Dissociation between murine spleen cell mitogenic activity of enterotoxin contaminants and anti-tumor activity of staphylococcal protein A

Soluble staphylococcal protein A (SpA) in the form of high m.w. complexes with IgG has been shown to significantly inhibit the growth of Meth A fibrosarcomas in BALB/c mice. Although SpA reportedly is a potent T cell mitogen that can induce immune cell proliferation and production of humoral factors with anti-tumor activity, it has been suggested that mitogenic enterotoxin contaminants might be responsible for these effects. The purpose of the present study was to investigate the nature of SpA-induced cell proliferation and the relationship between mitogenicity and the anti-tumor effect that we observed in our mouse model. SpA stimulated the proliferation of a mixed population of splenic B and T cells from BALB/c mice, but activity did not require the presence of IgG in the culture medium. Furthermore, mitogenic activity could be inhibited completely by anti-SEA plus anti-SEB, but was unaffected by anti-SpA. HPLC-purified SpA was inactive while the mitogenic factor(s) had the same retention time as authentic enterotoxin and its activity was inhibited by anti-SEA and anti-SEB, but not by anti-SpA. Enterotoxin-free rSpA produced in Escherichia coli had the same IgG binding capacity as the staphylococcal product but was not mitogenic. These data indicate that SEA and SEB completely account for mitogenicity in SpA preparations. In contrast, we found that optimal concentrations of rSpA as well as crude and HPLC purified staphylococcal SpA were equally effective in inhibiting the growth of established Meth A fibrosarcomas demonstrating that SpA is responsible for antitumor activity without any apparent role for enterotoxins.     

Reconstitution of denatured E. coli alkaline phosphatase with E. coli ribosome.

E. coli alkaline phosphatase was denatured by physical/chemical means. In vitro reconstitution of this denatured enzyme was assisted by 70S E. coli ribosome, as shown by the recovery of its catalytic competence. Almost total recovery of activity of the totally inactivated enzyme was obtained in presence of equimolar concentration of 70S ribosome at 50 degrees C.     

Characterization and partial purification of <Emphasis Type="Italic">Candida albicans</Emphasis> Secretory IL-12 Inhibitory Factor

Background  

We have previously shown that supernatant from Candida albicans (CA) culture contains a Secretory Interleukin (IL)-12 Inhibitory Factor (CA-SIIF), which inhibits IL-12 production by human monocytes. However, the effect of CA-SIIF on secretion of other cytokines by monocytes is unknown, and detailed characterization of this factor has not been performed.     

Status of some free radical scavenging enzymes in the blood of myocardial infarction patients

Pro-oxidant and anti-oxidant systems and their levels have significant roles in occlusive vascular diseases. In the present communication, we have measured the levels of some representative anti-oxidant enzymes in the blood of the patients of myocardial infarction after reperfusion and compared them to age and sex matched healthy persons. Our findings show that the activities of anti-oxidant enzymes (viz. SOD, catalase and glutathione reductase) are significantly decreased whereas there is significant increase in the levels of malonaldialdehyde (a marker of free radical-mediated damage) in the patients. The findings point out that ischemic myocardial disorders are associated with excessive free radical generation and free radical-mediated damage of lipids.     

Sensory Neuron-Derived Eph Regulates Glomerular Arbors and Modulatory Function of a Central Serotonergic Neuron

Olfactory sensory neurons connect to the antennal lobe of the fly to create the primary units for processing odor cues, the glomeruli. Unique amongst antennal-lobe neurons is an identified wide-field serotonergic neuron, the contralaterally-projecting, serotonin-immunoreactive deutocerebral neuron (CSDn). The CSDn spreads its termini all over the contralateral antennal lobe, suggesting a diffuse neuromodulatory role. A closer examination, however, reveals a restricted pattern of the CSDn arborization in some glomeruli. We show that sensory neuron-derived Eph interacts with Ephrin in the CSDn, to regulate these arborizations. Behavioural analysis of animals with altered Eph-ephrin signaling and with consequent arborization defects suggests that neuromodulation requires local glomerular-specific patterning of the CSDn termini. Our results show the importance of developmental regulation of terminal arborization of even the diffuse modulatory neurons to allow them to route sensory-inputs according to the behavioural contexts.