Modulatory effects of calf thymus extract on the subset of T lymphocytes in Trichinella spiralis-infected mice.

The immunotropic properties of calf thymus extract (TFX-Jelfa) is connected with the mimic action of the thymus to modulate the differentiation, maturation and function of prothymocytes and mature thymus dependent (T) cells. The studies were carried out on CFW male mice aged 3 months. The animals were infected per os with 200 larvae of Trichinella spiralis. TFX-Jelfa was administered i.p. at a dose of 10 mg/kg seven times at 24 hour intervals prior to infection. The percentage of CD4+ and CD8+ in suspension of splenocytes and mesenteric lymphonode cells by flow cytometry using monoclonal antibodies coupled with fluorescein isothiocyanate (FITC) or phycoerythrin (PE) were determined. At the same time, cryostat preparations, made from jejunum and muscle samples, were examined by the direct immunofluorescence method using FITC-labeled antibody to mouse CD4+ and CD8+. It has been found that infection with T. spiralis in mice decreases the percentage of CD8+ splenocytes, while the percentage of CD8+ mesenteric lymphonode cells does not change. However, in infected mice the percentage of CD4+ spleen cells and mesenteric lymphonode cells is increased. It has been also found that during the course of infection an increase in the number of CD8+ and CD4+ cells in the basal lamina propria of the intestines was observed. In infected mice, CD4+ lymphocytes were visible in the inflammatory infiltrates of the muscle tissue on the 14th day, whereas CD8+ lymphocytes were first observed a week later. Pretreatment with TFX does not change the inhibitory effect of infection on the percentage of CD8+ splenocytes, but potentiates the percentage of CD4+ spleen cells and mesenteric lymphonode cells increased by infection. Furthermore, administration of TFX prior to infection also potentiates the stimulatory effect of T. spiralis on the number of CD8+ and CD4+ in the basal lamina propria of the jejunum, and on the number of CD8+ cells in the inflammatory infiltrates of the muscle tissue.

Attempts of modification of apoptosis in the course of experimental trichinellosis in mice.

The influence of the some immunomodulators (PHA-P, TFX and dexamethasone) on the process of apoptosis, occurring in the course of trichinellosis in mice, has been studied. It has been found that PHA-P activates this process in the jejunum mucosa and prolongs it in the muscular inflammatory infiltration, whereas TFX has no influence and dexamethasone distinctly decreases the level of the apoptotic cells. The number of the intestinal trichinae on the successive days of infection was similar in all groups of animals, however, the number of the muscular larvae in the groups receiving immunostimulators was much lower and in the group treated with dexamethasone--a little higher than that in control. As in mice receiving PHA-P and TFX, the cellular inflammatory infiltration in the muscles was larger than that in control, and in the group to which dexamethasone was administrated--smaller, the authors think that it was extensiveness of the infiltration and not the level of the apoptotic cells that influenced the number of the outliving larvae.

Macrophages during infection with Trichinella spiralis in mice.

Behaviour of macrophages in experimental mice trichinellosis was investigated using the immunoenzymatic technique with monoclonal antibodies CD11b/CD18 within the framework of avidin-biotin-DAB. The maximum and earliest mobilization of macrophages 7 day post infection (dpi) was observed in the lamina propria of the intestinal mucosa. The highest level of macrophages in the muscles tissue was noted on day 21 of infection, however as early as in 28 dpi, their maximum level was observed inside the larval capsules. They line, especially between 35-42 dpi internal capsule surface.

The cells observed inside capsules of larvae in the course of experimental trichinellosis in mice.

In the course of trichinellosis in mice the numerous cells inside larval capsules were observed. Beginning on 14 day post infection (dpi) they were seen in about 7% of infected muscles fibers but at 21 dpi the percentage of capsules with the cells amounted to 77. In the next stage of infection the number of capsules containing cells continued to increase and reach almost 100% at 60 dpi. The identification of the cells was carried out by the indirect immunoenzymatic method using anti-CD4+, anti-CD8+ and anti-macrophage (Mac-1 antigen) monoclonal antibodies. In course of observation the level of CD4+ cells decreased from 11.3 to 0.7, of CD8+ from 17.7 to 3.0 and of macrophages from 71.0 to 23.1%. The most numerous CD4+ cells were seen at 14 dpi while the CD8+ and macrophages at 21 dpi. Beginning on 28 dpi negatively reacting cells inside larval capsules were also observed. The number of these cells increased from 23.8 to 73.2% at 60 dpi and their identification requires further investigations. The role and the function of all these cells are discussed.

[The influence of ricin on the course of experimental infections of mice with Trichinella spiralis]. / Wplyw ricinu na przebieg doswiadczalnego zarazenia myszy nicieniami Trichinella spiralis.

Mice received 5 ng of ricin 24 hours after infection (experiment I) or 1 ng of ricin twice, 24 hours and 17 days of infection (experiment II). Animals were killed in 7, 14, 21, 28, 35, 42 and 60 days after infection. In the jejunum and masseter muscle sections, CD4+ and CD8+ lymphocytes, mast cells and eosinophils were studied. Heavy suppression of CD8+ lymphocytes, strong eosinophils and less pronounced mast cells stimulation was observed in the jejunum of mice received ricin (experiment I). Worm expulsion in intestine was faster than in the control (opposite results in experiment II). The composition of cells infiltration in the muscle was in both experiments similar to the control, however, fewer CD4+ lymphocytes were observed in larva capsule and there were fewer muscle larvae. Therefore CD8+ cells are believed to take part in restricting only the muscle stage of trichinellosis.