Petr Sima

Lytic activities in coelomic fluid of Eisenia foetida and Lumbricus terrestris

Coelomic fluids of the two earthworm species E.foetida (E.F.) and L.terrestris (L.T.) have not only the ability to lyse various vertebrate erythrocytes but also to digest vertebrate serum proteins. Both activities are carried by different molecules since hemolysis but not proteolysis was inhibited by simple sugars. In contrary, proteolysis was blocked by PMSF which did not influence hemolysis. Coelomic fluids of E.F. digest effectively vertebrate serum proteins (PIgG, HSA) but not the proteins of L.T. coelomic fluids. The proteolytic activity was detected in approximately 40 000 mol. wt. fraction. After digestion proteolytic fragments were analyzed by immunoelectrophoresis, SDS-PAGE and TCA precipitation. Two of the fragments reacting with PIgG antisera remained intact even after 120 h digestion.

The effects of β - glucan on fish immunity

Administration of glucans through immersion, dietary inclusion or injection has been found to enhance many types of immune responses, resistance to bacterial and viral infections and to environmental stress in many fish species. Although the efficacy of the glucan varies with types and administration, glucan used as an immunomodulatory and mostly immunostimulatory additive has been found satisfactory in eliciting immunity in commercial aquaculture. Development of more efficient administration methods will facilitate the routine and prophylactic use of glucans as natural immunostimulants of fish. Using a PubMed search, this review has an extensive literature on glucan in fish immunity.

Response to parenteral stimulation in earthworms L. terrestris and E. foetida

Injection of different protein molecules into the coelomic cavity of Eisenia foetida (E.F.) and Lumbricus terrestris (L.T.) markedly stimulated proteosynthesis. A similar but less pronounced increase of coelomic proteins was induced by phosphate buffered saline (PBS). In the coelomic fluids of stimulated animals a protein was detected which significantly bound to the 125I or peroxidase labelled protein molecules used for stimulation. The maximal binding occurred on day 8 after primary stimulation. A greater increase was observed after secondary stimulation. The degree of binding specificity appeared to be much lower than that of vertebrate lymphocyte receptors or antibodies.

The effect of bilirubin on the Fc receptor expression and phagocytic activity of mouse peritoneal macrophages.

The effect of bilirubin on the phagocytic activity of mouse peritoneal macrophages and on the expression of Fc receptors and receptors for SRBC was studied. Intraperitoneally administered bilirubin influenced the expression of Fc receptors for IgM, IgG2B, IgA and IgE, whereas the expression of other receptors as well as the phagocytic activity of peritoneal macrophages remained unchanged. The possible mechanism of the effect of bilirubin on Fc receptors is discussed.

Repeated antigenic challenge induces earthworm coelomocyte proliferation

Annelids are able to protect themselves against foreign materials by natural and acquired cellular immunity. The aim of this study was to characterize the kinetic of antigen induced proliferation of earthworm coelomocytes. The proliferative activity of free coelomocytes of Eisenia foetida decreased after a second contact with the same antigen. Precursor cells in the mesenchymal lining of the coelomic cavity responded to stimulation immediately. These results indicate that for a successful triggering of the proliferative response of the free coelomocytes repeated contact with stimulating agents is needed.

The immunosuppressive effects of bilirubin

The strong effects of bilirubin on various levels of the immune system are multifactorial. Concerning the mechanisms of these effects, we hypothesize that the primary causes of the described actions of bilirubin are the direct interaction of bilirubin molecules with cell membranes.

The effect of Bilirubin on the phagocytic activity of mouse peripheral granulocytes and monocytesin vivo

Using anin vitro phagocytic assay with synthetic 2-hydroxyethylmethaerylate copolymer particles, the phagocytic activity of leukocytes of bilirubin-treated mice (85 and 170 μmol/L in 0.5 mL intraperitoneally) was studied. Bilirubin treatment significantly stimulated the phagocytosis of both peripheral blood granulocytes and monocytes; the increase of phagocytosis persisted for 6 h after bilirubin injection. The potential immunostimulating and/or immunotoxic effect of bilirubin is discussed.

The Effects of β-Glucan on Pig Growth and Immunity

With increasing amounts of data showing significant immunostimulating effects of glucan, it is not surprising that attention is also focused on commercially farmed animals. Despite marked progress, development of more efficient uses of glucan in pig farming still needs substantial additional research.

Effects of bilirubin on murine peritoneal and spleen cells

The effect of bilirubin on murine peritoneal and spleen cells was investigated. Bilirubin was found to have a strong and rapid effect on the expression of various kinds of Fc receptors on peritoneal macrophages. Significant changes were observed 30 min after the infection of bilirubin. The return to normal values was not observed earlier than after 24 h. The effect of bilirubin on Fc receptor expression of splenic macrophages was less pronounced. Expression of la antigen on macrophages was not influenced by bilirubin. The changes in percentage of slg+ and Thy 1.2+ lymphocytes reflect a change in the ratio of T to B cells in the peritoneal cavity, as bilirubin caused 40% increase in numbers of B cells and a similar decrease in numbers of T cells. The percentage of splenic B lymphocytes was not influenced by bilirubin injection; but the ratio of T helper to suppressor cells was altered.

Changes in the arrangement of the microtubule system of murine peritoneal cells after an antigenic stimulation

We determined two characteristic morphological patterns typical for the organization of microtubule systems of murine peritoneal macrophages and lymphocytes. A small number of both cell types formed uropods with an axial bundle of microtubules. This number remains practically unchanged during 48 h of cultivation in non-antigenic environment but grows rapidly in the presence of an antigen.