saporin

Zhang Y, Berger SA (2004) Increased calcium influx and ribosomal content correlate with resistance to endoplasmic reticulum stress-induced cell death in mutant leukemia cell lines. J Biol Chem 279(8):6507-6516. doi: 10.1074/jbc.M306117200

Summary: Ca2+ plays a vital role in many cell processes. To investigate events associated with Ca2+ and endoplasmic reticulum (ER) stress-induced cell death, the authors developed a mutant cell line with resistance to several ER stress-inducing agents. One of the assays used to define the characteristics of this cell line was treatment of the cells with 3 µg/ml of Saporin (Cat. #PR-01) and subsequent analysis of protein expression. The suppression of ribosome function partially reversed the resistance to ER stress-induced cell death.

Related Products: Saporin (Cat. #PR-01)

I’Anson H, Sundling LA, Roland SM, Ritter S (2003) Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats. Endocrinology 144(10):4325-4331. doi: 10.1210/en.2003-0258

Summary: The authors hypothesized that hindbrain catcholamine neurons suppressed estrous cycles during chronic glucoprivation as an extension of their role in glucoprivic feeding. 42-ng bilateral injections of anti-DBH-SAP (Cat. #IT-03) were made into the paraventricular nucleus of female rats. Lesioned rats demonstrated inhibition of reproductive function during chronic glucose deficit, but not when a normal amount of glucose was available.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Saporin (Cat. #PR-01)

Q: You have stated that it was unlikely that saporin compounds or constituents would be excreted in urine or feces. However, you acknowledge that experimental data is lacking. Have there been any tests of animal urine or feces for saporin content? My animal care staff are concerned.

A: One of the reasons that no studies have been done on excretion of saporin is that there isn’t much on the theoretical side to cause concern. The primary issue is that the quantity used in mice (and even rabbits) is so small that when looked at in human terms (i.e., an animal 10 to 100-times larger), the dosage becomes insignificant. The LD50 for saporin in mice is 4-8 mg/kg;1 that would translate in humans to more than you’ll ever use! The immunotoxins, which contain only about 20% saporin by weight, really do not contain all that much saporin.

Looking at it another way, you need a concentration of about 100 nM to see even a vague hint of toxicity of saporin to cells. In human blood, that would correspond to 24 mg injected systemically into a person. It would be really expensive for anyone to get close to that number.

As far as urine and feces goes, the same calculations are appropriate, but there will be considerable degradation – the protein content in urine and feces is quite low and the probability is that you will be dealing with only saporin. Remember saporin is a plant protein that is related to proteins in foods that we eat (cucumbers, for example).

Q: Are there any studies which indicate what doses of saporin (by itself or compounded with an antibody) would be hazardous if ingested or injected (i.e. systemic dose level resulting in death or organ dysfunction).

A: When there is an antibody that does recognize a human epitope (the human p75-saporin immunotoxin that is used in rabbits, for example), at about 1 pM one sees the slightest bit of toxicity to cells. That translates, if injected by error into a human blood supply, to about 170 micrograms. That also is a gigantic dose. I am using very conservative numbers here, and the bottom line is that you cannot accidentally reach such dangerous levels under normal handling situations.

Having said all this, we still recommend that our customers take excellent care of themselves and we state clearly that precautions should be taken by people handling these materials, just as they should use precautions with all laboratory chemicals. Please refer to the data sheets provided with our products for safety instructions.

See: Saporin (Cat. #PR-01)

References

1. Stirpe F et al. Hepatotoxicity of immunotoxins made with saporin, a ribosome-inactivating protein from Saponaria officinalis. Virchows Arch B Cell Pathol Incl Mol Pathol 53(5):259-271, 1987.

Vulchanova L, Olson TH, Stone LS, Riedl MS, Elde R, Honda CN (2001) Cytotoxic targeting of isolectin IB4-binding sensory neurons. Neuroscience 108(1):143-155. doi: 10.1016/s0306-4522(01)00377-3 PMID: 11738138

Summary: Vulchanova et al. examine the role of IB4-binding neurons in nociception. IB4-SAP (Cat. #IT-10) was injected into rats (2 µg in left sciatic nerve). The resulting ablation of IB4-binding neurons provides evidence for their role in nociceptive processing and demonstrates a rapid compensatory response to signalling of acute pain.

Related Products: IB4-SAP (Cat. #IT-10), Saporin Goat Polyclonal (Cat. #AB-15), Saporin Goat Polyclonal, HRP-labeled (Cat. #AB-15HRP)

Waite JJ, Chen AD (2001) Differential changes in rat cholinergic parameters subsequent to immunotoxic lesion of the basal forebrain nuclei. Brain Res 918:113-120. doi: 10.1016/s0006-8993(01)02968-7 PMID: 11684049

Summary: 192-Saporin (Cat. #IT-01) is used extensively to eliminate the cholinergic neurons of the basal forebrain in rats. Waite and Chen compare the degree of loss between 192-Saporin (6 or 8.2 µg in 10 µl into left lateral ventricle) and control (Saporin, 1.82 µg into left lateral ventricle; Cat. #PR-01) using three methods: Assay of post mortem choline acetyltransferase activity, in vivo microdialysis of extracellular acetylcholine (ACh), and in vivo assessment of the rate of ACh synthesis. The infusion of saporin alone had no effect. After fifteen weeks, the authors report compensation of cholinergic activity in lesioned animals occurs in the hippocampus, but not in the frontal cortex as determined by measurement of the rate of ACh synthesis.

Related Products: 192-IgG-SAP (Cat. #IT-01), Saporin Goat Polyclonal (Cat. #AB-15), Saporin Chicken Polyclonal, affinity-purified (Cat. #AB-17AP), Saporin (Cat. #PR-01)

Gerashchenko D, Kohls MD, Greco M, Waleh NS, Salin-Pascual R, Kilduff TS, Lappi DA, Shiromani PJ (2001) Hypocretin-2-saporin lesions of the lateral hypothalamus produce narcoleptic-like sleep behavior in the rat. J Neurosci 21(18):7273-7283. doi: 10.1523/JNEUROSCI.21-18-07273.2001 PMID: 11549737

Summary: Orexin (also knows as hypocretin) peptides are produced exclusively by neurons in the lateral hypothalamus, however non-specific lesioning in this region has not produced narcoleptic-like sleep. Gerashchenko et al. use orexin-SAP (490 ng/0.5 µl; Cat. #IT-20) to specifically eliminate orexin neurons in rats. The treated rats displayed several sleep disturbances found in narcolepsy, including increased slow-wave sleep, and sleep-onset REM sleep periods. The data suggest that orexin-SAP can be used to create a model for narcolepsy in rats.

Related Products: Orexin-B-SAP (Cat. #IT-20), Saporin Goat Polyclonal, affinity-purified FITC-labeled (Cat. #AB-15APFL), Saporin Chicken Polyclonal, affinity-purified (Cat. #AB-17AP)

Rajagopal V, Kreitman RJ (2000) Recombinant toxins that bind to the urokinase receptor are cytotoxic without requiring binding to the alpha(2)-macroglobulin receptor. J Biol Chem 275(11):7566-7573. doi: 10.1074/jbc.275.11.7566

Related Products: Saporin (Cat. #PR-01)

Mantyh PW, Rogers SD, Honore P, Allen BJ, Ghilardi JR, Li J, Daughters RS, Lappi DA, Wiley RG, Simone DA (1997) Inhibition of hyperalgesia by ablation of lamina I spinal neurons expressing the substance P receptor. Science 278:275-279. doi: 10.1126/science.278.5336.275 PMID: 9323204

Related Products: Saporin (Cat. #PR-01), Saporin Chicken Polyclonal, affinity-purified (Cat. #AB-17AP), Saporin Goat Polyclonal (Cat. #AB-15), Saporin Goat Polyclonal, HRP-labeled (Cat. #AB-15HRP), SP-SAP (Cat. #IT-07), Antibody to NK-1 Receptor (Cat. #AB-N04)

Wenk GL (1997) The nucleus basalis magnocellularis cholinergic system: one hundred years of progress. Neurobiol Learn Mem 67(2):85-95. doi: 10.1006/nlme.1996.3757

Contestabile A, Stirpe F (1993) Ribosome-inactivating proteins from plants as agents for suicide transport and immunolesioning in the nervous system. Eur J Neurosci 5(10):1292-1301. doi: 10.1111/j.1460-9568.1993.tb00915.x