Regulation of lymphokine production in peripheral blood mononuclear cell cultures

An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.     

Modification of the skin feeding site by tick saliva mediates virus transmission.

A tick vector of Thogoto (THO) virus was shown to secrete a factor in saliva which potentiates the transmission of THO virus to uninfected ticks feeding on an apparently non-viraemic host. The effect of the saliva activated transmission (SAT) factor on the virus occurred at the site of inoculation in the skin and was apparent even when the virus was introduced 3 days after the SAT factor. The results suggest that tick saliva can play an important role in disease transmission by virtue of host modification at the site of feeding.     

Modification of the skin feeding site by tick saliva mediates virus transmission

A tick vector of Thogoto (THO) virus was shown to secrete a factor in saliva which potentiates the transmission of THO virus to uninfected ticks feeding on an apparently non-viraemic host. The effect of the saliva activated transmission (SAT) factor on the virus occurred at the site of inoculation in the skin and was apparent even when the virus was introduced 3 days after the SAT factor. The results suggest that tick saliva can play an important role in disease transmission by virtue of host modification at the site of feeding.     

Regulation of lymphokine production in peripheral blood mononuclear cell cultures

Summary An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.This work was supported by the Scientific Research Council, Ministry of Health, Hungary (Code No. 421 0304011/S).     

Kinetics of chemo-attraction of polymorphonuclear leukocytes towards N-formyl peptide studied with a novel polycarbonate (Nucleopore) membrane in the Boyden chamber

The motile responses of human polymorphonuclear leukocytes (PMN) to N-formyl-methionyl-leucyl-phenylalanine (FMLP) in the Boyden chamber using a new sparse-pore polycarbonate membrane (pores 3 micron in diameter and occupying 0.1% of surface area) were compared with those demonstrated by using a standard polycarbonate (Nuclepore) filtration membrane (pores 3 micron in diameter and occupying 5% of surface area). Motility of PMN in gradients of FMLP using the new membrane was not influenced by chemokinetic effects of the factor, and the 'background' migration of the cells was minimal. However, motility of PMN in gradients of FMLP using the standard membrane was found to be influenced by chemokinetic effects of the chemotactic factor, and the 'background' or 'control' migration (in the absence of chemotactic factor) of the cells was substantial. Greater directional migration of PMN according to steepness of the gradient of chemotactic factor was demonstrated with the use of the new membrane. The new membrane may be of considerable value in the further study of the chemotactic responses of PMN.     

Activation of complement by trypanosomes.

Factors exhibiting anti-complementary activity released from trypanosomes after incubation at 20 degrees C were described. The active material was shown to consume the first component of bovine complement. While the anti-complementary factor(s) from T. lewisi could activate bovine, human and guinea pig complement, the factor(s) from T. congolense was observed to activate bovine complement, but not guinea pig and only slightly human complement. The roles of complement activating factor(s) of trypanosomes in the pathology of the disease are discussed.     

Enhanced enzyme activity in concentrated salt solutions

Summary The enzyme activity of thrombin, -factor Xa-E and trypsin was enhanced in 1.0 M sodium citrate solution. Thrombin activated factor X. Synthetic substrate S-2222, designed for factor Xa, was hydrolyzed more rapidly with factor Xa or with thrombin in 1.0 M sodium citrate solution than in dilute salt solutions.Recipient of a Fogarty International Research Fellowship (TW-02743-02).     

Séparation sur séphadex G 100 de facteurs mucicriniques et mucimitiginiques à partir d'un extrait de muqueuse duodénale

Summary The mucicrin stimulating the hexosamine gastrointestinal secretion and extracted from porcine duodenum, was concentrated in the zone 7 using sephadex G 100. The molecular weight of 4000–5000 corresponds to this zone. An opposite activity was detected in zone 3. The factor from digestive mucous origin being able to diminish the hexosamine gastric secretion and not influencing the arterial pressure was called mucimitigin. The molecular weight of about 35000 corresponds to this factor.     

Activation of complement by trypanosomes

Summary Factors exhibiting anti-complementary activity released from trypanosomes after incubation at 20°C were described. The active material was shown to consume the first component of bovine complement. While the anticomplementary factor(s) from T. lewisi could activate bovine, human and guinea pig complement, the factor(s) from T. congolense was observed to activate bovine complement, but not guinea pig and only slightly human complement. The roles of complement activating factor(s) of trypanosomes in the pathology of the disease are discussed.This project is supported by National Research Council of Canada grant A 0068 and a grant from the International Development Research Centre.     

The effect of cobra venom factor (CVF) activation of the complement cascade on leukocyte circadian variation in the rat

Summary Administration of cobra venom factor (CVF) at different time periods over a 24-h-period produced a leukocytic response which varied according to the time of day the factor was given. The resulting leukocytic circadian rhythm was achieved by a marked variation and increase in the neutrophil population.This study was supported by U. S. P. H. S. Grant No. HL 16769 and Grant No. AI 09169.     

Serum immunoconglutinins and complement in systemicLupus erythematosus

Summary IK activity titrated by the sedimentation method in sera from patients affected with SLE was found to be negatively correlated with C4 and C3 complement factors levels. The significance of this data is discussed.Index of the abbreviations used: SLE, systemicLupus eritematosus; IK, immunoconglutinins; CH50, Total haemolytic activity; C4b, Complement factor connect with the complex AgAbCl; C3b, Complement factor connect with the complex AgAbClC4C2; C3PA, C3 proactivator in the complement activation by the alternate pathway implicated; KAF, Conglutinogen activating factor inactive the C3b in C3c and C3d. Antrypol, factor that makes C3b KAF-unreactive.     

Recherches sur le mécanisme de la rétraction du caillot et de la métamorphose visqueuse des plaquettes

Summary The concept, that viscous metamorphosis of platelets and clot retraction is initiated by thrombin and a dialyzable factor was confirmed. Under certain circumstances glucose acts as dialyzable factor. Clot retraction seems to depend upon the catabolism of glucose.     

Analysis of nucleotides bound to the ATP synthetase from spinach chloroplasts isolated under different conditions

Summary The total amount of bound adenine nucleotides in the coupling factor isolated from spinach chloroplasts and its distribution on AMP, ADP and ATP was analyzed after various incubation conditions. During purification of the coupling factor, the distribution of AMP, ADP and ATP is not altered. The coupling factor from deenergized membranes contains approximately 1 ADP, less than 1 ATP, and small amounts of AMP. During phosphorylation the pattern is changed and ATP becomes the dominant species. When exogenous ADP is lacking, phosphate is readily incorporated into ATP. Inhibition of adenylate kinase by AP₅A does not change the distribution pattern of the adenine nucleotides. The distribution pattern shows no integer numbers for the different nucleotides, suggesting that the coupling factor is present in different states in a statistical distribution.Acknowledgment: We thank the Swiss National Foundation for Scientific Research (grant 3.582.79) for generous support.     

New tigliane and daphnane derivatives from Pimelea prostrata and Pimelea simplex

From the methanol extract of Pimelea prostrata, prostratin (I) and 2 autoxidation products have been isolated. They are tigliane derivatives and relatively nonirritant on the mouse ear. The irritant pimelea factor P5 (IIa) also with a tigliane skeleton and related to mancinellin (IIb), as well as the irritant diterpene ester pimelea factor P1 (IIa, simplexin) with daphnane skeleton, were found to be present in both P. prostrata and P. simplex. Further the irritant homologue of simplexin, pimela factor IIIb was detected in P. prostrata. Some biogenetic consequences of these findings are discussed.     

Factor(s) from nonmacrophage bone marrow stromal cells inhibit Lewis lung carcinoma and B16 melanoma growth in mice

Bone marrow stroma produces positive and negative growth regulators which constitute the hematopoietic microenvironment. As many tumors metastasize to the bones, these regulators may also influence tumor growth. Hematopoietic cytokines may indeed exert both positive and negative effect on tumor growth. We report that, when mixed with tumor cells. adherent bone marrow cells inhibit primary tumor growth and metastases formation in mice transplanted with Lewis lung carcinoma or B16 melanoma. Peritoneal macrophages or lymph node cells did not exert any influence. The tumor inhibition was apparently due to soluble factor(s) released by marrow stromal cells. In cocultures with B16 melanoma cells, adherent bone marrow cells exerted a significant antiproliferative effect which was increased by previous culture of the bone marrow cells with granulocyte-macrophage colony-stimulating factor but not with macrophage colony-stimulating factor. Neither neutralizing antibodies against tumor necrosis factor-alpha, transforming growth factor-beta or interferon alpha/beta nor addition of Escherichia coli lipopolysaccharide to generate inflammatory cytokines could affect the antiproliferative effect of bone marrow stromal cells. The bone marrow stroma factor(s) which inhibit tumor growth might, therefore, be a novel growth regulator.     

The effect of mouse erythrocyte rosette forming lymphocytes on lymphokine production in T-cell cultures

Summary An enhancement effect of mouse erythrocyte rosette forming (MERF) cells on the production of migration inhibitory factor, chemotactic factor for neutrophils and skin reactive factor in T-lymphocyte cultures stimulated with the purified protein derivative of tuberculin was observed. We consider it likely that the MERF cells, possessing the appropriate cell surface constituents to construct an immunogenic moiety, present antigen on their surfaces to elicit lymphokine production.This work was supported by the Scientific Research Council, Ministry of Health, Hungary, Code No. 421030401 1/s     

The effect of mouse erythrocyte rosette forming lymphocytes on lymphokine production in T-cell cultures

An enhancement effect of mouse erythrocyte rosette forming (MERF) cells on the production of migration inhibitory factor, chemotactic factor for neutrophils and skin reactive factor in T-lymphocyte cultures stimulated with the purified protein derivative of tuberculin was observed. We consider it likely that the MERF cells, possessing the appropriate cell surface constituents to construct an immunogenic moiety, present antigen on their surfaces to elicit lymphokine production.     

Possible involvement of protein kinase C in the stimulation of amino acid transport by phorbol ester, platelet-derived growth factor and A23187 in Swiss 3T3 cells

Stimulation of amino acid transport induced by phorbol-12,13-dibutyrate, platelet-derived growth factor or A23187 was not observed in cells lacking protein kinase C. On the other hand, stimulation of transport by epidermal growth factor or insulin was not affected. These results suggested that the stimulation of amino acid transport is mediated by at least two separate pathways.