targeted-toxins

Allen JW, Mantyh PW, Horais K, Tozier N, Rogers SD, Ghilardi JR, Cizkova D, Grafe MR, Richter P, Lappi DA, Yaksh TL (2006) Safety evaluation of Intrathecal Substance P-Saporin, a targeted neurotoxin, in dogs. Toxicol Sci 91(1):286-298. doi: 10.1093/toxsci/kfj143

Summary: SP-SAP (Cat. #IT-07) has been shown to reverse neuropathic pain behavior in rodents and prevent the formation of hyperalgesia. A safety study was done in beagles to further the use of this molecule as a human therapeutic. Animals received doses from 1.5-150 µg of SP-SAP as bolus intrathecal lumbar injections. Doses of 15 µg and above displayed significant loss of NK1r-expressing cells in lumbar Laminae II and I, but no adverse toxicity was observed at any dose.

Related Products: SP-SAP (Cat. #IT-07)

Read the featured article in Targeting Trends.

Foehr ED, Lorente G, Kuo J, Ram R, Nikolich K, Urfer R (2006) Targeting of the receptor protein tyrosine phosphatase beta with a monoclonal antibody delays tumor growth in a glioblastoma model. Cancer Res 66(4):2271-2278. doi: 10.1158/0008-5472.CAN-05-1221

Summary: The receptor protein tyrosine phosphatase ß (RPTPß) is overexpressed in astrocytomas, and is a potential target for tumor therapy. After testing antibodies against an extracellular domain of RPTPß in vitro with Mab-ZAP (Cat. #IT-04), two custom conjugates, 7E4B11-SAP and 7A9B5-SAP, were created by Advanced Targeting Systems. The authors tested the custom conjugates, using anti-DAT-SAP (Cat. #IT-25) as a positive control, and mouse IgG-SAP (Cat. #IT-18) as a negative control. The 7E4B11-SAP conjugate displayed significant antitumor activity in mice engrafted with U87 glioma cells.

Related Products: Mab-ZAP (Cat. #IT-04), Anti-DAT-SAP (Cat. #IT-25), Mouse IgG-SAP (Cat. #IT-18), Custom Conjugates

Easton A, Dwyer E, Pfaff DW (2006) Estradiol and orexin-2 saporin actions on multiple forms of behavioral arousal in female mice. Behav Neurosci 120(1):1-9. doi: 10.1037/0735-7044.120.1.1

Summary: Many aspects of female behavioral arousal in response to estrogens are not yet well understood. Here the authors examine the role of orexins as targets for estrogens. Female mice were treated with 10 ng of orexin-SAP (Cat. #IT-20) into each hemisphere of the lateral hypothalamus. The mice were then tested in different modes of behavioral arousal. Mice treated with orexin-SAP displayed decreases in sensory responsiveness and fearfulness concomitant with a reduction in orexin cell number.

Related Products: Orexin-B-SAP (Cat. #IT-20)

Saenz C, Dominguez R, de Lacalle S (2006) Estrogen contributes to structural recovery after a lesion. Neurosci Lett 392(3):198-201. doi: 10.1016/j.neulet.2005.09.023

Summary: The authors evaluated the trophic effects of 17ß-estradiol (E2) on cholinergic neurons of the basal forebrain after lesioning with 192-IgG-SAP (Cat. #IT-01). Ovariectomized female rats received 200 nl of 0.075 mg/ml 192-IgG-SAP followed by a subcutaneous pellet of E2, which was released over 60 days. Dendritic size in ovariectomized rats receiving the E2 was the same as in control animals, while ovariectomized rats receiving a placebo displayed a significant reduction in dendritic arborization.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Li A, Nattie E (2006) Catecholamine neurones in rats modulate sleep, breathing, central chemoreception and breathing variability. J Physiol 570(Pt 2):385-396. doi: 10.1113/jphysiol.2005.099325

Summary: Brainstem catecholamine (CA) neurons are thought to modulate the processing of sensory information and participate in the control of breathing. Using a 5 µg injection of anti-DBH-SAP (Cat. #IT-03), or a control injection of mouse-IgG-SAP (Cat. #IT-18) into the fourth ventricle, the authors investigated breathing frequency and wakefulness. The results suggest that CA neurons promote wakefulness, participate in central respiratory chemoreception, stimulate breathing frequency, and minimize breathing variability during REM sleep.

Related Products: Anti-DBH-SAP (Cat. #IT-03), Mouse IgG-SAP (Cat. #IT-18)

Chance WT, Dayal R, Friend LA, Sheriff S (2006) Possible role of CRF peptides in burn-induced hypermetabolism. Life Sci 78(7):694-703. doi: 10.1016/j.lfs.2005.05.083

Summary: Burn trauma has been associated with hypermetabolism and anorexia. Corticotropin releasing factor (CRF) elevates metabolic rate and elicits anorexia, while neuropeptide Y (NPY) reduces metabolic rate while stimulating feeding. After burn treatment, rats were injected with 2.5 µg CRF-SAP (Cat. #IT-13) into the third ventricle. Several parameters, including resting energy expenditure, NPY concentrations in the paraventricular nucleus, and CRFr-2 density were evaluated post-treatment. The results indicate that the CRFr-2 is important in maintaining hypermetabolism resulting from burn trauma.

Related Products: CRF-SAP (Cat. #IT-13)

Emgard M, Paradisi M, Pirondi S, Fernandez M, Giardino L, Calza L (2007) Prenatal glucocorticoid exposure affects learning and vulnerability of cholinergic neurons. Neurobiol Aging 28(1):112-121. doi: 10.1016/j.neurobiolaging.2005.11.015

Summary: Women at risk of preterm delivery are commonly treated with synthetic glucocorticoids such as dexamethasone and betamethasone. Here the authors examined adult rats that were prenatally exposed to glucocorticoids. After 2.5 µg intracerebroventricular injections of 192-IgG-SAP (Cat. #IT-01) or 0.44 µg of saporin (Cat. #PR-01), the rats were tested in a water maze pool. The evidence suggests that not only do prenatal glucocorticoids affect adult cognitive function, they also make cholinergic neurons more susceptible to challenges later in life.

Related Products: 192-IgG-SAP (Cat. #IT-01), Saporin (Cat. #PR-01)

Q: In a recent experiment using a saporin-antibody conjugate injected systemically we saw changes in dendritic cells that could be consistent with an LPS effect. Does ATS test for LPS and has this ever been identified as a problem before?

A: Yes, this can happen, but we here at ATS will swear innocence. One of our collaborators just reported the same thing (the first comment like that in several years), so I’ll tell you the story.

Generally our materials have a very low endotoxin content, on the order of less than 1 EU/mg protein. We check this occasionally because most of our customers provide an easy assay. That is, these things are often injected into the brains of rats, and they’ll die within a few minutes if there is an LPS (lipopolysaccharide) content such as you described. That would be disastrous for us, so we do pay attention to this issue. The recent situation was with an immunotoxin that was also injected systemically, and gave a response similar to what you’re stating. The material had been thawed and used in a set of experiments. Then, because of concerns about the effects of freezing and thawing, it was left in the refrigerator for a considerable period of time. It was then used in the experiments that gave the LPS-consistent result. We believe that this material was no longer sterile and that during the time between uses it grew bacteria. We went back and assayed the original material and it gave the usual less than 1 EU/mg value.

The bottom line is that once the sterility is broken, the material is a decent growth medium for bacteria (a protein in PBS). We filter sterilize all of our targeted toxins and package them in a sterile manner, but we do not add preservative. The thinking there is that in sensitive situations, a preservative can cause its own biological response/effect.

This situation causes us to print rather stringent use instructions: aliquot and store frozen at -20°C.

See: Targeted Toxins

Lai J, Zhang W, Badghisi H, Hruby VJ, Porreca F (2006) Featured Article: The biologically active cholecystokinin (26-33) peptide, [Tyr2-SO3]CCK-8, retains high affinity for CCK2 receptors after covalent conjugation to saporin. Targeting Trends 7(1)

Related Products: CCK-SAP (Cat. #IT-31)

Read the featured article in Targeting Trends.

See Also:

• Lai J et al. Featured Article: The biologically active cholecystokinin (26-33) peptide, [Tyr2-SO3]CCK-8, retains high affinity for CCK2 receptors after covalent conjugation to saporin. Targeting Trends 7(1), 2006.

Saurer TB, Carrigan KA, Ijames SG, Lysle DT (2006) Suppression of natural killer cell activity by morphine is mediated by the nucleus accumbens shell. J Neuroimmunol 173(1-2):3-11. doi: 10.1016/j.jneuroim.2005.11.009

Summary: In this work the authors investigated the role of dopaminergic projections to the nucleus accumbens in modulation of immune parameters such as morphine-induced suppression of splenic natural killer (NK) cell activity. Studies have indicated that acute exposure to opioids decrease NK cell-mediated cytotoxicity. Rats received bilateral 0.5 µg-injections of anti-DAT-SAP (Cat. #IT-25) into the nucleus accumbens shell. Treated animals showed no immunosuppression upon administration of morphine, indicating that dopaminergic neurons in the nucleus accumbens play a major role in this pathway.

Related Products: Anti-DAT-SAP (Cat. #IT-25)