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Passive transfer of immunity of Mycobacterium avium in susceptible and resistant strains of mice.

Naturally susceptible mice (C57BL/6) infected with M. avium (strain Weybridge) developed a population of splenic T cells which, on transfer to syngeneic recipient mice, conferred significant protection against a subsequent challenge inoculum of M. avium. Similar T cells from naturally resistant mice (A/J) did not protect syngeneic recipient mice. Growth of M. avium in donor mice only occurred in the C57BL/6 strain. Replication of M. avium in donor mice was necessary for the development of protective T cells. High numbers of killed mycobacterium did not induce immune T cells. In addition, A/J mice inoculated with increasing numbers of viable M. avium (which still did not replicate) failed to develop protective T lymphocytes. Further studies indicated that no protective T cells were present in the M. avium-infected A/J mouse, although evidence for non-specific immunity in these mice was obtained. In addition, BCG (which grows progressively in A/J mice) stimulated a population of splenic T cells which protected recipient mice from subsequent infection with M. tuberculosis.

Animals↗

Release of a mitogenic factor by splenic Lyt 1+ T-cells from mice treated with SSM, an immunomodulator extracted from human type tubercle bacilli.

A production of the soluble factor activity in culture fluids of murine splenic mononuclear cells (SMNC) treated with SSM, an immunopotentiator extracted from Mycobacterium tuberculosis strain Aoyama B, was investigated. The soluble factor activity was determined as a mitogenic activity released from SMNC of mice previously treated with a 500 micrograms/kg dose of SSM (primed SMNC). The mitogenic activity was produced when primed SMNC were challenged in vitro with SSM at a concentration of 5 micrograms/ml. The activity was not produced in culture fluids of primed SMNC treated with anti-Thy 1.2 or anti-Lyt 1.2 monoclonal antibody plus complement followed by a challenge with SSM. However, the production of the activity was not affected by pretreatment of primed SMNC with anti-Lyt 2.2 monoclonal antibody plus complement. Since the non-specific resistance to tumors of mice stimulated with SSM was not demonstrated in mice depleted of Thy 1+ and Lyt 1+ T-cells, and Lyt 1+ T-cells from SSM-treated mice did not show any direct cytotoxic activities against tumor cells in vitro, the soluble factor released from Lyt 1+ T-cells by SSM stimulation may play an important role in developing the non-specific resistance of mice treated with SSM.

Adjuvants, Immunologic↗

Studies on the toxic effects of quartz and a mycobacterial glycolipid, trehalose 6,6'-dimycolate.

Quartz and trehalose 6,6'-dimycolate (TDM) both potentiate tuberculosis and have toxicities that depend on surface crystalline structures. Investigations were undertaken to determine if TDM can kill macrophages and produce hemolysis in a fashion similar to that of quartz and if quartz can induce granulomas similar to those induced by TDM. Trehalose 6,6'-dimycolate was spread as a molecular monolayer on the surface of tissue culture dishes adjacent to areas of uncoated plastic for comparison. Murine peritoneal macrophages were killed within hours by contact with the TDM monolayer, while those on adjacent areas of uncoated plastic remained viable and spread normally. The membranes of erythrocytes were also damaged by contact with the monolayer of TDM. This damage was inhibited by poly-2-vinyl-pyridine-N-oxide, an inhibitor of hydrogen bonding that blocks quartz induced hemolysis. These data suggest that TDM damages membranes via an adhesive mechanism similar to that of quartz. Furthermore, injections of quartz particles into mice induce acute granulomatous reactions similar to those induced by TDM. These data indicate that TDM and quartz have certain similarities in their mechanisms of action and that these similarities may be of importance in the pathogenesis of tuberculosis.

Animals↗

[Echographic aspects of peritoneal tuberculosis. Apropos of 14 cases].

Ultrasonic images are analyzed in 14 patients aged 5 to 60 years with peritoneal tuberculosis. Images frequently demonstrated an anterior subparietal zone of transonance of variable thickness, associated with masses exhibiting transonance and multiple frequency outlines englobing digestive echos with intra-abdominal enlarged glands and free or partitioned ascites. Less frequently observed images were those of digestive tube loops adherent to the wall, hepatic or splenic lesions. Correlations were sought between these ultrasonic signs and results of endoscopy. Diagnosis of peritoneal tuberculosis is emphasized as being based mainly on histology and bacteriology, but ultrasonography conducted initially can reduce the time for diagnosis, suggest the diagnosis, assess any extension of the disease, and evaluate effects of treatment.

Adolescent↗

Primary splenic lymphoma.

A middle-aged lady presented with fever and splenomegaly and had been provisionally treated for malaria, typhoid and tuberculosis. Diagnostic splenectomy was performed which revealed diffuse large cell lymphoma, B type, localized to spleen. Patient had remission of disease after splenectomy.

Biopsy, Needle↗

Protective efficacy of recombinant (Ag85A) BCG Tokyo with Ag85A peptide boosting against Mycobacterium tuberculosis-infected guinea pigs in comparison with that of DNA vaccine encoding Ag85A.

A recombinant form of BCG Tokyo with an Ag85A gene insert was administered once subcutaneously to guinea pigs and its protective efficacy was compared with that of a DNA vaccine encoding Ag85A from Mycobacterium tuberculosis administered twice to guinea pigs by epidermal gene gun bombardment. Vaccination with either the recombinant BCG Tokyo or Ag85A DNA significantly reduced the severity of pulmonary pathology and the number of pulmonary and splenic colony-forming units (cfu) (p<0.001). The recombinant BCG Tokyo was better than Ag85A DNA in terms of protective efficacy against M. tuberculosis. When immunogenic synthetic Ag85A peptide was further used as a booster together with recombinant BCG Tokyo (Ag85A) or Ag85A DNA, lung pathology was improved significantly and the number of pulmonary CFU was reduced significantly. Neither recombinant BCG Tokyo, Ag85A DNA, nor the parental BCG Tokyo protected the guinea pigs from hematogenous spread of tubercle bacilli to the spleen because splenic granulomas without central necrosis were recognized. The spleen tissues from guinea pigs vaccinated with recombinant BCG Tokyo or Ag85A DNA expressed IFN-gamma and IL-2 mRNA at significantly high levels (p<0.001) as evaluated by reverse transcription polymerase chain reaction. It is concluded that peptide boosting is important for the induction of higher protective efficacy by recombinant BCG Tokyo or a tuberculosis DNA vaccine and both recombinant BCG Tokyo (Ag85A) and Ag85A DNA vaccine induce Th2 cytokine mRNA expression significantly.

Acyltransferases↗

The mycobacterial heparin-binding hemagglutinin is a protective antigen in the mouse aerosol challenge model of tuberculosis.

The heparin-binding hemagglutinin (HBHA) of Mycobacterium tuberculosis is a surface-expressed adhesin that can affect binding to host cells via a unique, methylated, carboxyl-terminal, lysine-, alanine-, and proline-rich repeat region. It has been implicated in extrapulmonary dissemination of M. tuberculosis from the lung following the initial infection of the host. To assess the vaccine potential of this protein, purified preparations of HBHA were emulsified in a dimethyldioctadecylammonium bromide-monophosphoryl lipid A adjuvant and tested for the ability to reduce M. tuberculosis infection in the mouse aerosol challenge model for tuberculosis. The HBHA-containing vaccine gave a approximately 0.7-log reduction in CFU in both mouse lungs and spleens compared to adjuvant controls 28 days following challenge. Although a notable level of serum antibody to HBHA was elicited after three immunizations and the antibodies were able to bind to the surface of M. tuberculosis, passive immunization with monoclonal antibodies directed against HBHA did not protect in the challenge model. Compared to adjuvant controls, an elevated gamma interferon response was generated by splenic and lymph node-derived T cells from immunized mice in the presence of macrophages pulsed with purified HBHA or infected with live M. tuberculosis, suggesting that the effective immunity may be cell mediated. Efforts to construct effective recombinant HBHA vaccines in fast-growing Mycobacterium smegmatis have been unsuccessful so far, which indicates that distinctive posttranslational modifications present in the HBHA protein expressed by M. tuberculosis are critical for generating effective host immune responses. The vaccine studies described here demonstrate that HBHA is a promising new vaccine candidate for tuberculosis.

Aerosols↗

Immunization with extracellular proteins of Mycobacterium tuberculosis induces cell-mediated immune responses and substantial protective immunity in a guinea pig model of pulmonary tuberculosis.

We have studied the capacity of a selected fraction of Mycobacterium tuberculosis extracellular proteins (EP) released into broth culture by mid-logarithmic-growth-phase organisms to induce cell-mediated immune responses and protective immunity in a guinea pig model of pulmonary tuberculosis. Guinea pigs infected with M. tuberculosis by aerosol but not uninfected control guinea pigs exhibit strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. Guinea pigs immunized subcutaneously with EP but not sham-immunized control guinea pigs also develop strong cell-mediated immune responses to EP, manifest by dose-dependent cutaneous delayed-type hypersensitivity and splenic lymphocyte proliferation. EP is nonlethal and nontoxic to guinea pigs upon subcutaneous immunization. Guinea pigs immunized with EP and then challenged with aerosolized M. tuberculosis exhibit protective immunity. In five independent experiments, EP-immunized guinea pigs were consistently protected against clinical illness, including weight loss. Compared with EP-immunized guinea pigs, sham-immunized control guinea pigs lost 12.9 +/- 2.0% (mean +/- SE) of their total weight. EP-immunized guinea pigs also had a 10-fold reduction in viable M. tuberculosis bacilli in their lungs and spleens (P = 0.004 and 0.001, respectively) compared with sham-immunized control animals. In the two experiments in which some guinea pigs died after aerosol challenge, EP-immunized animals were protected from death. Whereas all 12 (100%) EP-immunized guinea pigs survived challenge with aerosolized M. tuberculosis, only 6 of 12 (50%) sham-immunized control guinea pigs survived challenge (P = 0.007, Fisher exact test). This study demonstrates that actively growing M. tuberculosis cells release immunoprotective molecules extracellularly, that a subunit vaccine against tuberculosis is feasible, and that extracellular molecules of M. tuberculosis are potential candidates for a subunit vaccine.

Aerosols↗

Characteristics of immunosuppressive macrophages induced in host spleen cells by Mycobacterium avium complex and Mycobacterium tuberculosis infections in mice.

The profile of generation and characteristics of immunosuppressive macrophages (M phi s), which suppress the ConA-mitogenic response of spleen cells (SPCs), in host CBA/JN mice during the course of Mycobacterium avium complex (MAC) and M. tuberculosis (MT) infections were investigated. In both infections, a marked reduction in ConA mitogenic response of splenic T cells was seen around 2 weeks after infection, and this was accompanied by generation of potent immunosuppressive M phi s in the SPCs of infected mice. The suppressive activity was much stronger in MT-infected mice than in MAC-infected ones. In both infections, the large part of the suppressive M phi s exhibited suppressor activity that depended on the arachidonic acid cascade, particularly mediated by prostaglandins (PGs), and the remainder showed the suppressor action independent from PGs. The unique finding of this study is that the generation of IL-2 reactive T cell populations in SPCs in response to ConA signal was markedly inhibited by the MAC- and MT-induced immunosuppressive M phi s, whereas the suppressive M phi s failed to reduce the IL-2-producing ability of splenic T cells. In any case, the present results indicate a close similarity in immunosuppressive M phi s induced by MAC and MT infections.

Animals↗

[Splenic pseudocystic. Report of a case].

Splenic pseudocysts represent 70 to 80% of the non parasitic cysts of this organ. Malaria, infectious mononucleosis, tuberculosis and t. pallidum infection are predisposing factors. Cystic characteristics are determined by CT-SCAN and ultrasound. Final diagnosis is achieved by hystological examination. This is a case report.

Adult↗

Immune responsiveness in mutant mice lacking T-cell receptor alpha beta+ cells.

Immune responses of mice with T-cell receptor (TCR)gamma delta+ T cells but lacking TCR alpha beta+ cells because of a disruption in the TCR alpha gene, were analysed against alloantigens, soluble protein antigen, killed Mycobacterium tuberculosis and exogenous superantigen. Rejection of skin allografts mismatched for classical major histocompatibility complex (MHC) plus multiple minor H antigens was virtually abrogated but the presence of mismatched Qa-1 non-classical MHC antigens on donor tissue resulted in a significant proportion of TCR alpha-/- mice rejecting such grafts. In view of the proposed role for gamma delta T cells in mycobacterial responses, and particularly against self- or mycobacterial heat-shock protein HSP 65, we examined these responses in TCR alpha-/- mice. Local responses after immunization were low in lymph nodes and no component of these was directed against mycobacterial HSP 65. However, splenic T cells from mutant mice responded strongly to either purified protein derivative (PPD) or M. tuberculosis. Our findings indicate that TCR alpha-/- mice are selectively compromised: while responses to (undefined) mycobacterial antigens were substantial, responses to some other target antigens such as MHC alloantigens and HSP 65, believed to be preferentially recognized by gamma delta receptors, were poor or absent. However, the fact that the mutant mice more readily rejected allografts that are mismatched for the non-classical MHC antigen Qa-1 in addition to classical MHC and minor-H incompatibility, indicates that in some mice the residual immune response, presumed to be by gamma delta cells, is sufficient to cause skin graft rejection and that recognition of non-classical MHC antigens may play an important part in the response.

Animals↗

Abdominal lymphadenopathy in intravenous drug addicts: sonographic features and clinical significance.

The sonographic features of abdominal lymphadenopathy in 35 patients with history of intravenous drug addiction were analyzed to assess their clinical significance. Of the 28 proven cases, 15 were due to reactive hyperplasia, 10 to infections, and three to neoplasms. Sonography was helpful in assessing the pathologic nature of these nodes. Most nodes attributable to reactive hyperplasia were small (less than or equal to 1.5 cm diam) and showed a characteristic distribution in the porta hepatis, celiac axis, and peripancreatic regions. Hypoechoic nodes were always pathologic, due either to tuberculosis or to neoplasm. Nodes larger than 1.5 cm in diameter and primarily involving the lower retroperitoneum, splenic hilum, and mesentery are highly suspicious for pathologic nodes, and appropriate biopsies are indicated for diagnosis.

Abdomen↗

Epidermal growth factor-binding protein in Mycobacterium avium and Mycobacterium tuberculosis: a possible role in the mechanism of infection.

Epidermal growth factor (EGF) is a potent mitogen for a variety of eukaryotic cells. EGF is found in a number of tissues and is prevalent in necrotic tissues and granulomata. The biological effect of EGF on mammalian cells is initiated by the binding to a specific receptor. Both Mycobacterium avium and Mycobacterium tuberculosis cause lung infections and localized or disseminated disease in both patients without AIDS and those with AIDS. Histopathologic studies show necrosis in the lung, liver, and splenic tissues of patients with disseminated mycobacterial infection. In the course of experiments to examine the effect of growth factors on macrophages, it was observed that M. avium and M. tuberculosis but not Mycobacterium smegmatis cultured in the presence of 5, 50, or 500 ng of EGF per ml grew significantly faster than mycobacteria cultured in the absence of EGF. 125I-EGF was found to bind to M. avium and M. tuberculosis, and the binding was competitively inhibited by unlabeled EGF. A receptor for EGF was identified on mycobacteria. Incubation of mycobacteria with EGF prior to infection of macrophage monolayers resulted in faster bacterial growth within macrophages compared with that of mycobacteria not incubated with EGF. EGF-binding protein was cloned and expressed in Escherichia coli, and subsequently the protein was purified and the N-terminal amino acids were sequenced. These results suggest that EGF is a growth factor for pathogenic mycobacteria in granulomatous tissues and within macrophages and might enhance growth rates of both intracellular and extracellular mycobacteria in the site of infection.

Amino Acid Sequence↗

Computed tomography of focal splenic lesions in patients presenting with fever.

INTRODUCTION: There is an awareness of the increased incidence of splenic abscess in Southeast Asia giving rise to unexplained fever. This study looks at the role of computed tomography (CT) in evaluating focal splenic lesions in patients presenting with fever. METHODS: 37 patients presenting with fever of unknown origin underwent CT and this study retrospectively analyses the findings in these patients. 13 patients also had associated abdominal pain. Patients with conditions at high risk for splenic infection include: diabetes mellitus in ten patients, leukaemia in seven patients, human immunodeficiency virus infection in five patients, intravenous drug abuse in six patients, and steroid therapy in two patients. No risk factors could be identified in seven patients. RESULTS: Splenic abscess was diagnosed in 28 patients. A range of infecting organisms was isolated but the most frequent were Staphylococcus aureus (eight), tuberculosis (four), Streptococcus (four), fungal (four) and melioidosis (four). No infecting organism could be identified in ten cases though in patients with leukaemia with multiple low attenuation areas, the cause was presumed to be fungal. Six patients were diagnosed to have splenic infarcts though differentiation from splenic abscess could be difficult; these patients were treated for an abscess and all had endocarditis. Three patients were subsequently diagnosed with lymphoma. Percutaneous abscess drainage was performed in five patients and splenectomy was carried out in six patients. CONCLUSION: CT proved to be very useful as it not only revealed the size and extent of any splenic abnormality but it assisted with guidance for percutaneous drainage, determined the site for biopsy, and provided follow-up after treatment.

Abscess↗

[Calcified splenic abscess, colonic fistula and ascites in a chronic carrier of Salmonella typhi].

We report the unusual case of a patient with chronic carriage of Salmonella typhi who presented with partially calcified splenic abscess linked to colic fistula and ascitis. The colic fistula could be secondary to ischemic necrosis by left colon compression due to spleen large abscess. Fistula was evidenced by abdominal computed tomography scan and confirmed by barium enema. The possible etiologies of ascitis are either tuberculosis or ascitic peritonitis secondary to the fistulisation; nevertheless, the role of segmentary portal located hypertension cannot be completely excluded. The splenic abscess was probably due to Salmonella typhi which was only isolated from stool specimens. The calcified splenic abscess was the evidence that the infection had occurred first. In addition, the isolation of Salmonella typhi in stool cultures six months after the subject had returned from the Comores proved the chronic carriage. Treatment by splenectomy and left colectomy was successful in this patient.

Abdominal Abscess↗

Acquired immunity to heavy infection with Mycobacterium bovis bacillus Calmette-Guérin and its relationship to the development of nonspecific unresponsiveness in vitro.

Mice heavily infected with Mycobacterium bovis bacillus Calmette-Guérin (BCG) rapidly generated an acquired cellular immune response to this infection, as characterized primarily by the emergence of a splenic T-cell population capable of passively transferring substantial levels of adoptive protection against a challenge infection with M. tuberculosis. The emergence of this protective T-cell population was temporally associated with considerable levels of DNA synthesis in vivo in both the spleen and liver, and with the development of an acquired capacity within the animal to express very high levels of nonspecific resistance to secondary intracellular bacterial infection. Concomitant with the emergence of this acquired response, splenic T cells from infected animals became severely unresponsive to blastogenic in vitro stimulation with the mitogen phytohemagglutinin, and possessed the capacity to suppress the responsiveness of normal T cells in cocultures. Both the unresponsiveness of T cells from infected mice and their immunosuppressive activity in vitro could be essentially ablated by supplementation of the tissue culture medium with a supernatant containing very high titers of the T-cell growth factor interleukin 2 (IL-2). Furthermore, T cells harvested from these animals at the peak of in vitro unresponsiveness exhibited a substantial capacity to absorb or consume IL-2 from IL-2-containing supernatants. It is hypothesized, on the basis of these findings, that mice heavily infected with BCG acquire an IL-2-dependent T-cell population within the spleen in response to this infection, and that the observed in vitro blastogenic unresponsiveness of spleen cells which contain this population may be an artefactual effect arising from the reduction or consumption of available IL-2 within the sustaining culture medium. The relevance of these findings is discussed with particular regard to clinical situations, such as lepromatous leprosy, in which restorative strategies involving the in vivo use of IL-2 are presently being postulated.

Animals↗

Excision biopsy of the spleen by ultrasonic guidance.

Excision biopsy of the spleen was performed in 32 patients, using a recently invented instrument, which consists of a spring-trigger system for firing the two parts of a Tru-Cut needle. The biopsies were carried out under the guidance of an ultrasonic scanner. This technique yields sufficient material of high quality for a proper evaluation both of individual cells and the internal structure of the spleen. Eight patients had parenchymal abnormalities found by ultrasonic scanning: five had multiple abnormalities whereas three had a single abnormal area. Seven of these eight patients had a pathological spleen biopsy, consisting of Hodgkin's disease (four patients), "high-grade" malignant non-Hodgkin's lymphoma (two patients) or tuberculosis (one patient). In the other 24 patients with a normal ultrasonic picture of the splenic parenchyma five biopsies were pathological (3 cases of hairy-cell leukaemia, 1 of Gaucher's disease and 1 of Hodgkin's disease). Side-effects were: slight to moderate pain (16/32 patients) and bleeding requiring transfusion (4/32 patients). In one of these patients splenectomy was performed because of the bleeding. Two of the patients with bleeding complications suffered from hairy-cell leukaemia. It is concluded from this study that excision biopsy of the spleen is a diagnostic method which in some patients can replace splenectomy. The method seems to be valuable especially in patients with parenchymal abnormalities shown by ultrasonic scanning.

Adolescent↗