune diseases have largely involved study of circulating T cells. The development of T-cell cloning technology has made possible the study of the small numbers of T cells found at sites of pathological involvement in autoimmune diseases. In this initial communication, the feasibility of in vitro propagation of synovial fluid T cells from patients with arthritis is demonstrated. The generation of long-term, phenotypic helper/inducer, as well as phenotypic suppressor/cytotoxic, interleukin 2-dependent synovial fluid T-cell lines from patients with arthritis is reported. The ability to generate such synovial fluid T-cell lines should now allow for new investigative approaches to human autoimmune arthritic diseases.

Biotyping and exoenzyme profiling as an aid in the differentiation of human from bovine group G streptococci

Group G streptococci were isolated from throat and extrapharyngeal cultures from 75 patients during an 18-month period. Of 29 throat isolates, 18 were recovered from patients with pharyngitis, 8 were of unknown significance, and 3 were of questionable etiology. Clinical significance could be ascribed to 13 of 46 extrapharyngeal isolates recovered from wound, urinary tract, blood, and conjunctival cultures. Extrapharyngeal isolates recovered from stool, sputum, and vaginal cultures were considered nonsignificant. A total of 96 group G streptococcal strains (including 21 human and 14 bovine strains from outside sources) were tested for exoenzyme production and subjected to a large battery of biochemical tests. Bovine and human isolates could be distinguished on the basis of trehalose fermentation, litmus milk reduction, and production of beta-D-glucuronidase, hyaluronidase, and fibrinolysin. Eight distinct biotypes could be discerned on the basis of fermentation of trehalose, raffinose, and lactose and esculin hydrolysis. All isolates that fermented raffinose were associated with infection. These results support the concept of two distinctly different epidemiological reservoirs of group G streptococci in humans and bovines.

Long-term T-cell lines from the tears of patients with vernal conjunctivitis

Previous studies of the tears and conjunctival tissue of vernal conjunctivitis (VC) have suggested that cellular immune mechanisms may be important in the inflammatory process of this ocular disease. However, little information is available in support of a cell-mediated immune mechanism because of the difficulty of tissue access and the small numbers of mononuclear cells in the tear secretions. Tear secretions of VC patients contain few lymphocytes (estimated 10(3) per 300 microliters of tears). Tear lymphocytes from 5 of 7 VC patients were propagated in culture in the presence of interleukin 2. In 2 months of culture the tear lymphocytes were expanded to 5 x 10(6)-10(7) cells. Phenotyping studies with monoclonal antibodies showed that all cell lines exhibited T-cell markers. In 2 of 3 tear specimens which were initially cultured in the presence of the putative specific antigen, i.e. rye grass or ragweed antigen E, the OKT4 helper/inducer phenotype predominated while the cell lines without antigen exhibited mostly the OKT8 phenotypes. These studies demonstrated the feasibility of generating long-term IL-2 dependent T-cell lines from the tear secretions of patients with VC which will enable the study of localized cellular immune processes in external ocular disease.

Phenotypic factors correlated with the absence of virulence among gentamicin-resistant Pseudomonas aeruginosa strains

Previous reports have suggested that clinical strains of gentamicin-resistant Pseudomonas aeruginosa (GRPA) generally produce only superficial infections (wounds, urinary tract infections) in contrast to their more invasive gentamicin-susceptible counterparts (GSPA). In view of this finding, a comparative study of a number of phenotypic properties of 20 GRPA and GSPA strains (10 isolates) was assessed to determine how closely related these two populations are and how their phenotypic properties might reflect virulence. GRPA isolates were found to be more adherent to buccal cells than their susceptible counterparts (P = 0.0001). Motility, however, was generally restricted in the GRPA population when compared with GSPA isolates (P = 0.02), although on the basis of zone diameters, some strains overlapped into the other group. Enzymatically, GSPA isolates produced significantly more lipase activity against C-14 lipids than GRPA strains (P = 0.04). No differences were recorded between the two populations in dye sensitivity or in their ability to grow on minimal media at 37 and 42 degrees C. Only 35% of the GRPA isolates agglutinated in 1 of the 17 monospecific antisera reactive for P. aeruginosa. The results of this study suggest that in vivo-generated GRPA strains possess phenotypic properties intermediate between those described for in vitro-derived GRPA isolates and their progenitor GSPA strains. The increased adherence of clinical GRPA isolates to buccal cells may explain their predilection to produce wound and urinary tract infections, whereas their lack of systemic dissemination may be partially due to decreased motility and to reduced lipase production.

Generation of phenotypic helper/inducer and suppressor/cytotoxic T-cell lines from cerebrospinal fluid in multiple sclerosis

The investigation of cell-mediated events in man has been largely limited to the study of the cells in the peripheral circulation. The study of T cells from localized anatomic compartments has been difficult due to the small numbers of cells usually obtainable from these sites. Investigation of such compartmentalized responses theoretically may yield information relating to both normal immunoregulation and autoimmune diseases--information that may not be obtainable through the investigation of the circulating cellular immune system. Utilizing cerebrospinal fluid (CSF) lymphocytes from patients with multiple sclerosis as a model of compartmentalized immunologically relevant cells, the technology for the generation of long-term T-cell lines from compartments both in continuous culture and after cryopreservation and that consist of both helper/inducer and suppressor/cytotoxic phenotypes have been generated. The 10(4) to 10(5) CSF cells obtained initially from individual patients have often been expanded into greater than 10(8) total cells within 4 months. The ability to generate large, stable, cryopreservable helper and suppressor/cytotoxic T-cell lines from limited access compartments will allow for new investigative approaches into both normal immunoregulation and autoimmune diseases in man.

Morphological aberrations of nutritionally deficient streptococci: association with pyridoxal (vitamin B6) concentration and potential role in antibiotic resistance

A strain of a nutritionally deficient streptococcus was shown to undergo morphological aberrations according to pyridoxal concentrations in the growth medium. Filamentous rod-shaped cells, observed by electron microscopy, predominated in the presence of decreasing concentrations. Multiple invaginations in the outer cell wall suggested inhibition of binary fission. Penicillin antimicrobial studies performed in the presence of similar pyridoxal concentrations indicated a relationship between filamentous forms and penicillin susceptibility.

Photoaffinity labeling of the beta-adrenergic receptor from cultured lymphoma cells with [125I]iodoazidobenzylpindolol: loss of the label with desensitization

The beta-adrenergic antagonist [125I]iodoazidobenzylpindolol ( [125I]IABP) specifically photolabeled two polypeptides in membrane preparations from wild-type (WT) and coupling protein-deficient cyc- cultured lymphoma cells. The molecular weights of the two polypeptides determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis were 65,000 and 55,000. They were labeled in a ratio of approximately 1:1. Pretreatment of intact WT or cyc- cells with 1.0 microM epinephrine for 15 min (desensitization) resulted in a greater loss of the 55,000 Mr polypeptide (40-60%) relative to the 65,000 Mr peptide (10-30% loss). An 18- to 24-hr pretreatment of WT cells with terbutaline (down-regulation) led to a greater than 90% reduction of the photolabeling of both polypeptides, whereas a similar pretreatment of cyc- cells resulted in no further loss of labeled receptor than that observed after only a 15-min pretreatment with epinephrine. There was no indication of a change in the electrophoretic mobility of the [125I]IABP-labeled receptors after either short- or long-term agonist pretreatment. These data provide direct evidence for heterogeneity of the beta-adrenergic receptor in lymphoma cells. The differential loss of the [125I]IABP labeling in the two polypeptides suggests a functional heterogeneity as well.

Ultrastructural analysis of the effects of erythromycin on the morphology and developmental cycle of Chlamydia trachomatis HAR-13

The effect of erythromycin (10 micrograms/ml) on the morphology and developmental cycle of Chlamydia trachomatis HAR-13 was examined by electron microscopy. When the antibiotic was added later than 24 h post infection, the HAR-13 morphology or developmental cycle was not altered. Addition at 18 or 24 h post infection inhibited glycogen production, blocked the transformation of the reticulate body to elementary body, and produced ghost bodies and reticulate bodies twice the diameter of untreated reticulate bodies. When erythromycin was added within 12 h post infection, the conversion of the elementary body to reticulate body was inhibited. Erythromycin (10 micrograms/ml) was bactericidal to strain HAR-13 throughout the developmental cycle.

Localization of distinct surface antigens on Chlamydia trachomatis HAR-13 by immune electron microscopy with monoclonal antibodies

Monoclonal antibodies were produced against the HAR-13 strain (A) of Chlamydia trachomatis. By an indirect immunofluorescence technique, three clones (1-7, 2-8, 9F) were found to produce antibody that reacted only with serotype A strains. Clone 3-5 produced antibody that cross-reacted with serotypes A, C, H, I, and J. Using an indirect immunoferritin technique, we examined the binding of these antibodies to strain HAR-13 by electron microscopy. Antibodies from all four clones were shown to bind to the outer membrane surface of both reticulate and elementary bodies. Two distinct binding patterns were demonstrated. Antibodies from clones 1-7 and 9F bound to the outer membrane surface in a homogeneous pattern, whereas antibodies 2-8 and 3-5 bound to the outer membrane surface in an irregular, patchy distribution. There was a direct correlation between the distribution of antigen on the outer membrane surface and neutralization of C. trachomatis HAR-13 infectivity in vitro. Neutralization of HAR-13 infectivity by antibodies 1-7 and 9F was complement dependent, whereas antibodies 2-8 and 3-5 did not neutralize under any conditions.

Ultrastructural effect of penicillin and cycloheximide on Chlamydia trachomatis strain HAR-13

The effect of cycloheximide and penicillin on the ultrastructural morphology of C. trachomatis strain HAR-13 was examined by electron microscopy. HAR-13 infected McCoy cells were either treated with cycloheximide (1 microgram/ml) or cycloheximide (1 microgram/ml) plus penicillin G (100 U/ml). The studies revealed that cycloheximide alone induced no morphological alterations into the ultrastructure of HAR-13. Both HAR-13 developmental forms, the elementary body and reticulate body, were present inside the treated McCoy cells. The elementary bodies contained the central dense nucleoid and were about 0.3 microns in diameter, while the reticulate bodies were of typical gram negative bacterial morphology and were from 0.5-1.0 microns in diameter. Cycloheximide in combined treatment with pencillin produced giant, swollen reticulate bodies that were 2-4 microns in diameter and in some cases vacuolated. Elementary bodies were noticeably absent. These results indicate that cycloheximide does not alter the morphology of HAR-13. This system is a useful model for studying the ultrastructural morphology of C. trachomatis strain HAR-13.

Differences in the forskolin activation of adenylate cyclases in wild-type and variant lymphoma cells

The ability of the diterpene forskolin to stimulate cyclic AMP accumulation in intact cell and membrane preparations of wild-type S49 lymphoma cells (WT) and a number of variants has been confirmed. Additionally, a number of salient new findings have emerged: (a) A time delay in forskolin stimulation of cyclic AMP accumulation and adenylate cyclase (t 1/2 approximately equal to 1.5 min) occurred in all hormone-sensitive WT and variant cell and membrane preparations tested. (b) The time delay was missing in the adenylate cyclase-deficient variant (cyc-) of the S49 lymphoma cell, which also lacks functional adenylate cyclase-coupling proteins. (c) The simultaneous addition of epinephrine and forskolin to WT cells or to membrane preparations eliminated the time delay. (d) Forskolin stimulation of intact WT cells did not appear to desensitize adenylate cyclase. (e) The activation of WT adenylate cyclase by forskolin was biphasic with respect to concentration, with both high- and low-affinity components being apparent. In cyc-, only the low-affinity component was detected.

Specific muscarinic-cholinergic desensitization in the neuroblastoma-glioma hybrid NG108-15

The cholinergic agonist carbachol, epinephrine, and the opiate morphine all inhibit prostaglandin E1 (PGE1)-stimulated adenylate cyclase in homogenates from the neuroblastoma-glioma hybrid NG108-15. Pretreatment of the hybrid with 100 microM carbachol resulted in the rapid loss (desensitization) of the carbachol inhibition of adenylate cyclase (t1/2 less than 3 min). The desensitization of the carbachol inhibition was blocked by 0.1 microM atropine. Pretreatment with carbachol (1-24 h) did not significantly affect the inhibition of adenylate cyclase by either epinephrine or morphine, nor did it alter the PGE1-stimulated activity, that is, no supersensitization was observed. Cholate extracts of the particulate fraction from either carbachol-desensitized or of control NG108-15 were able to reconstitute adenylate cyclase activities of the coupling proteins (G/F)-deficient cyc- lymphoma cell membranes with equal efficacy. These results suggested that the coupling proteins of the adenylate cyclase were not altered by the carbachol pretreatment and that desensitization occurs at the receptor or at a receptor-associated level. However, the possibility remained that specific domains of the G/F, which interact only with muscarinic receptors, were altered.

Block of locust muscle glutamate receptors by delta-philanthotoxin occurs after receptor activations

One component (delta-philanthotoxin (delta-PTX) of the venom from the wasp Philanthus triangulum blocks transmission postsynaptically at excitatory synapses on locust muscle. delta-PTX depresses both the iontophoretic glutamate potential and the excitatory junctional current (e.j.c.) in a glutamate receptor activation-dependent manner. The rate of recovery from the effects of the toxin is reduced following either prolonged application of L-glutamate or repetitive iontophoretic application of this amino acid or high frequency neural stimulation of the muscle in the presence of delta-PTX. The decay phase of the e.j.c. is shortened by delta-PTX. The effects of delta-PTX on the e.j.c. are not voltage dependent. The open-close kinetics of glutamate channels in extrajunctional muscle membrane are modified by delta-PTX as shown by patch clamp analysis. The mean life time of the glutamate channel is reduced, whilst the mean interval between single opening events is increased with the events often occurring in bursts. These data are consistent with glutamate channel blocking by this toxin. It is proposed that the toxin blocks open channels gated by both junctional and extrajunctional glutamate receptors on locust muscle. It is further proposed that delta-PTX enters a compartment of the muscle through the glutamate open channels and that it can also block the open channels from this site.

Generation of T cell colonies from responder strain 2 guinea pigs that recognize the copolymer L-glutamic acid, L-lysine in association with nonresponder strain 13 Ia antigens

T cells from nonimmune responder strain 2 guinea pigs were primed in vitro to the copolymer GL in association with allogeneic, nonresponder strain 13 PEC. T cells that recognized GL in association with strain 13 Ia were separated from alloreactive T cells by cloning the population in soft agar following the priming in liquid culture. The existence of T cells of responder origin that recognize antigen in association with nonresponder macrophages is most consistent with clonal deletion models of Ir gene function.