Dose-dependent in vivo effect of Rhodiola and Echinacea on the mitogen-induced lymphocyte proliferation in mice.

Echinacea purpurea (EP) and Echinacea angustifolia (EA) are ones of the most important world's herbs with immunotropic activity. They were traditional medicinal plants used by North American Indians for the treatment of various illnesses. Now they are cultivated in many countries and are used mainly to treat respiratory tract infections. Rhodiola rosea (RR) and Rhodiola quadrifida (RQ) are medicinal plants originated from Asia and used traditionally as adaptogens, antidepressants, and anti-inflammatory remedies. We previously reported, that extracts of underground parts of RR and RQ exhibited immunotropic activity. We have demonstrated in pigs that in vitro RR or RQ supplementation of blood lymphocyte cultures stimulated T cell proliferative response to Con A in lower, and inhibited it in higher Rhodiola extract concentrations. The aim of this work was to evaluate the in vivo effect of these herbal remedies on the in vitro proliferative response of mouse splenic lymphocytes to another T-cell mitogen- Phaseolus vulgaris haemagglutinin (PHA). We have found significant stimulation of proliferative response, in comparison to the controls, in mice fed lower doses of tested remedies, and inhibition, no effect or lower stimulation, in mice fed higher doses of these drugs.

Competition of IL-1 and IL-1ra determines lymphocyte response to delayed stimulation with PHA.

BACKGROUND: Human peripheral blood mononuclear cells (PBMC) left in microcultures for 24h without mitogen do not respond to subsequent stimulation with PHA. They regain reactivity if the native culture medium is absorbed with other party lymphocytes or partially replaced with the medium from a PHA-stimulated culture. The observations suggest that, during the incubation, some inhibitory agent had accumulated in the culture medium. AIM: The study was performed to determine the nature of the observed phenomenon in respect of the possible role of monocytes and their products IL-1 and IL-1 receptor antagonist (IL-1ra), and to test for immunodiagnostic purposes the significance of quantifying the lymphocyte response to delayed stimulation with PHA in patients suffering from inflammatory prosesses. METHODS: Lymphocyte response to delayed stimulation with PHA, calculated as the lymphocyte-monokine interaction (LM) index, was determined in the microcultures of PBMC isolated from the blood of healthy donors or of patients with acute tonsilitis. The values of LM indices were compared with the ratios of IL-1ra/IL-1beta concentration estimated by enzyme-linked immunosorbent assay method in the culture supernatants. The influences of exogenous IL-1beta, IL-1ra, anti-IL1ra antibodies and antibiotic cefaclor on the monokine concentrations and on the values of LM index were tested. RESULTS AND CONCLUSIONS: The results show that the level of lymphocyte response to delayed stimulation with PHA (LM index) is inversely proportional to the ratio of IL-1ra/IL-1beta concentration in the culture. The low LM values at high IL-1ra/IL-1beta ratios in PBMC cultures from healthy donors, reversed proportions found in patients' PBMC (acute tonsilitis), and the cefaclor-induced reduction of LM value with correlated increase of the IL-1ra/IL-1beta ratio suggest that the LM assay may prove to be useful for immunodiagnostic purposes.

[Immunotropic effects of electromagnetic fields in the range of radio- and microwave frequencies]. / Immunotropowe wplywy pól elektromagnetycznych z zakresu radiofal i mikrofal.

On the grounds of reviewed literature and the results of own experiments, the authors present current views on the possible immunotropic influence of low energy electromagnetic fields, in the range of radio- and microwave frequencies. They conclude, that a more systematic and multidisciplinary investigations should be undertaken, comprising the wide spectrum of immune homeostatic tasks, including defensive, immunoregulatory and pro-regenerative capabilities of immune system exposed to rapid environmental spread of different electromagnetic emitters.

Desirable and undesirable immunotropic effects of antibiotics: immunomodulating properties of cefaclor.

The effect exerted on complex immunoregulatory functions of the immune system is an important criterion when selecting an antibiotic. When assessing the effect of an antibiotic on the immune system, one should also take into consideration the existence of functional relationships between the immune system and the nervous and hormonal systems. Among these three systems, there are common factors that modify biological processes. This makes it possible for the antibiotic not only to interact directly with the elements of the immune system, but also to exert indirect influences on potential neurotropic and endocrinotropic effects of the drug. Besides highly effective bactericidal activity, cefaclor demonstrates the ability to exert a favorable effect on some of the specific and non-specific immune responses and immunoregulation mechanisms, which may be important from a clinical point of view. Cefaclor enhances phagocytosis and bactericidal activity of granulocytes and macrophages, and favorably modifies the cooperation of monocytes and T lymphocytes. In this way, it corrects, both in vivo and in vitro, the immunoregulatory disturbances induced and aggravated by an infection. This effect is reflected by an improvement in the impaired immunoregulating activity of T lymphocytes, and is manifest both as an increase in suppressive activity and a correction of the monokine level ratio in relation to the decrease of proinflammatory monokine IL-1 and a relative increase of antiinflammatory IL-1ra. By normalizing the disturbed immunoregulation mechanism, cefaclor enhances the protective potential of the immune reaction while it also reduces the risk of immunogenic clinical complications such as persistent inflammatory conditions and allergic and/or autoaggressive responses. Such immunomodulating properties of cefaclor may be useful in the clinical treatment of patients with immune disorders leading to chronic inflammation and secondary allergic or autoaggressive reactions.

Plasma membrane cholesterol regulates human lymphocyte cytotoxic function.

Cell cholesterol is believed to be confined mainly to the plasma membrane. Treatment here of human peripheral blood lymphocytes with cholesterol-free and cholesterol-containing liposomes to effect, respectively, decreases or increases in cholesterol content measureable by chemical analysis, markedly altered effector functions of the cells. Depletion of cholesterol evoked inhibition of spontaneous and phytohemagglutinin-dependent lymphocyte cytotoxicity against allogeneic target cells. Opposite effects resulted from cholesterol enrichment, with PHA-dependent and antibody-dependent cytotoxicities increasing significantly. Treatment, instead, with the known inhibitor of cholesterol biosynthesis, 25-hydroxycholesterol, had suppressive effects like those resulting from lowering the cholesterol level physically by liposome treatment. Our data suggest that the plasma membrane cholesterol content of different categories of lymphocytes in man is both essential and regulatory for their cytotoxic function.

Thymosin induced changes in the cell cycle of lymphocytes from aging neonatally thymectomized rats.

The potential role of the endocrine thymus on the cell cycle of lymphocytes from aging neonatally thymectomized rats (LAT cells) was investigated using thymosin fraction 5. Thymosin rendered LAT cells similar to normal lymphocytes with regard to reconstituting the median S+G2 phase of the LAT cell. This is the first study to demonstrate an effect of thymosin on the cell cycle of lymphocyte populations.