Macrophage participation in the polyclonal and specific response to T-independent antigen in vitro

Effect of adherent cells (macrophages on synthesis of total immunoglobulins (Ig) and specific antibody (Ab) in mice spleen cell culture stimulated by Vi-antigen Salmonella typhi has been studied. Ig and Ab in culture medium were determined by ELISA technique 96 hours after introducing the antigen into cell culture. The adsorption of analysed samples and reference antiserum on antigen coated microplates at pH 3.5 results in reducing nonspecific protein adsorption and promotes quantitative analysis Ab synthesized in vitro. The level of Ab produced in antigen stimulated spleen cell culture during 96 hours after antigen introduction is less than 2% of all synthesized Ig. Removal of most macrophages from spleen cell population results in a considerable decrease of specific and polyclonal immune responses. The basal Ig level in spleen cell culture (without antigen influence) does not decrease after removal of macrophages.     

Predicting biomass of bilberry (Vaccinium myrtillus) using rank distribution and root-to-shoot ratio models

Plant Ecology - Investigation of relationships between biomass of different plant compartments is important because their varying turnover rates affect the amount and composition of aboveground and...     

Interleukin-1 in realisation of stress-induced changes in functions of the immune system

Stress influences of different duration and intensity induce production of a lymphocyte-activating factor (LAF) by murine peritoneal macrophages, and enhancement of Interleukin 1 (IL-1) level in the murine blood, inducing no alterations in the thymocyte reaction to concomitant action of the IL-1 beta which correlates with changes in the value of humoral immune response. The data obtained are in agreement with differently aimed stress-induced alterations in the activity of the membrane neutral sphingomyelinase: the key enzyme of the sphingomyelin cascade, in the membrane P2 fraction of the brain cortex. The IL-1 seems to participate in physiological mechanisms of realisation of stress reactions on the levels of its production and biological action on target cells as well as of the sphingomyelin pathway of its signal transduction in nerve tissue.     

Activation of neutral sphingomyelinase by IL-1beta requires the type 1 interleukin 1 receptor

The cytokine interleukin 1beta (IL-1beta) plays an important role in host defence reactions and neuro-immune interactions but it is still not clear which of the two interleukin 1 receptor subtypes is coupled to activation of neutral sphingomyelinase (nSMase) by IL-1beta. To investigate involvement of neutral sphingomyelinase (nSMase) in central IL-1beta effects we used P(2)fractions of brain cerebral cortex from wild-type mice and mice deficient in the type 1 IL-1 receptor. IL-1beta (human, recombinant) was shown to activate, in a dose-dependent manner, nSMase in the P(2)brain fraction of the wild-type mice while in the knock-out mice the stimulatory effect of IL-1beta on nSMase was absent. In the presence of an IL-1 receptor antagonist (IL-1ra), IL-1beta did not activate nSMase either in the cortex of wild-type or knock-out mice. These data suggest that nSMase, a key enzyme of the sphingomyelin signal transduction pathway, might be involved in IL-1beta signalling in the brain and that activation of the enzyme requires the IL-1 receptor type 1.     

Effect of gonadotropins,thyrotropin, and adrenocorticotropin on the development of 12-day chick embryonic gonads

Summary Gonadotropins (FSH+LH) and thyrotropin (TSH) stimulated the development of 12-day embryonic gonads, whereas adrenocorticotropin (ACTH) did not show any significant effect. It is concluded that the gonads of 12-day chick embryos have the capacity to respond to both gonadotropic and thyrotropic stimulation. This suggests that at the time when the hypothalamo-pituitary-thyroid axis begins to develop, the capacity of gonadal receptors to distinguish between gonadotropins and thyrotropin has not been established.