The immunological network at the site of tumor rejection

The tumor mass irrespective of its type or location in the body has long been shrouded in mystery and even today we still have only a tentative handle on its secrets. Attempts to manipulate either the tumor cells per se or host-derived leukocytes have, on the whole, not been successful or at best questionable. The ability of the host to respond immunologically to TSTA is well documented, yet again attempts to manipulate this response have been disappointing. One of the problems has been a lack of knowledge concerning the tumor mass and its constituents, such as the intratumor leukocytes, and the significance of their presence to the biological properties of the neoplasm [8,9,80]. The purpose in studying the immunological network is, in part, to try to assign a function to these cells on the premise that lymphoid elements and macrophages have a potential role to play in recognition of TSTA. The advantage of adoptive immunotherapy model systems is that tumor rejection can be achieved under controlled conditions and this allows an analysis of the immunological network and its individual circuits. At the same time, valuable information on the mechanisms of action during adoptive immunotherapy and how best to improve therapeutic protocols is acquired.     

Histochemical detection of horseradish peroxidase activity in the rat by the vibratome-paraplast method

A method is described for the histochemical detection of horseradish peroxidase in Paraplast Plus embedded brain sections. The procedure uses 150-micron-thick Vibratome-cut slices of glutaraldehyde-paraformaldehyde-fixed brain tissue. Tetramethylbenzidine stabilized by diaminobenzidine/cobalt/H2O2 is used as chromogen. The Vibratome-cut slices are dehydrated through a graded series of acetone, cleared in toluol and flat-embedded in Paraplast Plus embedding medium. Serial sections can be cut as thin as 5-7 micron. The method is universal in its application and permits optimal visualization of labeled neurons with great morphological detail at the light-microscopic level.