The inhibition of superoxide (02-) production by human peripheral blood polymorphonuclear leukocytes (PMNs) in the presence of oral treponemes, their cellular components, and their culture supernatants was investigated. Superoxide production was inhibited 56% by a 25-,ug/ml phenol extract of a human clinical isolate. Inhibition by culture supernatants of both the clinical isolate and a reference strain was related to the
Severe inflammatory lesions were induced in the periodontal tissues of the rat following the intragingival injection of lipoteichoic acid (LTA) from Streptococcus mutans. There was no difference in the severity and distribution of the lesions between nonimmunized rats and animals immunized against LTA after antigenic challenge. The lesions are characterized by the occurrence of granulation tissue, massive infiltration of PMNs, abscess formation, bone resorption, and new bone formation. Deacylated LTA and saline caused relatively mild inflammation, and no significant bone resorption or new bone formation was evident. The peak response was reached after 3 intragingival infections. The mechanisms by which LTA caused the pathological alterations in the rat periodontium and the possible relations of this experimental model to periodontal disease in the human are discussed.
Summary.-Urine of normal rats, pregnant animals and animals bearing chemically induced hepatoma was tested with antisera to foetoproteins by the double immunodiffusion technique. Antigens were not detected in the urine of normal rats. Alpha-foetoprotein was demonstrated in the urine of pregnant rats and hepatomabearing animals.
IN the course of study on the possibility of autoimmune mechanisms against tumour, the level of circulating antibodies to the autologous tumour cells was estimated by cell agglutination titres according to a technique previously developed in this laboratory (Pikovski, Tal, Schlesinger and Margoliash, 1957). It was soon found that cross agglutination occurred. It appeared that the sera from tumour patients contained a factor (AF) which could cause agglutination of, and be adsorbed by, tumour cells from a variety of sources. This paper represents an analysis of this phenomenon.
MATERIALS AND METHODS
Cell preparationCell suspensions were prepared from some human tumours, several normal human tissues and some mouse tumours by a previously described technique (Pikovski, Tal, Schlesinger and Margoliash, 1957). Suspensions of tissue cultures of HeLa cervical carcinoma, KB buccal carcinoma and Chang normal liver cells were also used. The preparation of the tissue culture suspensions is given in the following detail using HeLa cultures as the example.HeLa cultures were grown in Eagle's lact-yeast medium plus 15 per cent of normal human serum and horse serum, respectively, in milk bottles. After 7-8 days of growth, the medium was pipetted off, and the cell layer washed with 10 ml. of warm (370 C.) phosphate-buffered saline (PBS). The PBS was replaced by 10 ml. of 0-02 per cent Ethylenediamine Tetracetic acid (EDTA) in PBS devoid of Ca and Mg, and the culture kept at 370 C. for [15][16][17][18][19][20] minutes. This procedure loosened the cells from the wall of the culture bottle and the EDTA cell suspension was transferred to a test tube. Clumps of cells were dispersed by repeated pipetting with a fine Pasteur pipette, taking care to avoid foaming. The suspension was then centrifuged at 500 r.p.m. for 5 minutes. The supernate was carefully removed so as not to disturb the cell pellet. The cells were then resuspended in 8 ml. of warm RBS and centrifuged as above. The washed cells were counted and suspended in sufficient normal saline to give a concentration of 4 x 106 cells per ml.
Agglutination procedureSera were diluted fourfold with 0-2 M phosphate buffer (pH 7.0). The pH of the system was critical. 2 x 105 Cells were added to 0 4 ml. of serum dilutions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.