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Biomedical subjects

L Tissi

Publications and source records attributed to L Tissi.

8 recordsLinked to original sources
PubMed1990

Experimental model of type IV Streptococcus agalactiae (group B streptococcus) infection in mice with early development of septic arthritis.

We have established an experimental murine model to gain insight into the pathogenicity and clinical features of type IV group B streptococcus (GBS) infections. Adult CD-1 mice were challenged intravenously with 10(7) type IV GBS cells, inducing systemic invasion. Most of the animals were able to clear the infection from the blood, brain, and lungs within 2 weeks and from the spleen and liver within 1 month. However, the animals were unable to clear the microorganism from the joints and kidneys during the 60-day observation period. About 80% of the mice challenged intravenously with type IV GBS manifested early septic arthritis, which evolved from an acute exudative synovitis to permanent lesions characterized by irreversible joint damage and ankylosis. Induction of persistent septic arthritis was dependent on the number and viability of microorganisms inoculated and was unrelated to the strain of type IV GBS and the growth phase of the inoculum. Type-specific antibodies of both immunoglobulin M and G classes could be detected by agglutination and enzyme-linked immunosorbent assay from days 7 and 14, respectively; immunoglobulin G antibodies persisted for more than 40 days. Complexes of antibodies and group- and type-specific antigens were detected in mouse sera 24 h after infection and persisted up to day 22. These results were obtained an experimental model of type IV GBS chronic infection with early development of septic arthritis, which could be useful in future studies of pathogenicity and immune mechanisms involved in the host resistance to this microorganism.

Animals↗
PubMed1988

Cell wall components of Candida albicans as immunomodulators: induction of natural killer and macrophage-mediated peritoneal cell cytotoxicity in mice by mannoprotein and glucan fractions.

Cell wall components from Candida albicans were compared to intact cells for their ability to induce natural cytotoxic immunoeffectors in the peritoneal cavity of mice. A soluble mannoprotein extract (MP) and an insoluble glucan fraction (GG) strongly stimulated the generation of peritoneal effectors capable of lysing YAC-1 and P-815 tumour cell lines in vitro. The anti-YAC-1 effectors were characterized as natural killer (NK) lymphocytes while the anti-P-815 effectors appeared to be activated macrophages. The activity of each fraction was typically dose-dependent and both fractions differed from whole cells in the kinetics of induction of cytotoxicity. However, the NK and macrophage effectors generated by these materials had similar functional and phenotypic properties, irrespective of the material used as inducer. No mannoprotein was detected in the insoluble glucan fraction GG. Hence, the immunoenhancing activity of GG could not be attributed to the presence of some MP or MP-like component. Mannan-rich fractions with low (less than 3%) protein content (M) or extracted by hot alkaline reagent (M-alk) were inactive as NK and macrophage inducers. Thus, the cell wall of C. albicans contains at least two distinct macromolecular complexes which mediate the induction in murine peritoneal exudates of cytotoxic effectors active against tumour cell lines.

Animals↗
PubMed1985

Induction of natural killer cell activity by inactivated Candida albicans in mice.

Injection of merthiolate-inactivated yeast form cells of Candida albicans into the peritoneal cavities of mice induced the appearance of a cytolytic effector population against YAC-1 tumor cell lines. This induction was maximally manifested in 5- to 8-week-old animals 3 to 4 days after injection of 2 X 10(7)C. albicans cells, and the peritoneal lytic population exerted its optimum cytotoxic effect after 4 h of incubation. No significant natural cytotoxic activity was generated by C. albicans in the bone marrow or thymus, whereas there was a slight, transient, but significant depression of natural splenic cytotoxicity. Experiments performed to characterize the natural cytotoxic population elicited by the inactivated yeast showed that the effectors were nonadherent, nonphagocytic cells. Moreover, the anti-YAC-1 lytic activity was partially sensitive to anti-Thy1.2 serum and was completely abrogated by treatment of peritoneal nonadherent cells with monoclonal anti-asialo GM1 antibodies. Finally, the peritoneal population of cytotoxic cells induced by C. albicans was fully susceptible to Ly5.1 plus anti-immunoglobulin G2a and complement lysis. Although different cell populations could be induced by inactivated C. albicans, all of our data support the view that the anti-YAC-1 activity was entirely attributable to natural killer lymphocytes.

Adhesiveness↗
PubMed1979

[Technic for studying antitetanus immunity].

The Authors carried out a research work on problems relating to technical aspects to the tetanus immunity tests. Some interesting conclusions have been reached: - Purified and diluted tetanus toxin is best preserved at - 20 degrees C, in pH 7.4 physiological salt solution added with 1% peptone. - Vaccination in small laboratory animals must be done injecting adsorbed anatoxin by a microsyringe, in order to avoid dilution of the original compound. - Protection test using low, i.v. toxin doses is more reliable than serological tests in assessing the acquired resistance level in immuno-prophylaxed animals. - Passive haemagglutination test is much more sensitive when done with turkey instead of sheep red blood cells.

Animals↗
PubMed1978

The state of antitetanus protection in the commune of Perugia.

A serological survey was carried out on the population in the Perugia district to assess the protection level against tetanus. The antitoxin titre was evaluated by indirect haemagglutination test in 983 sera from healthy subjects of both sexes and all age-groups. Only 285 males and 144 females, 33.47% of the subjects, had been immunized prior to the investigation. The research made it clear that the serological antibody level does not always correspond to the anamnestic data on previous immunization. Therefore, it appears that prophylactic treatment against tetanus should be based on objective data, that is, serum antibody titre, in all subjects at risk. This information, thanks to the indirect haemagglutination test, is not difficult to obtain.

Adult↗
PubMed1978

Haemagglutination antibody titre levels which give certain protection against tetanus toxin.

The lowest haemagglutination titre which gives safe protection against tetanus toxin, in sera of vaccinated subjects of both sexes and of all age groups has been assessed, by comparative haemagglutination and neutralization tests. It was established that sera with 1/32 haemagglutination antibody titre have a toxin neutralizing capability of greater than or equal to 0.1 I.U./ml. Lower haemagglutination titers do not assure protective capacity against tetanus toxin.

Animals↗
PubMed1977

Anti-Candida albicans precipitating antibodies in the sera of surgery patients.

In healthy subjects and in subjects undergoing surgical intervention for neoplastic and other diseases, the behaviour of precipitating antibodies against soluble Candida albicans natigens was studied. In 13,7% of healthy controls the Ouchterlony test was positive. In subjects suffering from intestinal tract neoplasia, the percentage of positive tests was 26,6% before and 66,6% after the intervention. In other two groups of patients affected by neoplasia, the per cent positive results of the tests after intervention were, respectively, 50% and 63,1%. Among non neoplastic patients undergoing surgical treatment, after intervention 35% too proved positive. The data were confirmed by P.E.T. (partigen elution test): specific anti-Candida IgG, and in some cases IgA, could be demonstrated. The diagnostic value of positive Ouchterlony's test against superficial soluble Candida antigens after surgical intervention has been discussed.

Antigens, Fungal↗