The detection of IgG antibodies to silicone.

Following a recent report of an ELISA test for the detection of antibodies to silicone, we attempted to use the same assay in four patients with known exposure to silicone. These patients all gave similar positive results as did a number of control sera with no known silicone exposure. We conclude that this assay does not measure serum levels of antibodies to silicone.

Production of tumor necrosis factors alpha and beta by human mononuclear leukocytes stimulated with mitogens, bacteria, and malarial parasites.

Tumor necrosis factors alpha and beta (TNF-alpha and TNF-beta) are multifaceted polypeptide cytokines which may mediate some of the significant changes in cellular homeostasis which accompany the invasion of the mammalian host by viruses, bacteria, and parasites. Although it is well established that bacterial lipopolysaccharide is a potent inducer of TNF-alpha, there is still very little known of the types of agents which can trigger the production of TNFs in mononuclear leukocytes. Using an enzyme-linked immunosorbent assay for measuring TNF-alpha and TNF-beta, we examined the capacity of various T-lymphocyte and beta-lymphocyte mitogens as well as microbial components to stimulate production of these cytokines in culture.

Tetrandrine, a plant alkaloid, inhibits the production of tumour necrosis factor-alpha (cachectin) hy human monocytes.

Human mononuclear leucocytes (MNL) or the adherent fraction (monocytes) produced tumour necrosis factor-alpha (TNF-alpha) (by ELISA) in culture when stimulated with killed Staphylococcus aureus. The bisbenzylisoquinoline alkaloid, tetrandrine inhibited the capacity of MNL and monocytes to produce TNF-alpha at a concentration range of 0.1 to 5 micrograms/ml.

Depression of immunity to Naegleria fowleri in mice by selective depletion of neutrophils with a monoclonal antibody.

In an attempt to define the role of neutrophils in immunity to Naegleria fowleri in vivo, we examined the effects of treating immunized (with amoeba culture supernatant antigen) mice with the monoclonal antibody NIMP-R10, which binds to neutrophil complement receptor type 3bi (CR3) and causes selective neutrophil depletion in mice. Mice in the nonimmunized group challenged with amoebae all died by day 12, while 97% in the immunized group survived. By contrast, the immunized group treated with NIMP-R10 showed only 25% survival.

The role of antibody in immunity against experimental naegleria meningoencephalitis ('amoebic meningitis').

Mice immunized with amoeba culture fluid (ACF) from axenically cultured Naegleria fowleri showed marked protection against a lethal amoeba challenge, a result consistent with previous observations from this laboratory. The nature of this acquired resistance is not known. The data presented show that the degree of protection conferred to mice by immunization is related to the levels of antinaegleria antibodies.

An enzyme-linked immunosorbent assay for the quantitation of human IgG subclasses using monoclonal antibodies.

An enzyme-linked immunosorbent assay was established for the quantitation of human IgG1, IgG2, IgG3 and IgG4 using IgG subclass-specific monoclonal antibodies. The method could detect 1-10 ng/ml of the Ig subclasses. The technique is suitable for measuring IgG subclass concentration in sera of healthy adults and in supernatants from human lymphocytes cultured in the presence of pokeweed mitogen.

Depression of human polymorphonuclear leucocyte function by anti-malarial drugs.

The effect of the anti-malarial drugs quinine, chloroquine, pyrimethamine, mefloquine and quinacrine on human polymorphonuclear leucocyte (PMN) function was examined in vitro. In general, all drugs had their greatest effect on PMN iodination reaction and locomotion, intermediate effects on PMN hexose-monophosphate shunt activity, and least effect on PMN adherence. The most potent of these were pyrimethamine and mefloquine.

Inhibition of in vitro human lymphocyte response by the pneumococcal toxin pneumolysin.

The effects of pneumolysin, a sulfhydryl-activated cytolytic toxin produced by Streptococcus pneumoniae, on the in vitro human lymphocyte response was examined. The toxin, at concentrations of one to five hemolytic units per ml, caused marked inhibition of the response of lymphocytes to concanavalin A, phytohemagglutinin, pokeweed mitogen, and protein A. The response was assessed by measuring both [3H]thymidine incorporation and the ability of lymphocytes to produce immunoglobulins and lymphokine activity.

Activation of human complement by the pneumococcal toxin pneumolysin.

Highly purified pneumolysin (at a concentration of 10 micrograms/ml) caused significant activation of human complement, as measured by conversion of C3. Complement activation in the presence of pneumolysin was not observed in sera chelated with a combination of Mg2+ and ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid, and activation was only slight in C2-deficient sera. This suggests that the toxin is capable of activating the classical complement pathway.

Immunization with killed Acanthamoeba culbertsoni antigen and amoeba culture supernatant antigen in experimental Acanthamoeba meningoencephalitis.

Mice immunized with killed (sonicated) Acanthamoeba culbertsoni A-1 antigen displayed marked resistance to intranasal challenge with the amoeba. A primary immunization produced a survival rate of approximately 40%, and survival values of greater than 80% were obtained by multiple immunizations. Similarly mice immunized with fluids from A-1 cultures were highly resistant to infection.

Modification of polymorphonuclear leucocyte function by imidazoles.

The effect of five imidazole derivatives (metronidazole, tinidazole, clotrimazole, miconazole and ketoconazole) on human polymorphonuclear leucocytes (PMNL) was examined in vitro. Metronidazole and tinidazole had no apparent effect on either PMNL chemotactic response or PMNL fungal/bacterial killing. In contrast, clotrimazole, miconazole and ketoconazole inhibited PMNL chemotaxis.

Activation of the alternative pathway of complement by Acanthamoeba culbertsoni.

Normal human serum (NHS) contained an amoebicidal property for Acanthamoeba culbertsoni. Killing was quantitated by measuring the ability of the amoebae to undergo cell division subsequent to exposure to NHS, and also by microscopical examination. Plasma membrane disruption and extrusion of intracellular components occurred within 5-10 min following exposure to NHS.

Site of expression of immunity to Naegleria fowleri in immunized mice.

An experiment was performed which confirmed a previous finding that mice are protected against Naegleria fowleri infection by immunization with amoeba-free supernatant from amoeba cultures. Histological observations suggested that this protection is expressed mainly at the nasal mucosa and possibly results from the combined effects of polymorphonuclear leucocyte-mediated killing of the amoeba and mechanical elimination of the organisms by extensive shedding of necrotic epithelium.

The chemotherapeutic value of sulphadiazine in treatment of Acanthamoeba meningoencephalitis in mice.

The chemotherapeutic value of three sulphonamides, sulphamethizole, sulphamethoxazole and sulphadiazine, was examined in experimental Acanthamoeba meningoencephalitis in mice. Only sulphadiazine was capable of protecting mice challenged with A. culbertsoni A-1 strain.

Inhibition of mitogen-induced human lymphocyte responsiveness by polymixin antibiotics.

Polymixin antibiotics, polymixin B and polymixin E (colistin) inhibited the mitogen-induced lymphoproliferative response of human lymphocytes. Inhibition of the lymphocyte response to PHA, PWM and Con A was evident at a low concentration of 1 U/ml of antibiotics. Lymphocytes in which the signals for proliferation had occurred were similarly prevented from proliferating.

Activation of complement by Naegleria.

Neither Naegleria nor its culture supernatant was found to be directly chemotactic for human neutrophils. Interaction of Naegleria with human serum, however, resulted in the generation of a strong chemotactic stimulus. The reduction of serum activity by heat-inactivation indicated a dependence on serum complement for the interaction.

Immunization with live amoebae, amoebic lysate and culture supernatant in experimental Naegleria meningoencephalitis.

Immunization with two doses of live Naegleria fowleri produced a survival of 34% of mice compared to 0% in unimmunized controls, whereas multiple doses of live N. fowleri resulted in loss of protective immunity. In contrast, multiple doses of N.

Suppression of immunological responses in mice by treatment with amphotericin B.

The polyene antibiotic amphotericin B (AmB) caused a marked suppression of the cell-mediated immune response in mice. Similar treatment did not effect the humoral antibody response. The immunosuppressive property of the drug was related to its ability to inhibit the manifestation rather than the induction phase of the delayed-type hypersensitivity response.

Immunization with culture supernatant in experimental amoebic meningoencephalitis.

Mice were immunized with 0.25 ml culture supernatant intraperitoneally and challenged with 5 x 10(4) Naegleria fowleri intranasally. Survival rate was 11% after one and 25% after three immunizing doses, compared to 0% in controls.

Treatment of experimental Naegleria meningoencephalitis with a combination of amphotericin B and rifamycin.

The treatment of primary amoebic meningoencephalitis was examined using a mouse model. Rifamycin by itself was ineffective. However, a synergistic effect was observed when used in combination with amphotericin B.

Effect of mefloquine on the immune response in mice.

The effect of mefloquine, a new antimalarial compound, on the immune response in mice was studied in vitro and in vivo. Slight inhibition of mitogen-induced lymphocyte proliferative responses was observed at a concentration of 1 microgram/ml, and marked cytotoxicity at 4 microgram/ml. In contrast, a higher proportion of human lymphocytes remained viable at the same concentration of mefloquine.

Synergism between tetracycline and amphotericin B in experimental amoebic meningoencephalitis.

The efficacy of tetracycline and amphotericin B in the treatment of primary amoebic meningoencephalitis was studied by means of a mouse model. The results showed marked synergism between these two drugs. Mice who recieved 50 microgram amphotericin B daily succumbed to the infection with only 28.