Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of lysozyme dimer on humoral response to sheep erythrocytes (SRBC) and restoration of the response impaired by a single cyclophosphamide dose (200 mg/kg) were tested on mice. The effect of lysozyme dimer on the humoral response to SRBC in non-treated with cyclophosphamide mice was determined in relation to doses (0.2, 2, 20 or 200 micrograms/kg) and the time of the drug administration with respect to the antigen before or after SRBC immunization. Moreover, the effect of lysozyme dimer on the humoral response in cyclophosphamide-treated mice was studied depending on the dose applied and time of exposure to the drug in relation to SRBC. It has been found that lysozyme dimer potentiates the humoral response to SRBC in mice, resulting in an increased number of splenocytes producing haemolytic antibodies (PFC) and the total and 2-mercaptoethanol resistant level of anti-SRBC antibodies. A single exposure to lysozyme dimer gave the strongest stimulating action on SRBC when the doses of 2 or 20 micrograms/kg were administered 2 h prior to the antigen. The potentiating effect of the drug was reduced when it was administered 24 h before the antigen and also when single doses were as high as 200 micrograms/kg and as low as 2 micrograms/kg. Exposure to four doses of lysozyme dimer at 24 h intervals was more activating than a single injection. A strong potentiating effect on the specific response to SRBC was noted after four injections of lysozyme dimer at doses from 0.2 to 20 micrograms/kg. The effect of the drug did not depend on the time of exposure to the antigen. It has also been found that lysozyme dimer significantly reduces the suppressive effect of a high cyclophosphamide dose (200 mg/kg) on the humoral response of SRBC-immunized mice. The protective action of lysozyme dimer was dose- and time-dependent. The strongest protection was observed after three doses of 20 micrograms/kg administered prior to pharmacological immunosuppression. Reduction in the dose to 2 micrograms/kg and shorter treatment resulted in reduced protective effects. We have also found that the protective action of three doses of lysozyme dimer (2 or 20 micrograms/kg each) administered between cyclophosphamide injection and the antigen, or after antigen administration is weaker than such a treatment prior to cyclophosphamide immunosuppression.
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PMID:Effects of lysozyme dimer on humoral response to sheep erythrocytes in non-treated and cyclophosphamide-immunosuppressed mice. 946 1

The social environment of fish has a crucial role to play on the immune system and hence on the overall health status. Stressors of social origin such as dominance, subordination, and fight for mate have a major impact on the immune system of fish. The present study was designed with the objective of finding the effect of sex ratio of the population on the immune system of Oreochromis mossambicus. Groups of fish were maintained for 28 days in three different sex ratios i.e., (i) all-male (ii) all-female (iii) equal male and female (mixed). The specific immune response of fish was assessed by antibody response to Aeromonas hydrophila by ELISA and bacterial agglutination assay, and to SRBC by plaque forming cell assay. Nonspecific immune mechanisms were assessed in terms of serum lysozyme activity, production of intracellular reactive oxygen species (ROS) and reactive nitrogen species (RNS) by peripheral blood leukocytes. Disease resistance against live, virulent A. hydrophila was performed to assess the overall functional immunity. The results showed that antibody responses and numbers of antibody producing cells were increased in fish in the equal male and female sex ratio group compared to fish in monosex ratio groups. Similar enhancement was also observed in nonspecific serum lysozyme level and the ROS and RNS production. The host resistance test revealed that enhanced immunity in equal male and female sex ratio group was protective against A. hydrophila infection. The study clearly reveals positive and negative effect of sex ratio on the immune system of O. mossambicus.
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PMID:Effect of sex ratio on the immune system of Oreochromis mossambicus (Peters). 1625 5

Studies show that perfluorinated compounds cause various toxicological effects; nevertheless, effects on immune function and developmental endpoints have not been addressed at length. This study examined the effects of perfluorooctane sulfonate (PFOS) in white leghorn hatchlings on various developmental, immunological, and clinical health parameters. In addition, serum PFOS concentrations were determined by LC/MS/MS. Embryonic day (ED) 0 eggs were injected with either safflower oil/10% DMSO (control, 0mg/kg egg wt) or PFOS in safflower oil/10% DMSO at 1, 2.5, or 5mg/kg egg wt, and the chicks were grown to post-hatch day (PHD) 14. Treatment with PFOS did not affect hatch rate. Following in ovo exposure chicks exhibited increases in spleen mass at all treatment levels, in liver mass at 2.5 and 5mg/kg egg wt, and in body length (crown-rump length) at the 5mg/kg treatment. Right wings were shorter in all treatments compared to control. Increases in the frequency of brain asymmetry were evident in all treatment groups. SRBC-specific immunoglobulin (IgM and IgY combined) titers were decreased significantly at all treatment levels, while plasma lysozyme activity was increased at all treatment levels. The PHA skin test response decreased in relation to increasing PFOS dose. Serum concentrations where significant immunological, morphological, and neurological effects were observed at the lowest dose (1mg/kg egg wt) averaged 154 ng PFOS/g serum. These concentrations fall within environmental ranges reported in blood samples from wild caught avian species; thereby, verifying that the environmental egg concentrations used for the injections do indeed relate to serum levels in hatchlings that are also environmentally relevant. These data indicate that immune alterations and brain asymmetry can occur in birds following in ovo exposure to environmentally relevant concentrations of PFOS and demonstrates the need for further research on the developmental effects of perfluorinated compounds in various species.
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PMID:Developmental toxicity in white leghorn chickens following in ovo exposure to perfluorooctane sulfonate (PFOS). 1907 Dec 10

Anti-D can prevent immunization to the RhD Ag on RBCs, a phenomenon commonly termed Ab-mediated immune suppression (AMIS). The most accepted theory to explain this effect has been the rapid clearance of RBCs. In mouse models using SRBC, these xenogeneic cells are always rapidly cleared even without Ab, and involvement of epitope masking of the SRBC Ags by the AMIS-inducing Ab (anti-SRBC) has been suggested. To address these hypotheses, we immunized mice with murine transgenic RBCs expressing the HOD Ag (hen egg lysozyme [HEL], in sequence with ovalbumin, and the human Duffy transmembrane protein) in the presence of polyclonal Abs or mAbs to the HOD molecule. The isotype, specificity, and ability to induce AMIS of these Abs were compared with accelerated clearance as well as steric hindrance of the HOD Ag. Mice made IgM and IgG reactive with the HEL portion of the molecule only. All six of the mAbs could inhibit the response. The HEL-specific Abs (4B7, IgG1; GD7, IgG2b; 2F4, IgG1) did not accelerate clearance of the HOD-RBCs and displayed partial epitope masking. The Duffy-specific Abs (MIMA 29, IgG2a; CBC-512, IgG1; K6, IgG1) all caused rapid clearance of HOD RBCs without steric hindrance. To our knowledge, this is the first demonstration of AMIS to erythrocytes in an all-murine model and shows that AMIS can occur in the absence of RBC clearance or epitope masking. The AMIS effect was also independent of IgG isotype and epitope specificity of the AMIS-inducing Ab.
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PMID:Antibody-mediated immune suppression of erythrocyte alloimmunization can occur independently from red cell clearance or epitope masking in a murine model. 2512 24


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