Macrophage systems

Muramyl tripeptide phosphatidylethanolamine (MTP-PE), a synthetic analogue of muramyl dipeptide and an effective systemic macrophage activator, induces a variety of cytokines such as IL-1, IL-6, and TNE, as well as PGE2 (205). Preirradiation treatment of mice using MTP-PE encapsulated in Hposomes, which can intensify radioprotective abiHty, stimulates the monocyte/macrophage system and accelerates the recovery of hemopoietic cells. 

Liposomal drugs have been suggested to be the magic bullet of cancer therapy due to their ability to accumulate selectively in the tumour. The problem remains that not all cancers and patients respond in the same way. The drug actually delivered to the required site of action plays an important role in the response achieved, while the potential toxicity of the surface modified liposomes in the macrophage system have to be taken into account on chronic administration. 

In patients with multiple sclerosis, a qualitative cytological examination should always be carried out. Besides the finding of plasmocytic forms, which are considered to be one of the proofs of intrathecal synthesis of immunoglobulins, this examination also provides invaluable information concerning the reaction of the monocyte-macrophage system in the CSF compartment. It should be noted on the scope of biochemical examinations of cerebrospinal fluid in multiple sclerosis that it is most important to return to the simple and inexpensive method. 

Rhoades CJ, Williams MA, Kelsey SM, Newland AC. Monocyte-macrophage system and targets for immunomodulation by intravenous immunoglobulin. Blood Rev. 2000 14 14-30. 

These authors suggest that the multivalency of the lectins is an important factor in vacuole formation in these cells. However, we have seen that two of those lectins most active in the macrophage system, namely concanavalin A and wheat germ agglutinin, are unable to induce lysosomes in cultured fibroblasts. We are presently studying the properties of the lectins and the cells in order to more coiqpletely understand the mechanism of lectin induced accumulation of lysosomes in animal cells. 

The most significant adverse effect of glycosylated mammalian-derived rhM-CSF is a transient, dose- and schedule-related severe thrombocytopenia, which correlates with monocytosis and tjrpicaUy occurs after 7-10 days of treatment (7). Thrombocytopenia sometimes resolves despite continued administration of rhM-CSF and has usually not been sufficiently severe to cause bleeding. In other cases, a 50% reduction in the dose of rhM-CSF should be considered to allow treatment to be continued. The mechanism of rhM-CSF-induced thrombocytopenia does not involve suppression of hemopoiesis, but rather increased activity of the monocjTe/macrophage system in the liver and spleen (8). 

The antitumor properties of muramyl tripeptide are thought to be related to its immunoenhancing effects, in particular on the monocyte/macrophage system. Its most common adverse effect is a flu-like syndrome, usually during the first administration. In one trial in nine patients, four had mild to moderate respiratory distress, two of whom had pre-existing asthma and symptoms suggestive of asthma exacerbation (1). 

Robertson, O.H. and Uhley, C.G. (1938). Changes occurring in the macrophage system of the lungs in pneumococcus lobar pneumonia. J. CUn. Invest. 15, 115-130. 

Gelatin-chondroitin Granulocyte-macrophage Systemic anti-tumor [53]... 

Tinospora cordifolia has been shown to increase the colloidal carbon clearance in rats [17] suggesting global activation of the macrophage system. 

In clinical studies of Szmigielski (1982), P. granulosum KP-45 was shown to display immunomodulating, antineoplastic and antiviral effects, which were associated with the activation of monocyte-macrophage system, induction of interferon synthesis and/or activation of killer cells. Stimulation of interferon synthesis was also observed in human tissue cultures. The author suggested that these effects are mediated by the cell wall components, in particular, by peptidoglycans and teichoic acids. 

Adamson lYR, Bowden DH. Adaptive responses of the pulmonary macrophagic system to carbon. II. Morphologic studies. Lab Invest 1978 38 430-438. 

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