News in a nutshell

This week’s news includes the surprising immune rejection of induced pluripotent stem cells, a WHO gathering to discuss the fate of two remaining stocks of smallpox virus, the use of AIDS drugs to prevent HIV transmission, Salmonella sweeping across US labs, the debate over why the blind have an improved sense of touch, and a trick used by tarantulas to keep from falling.

Stem cell setback

Human iPS cells, Image: Kyoto University / AP

Because induced pluripotent stem (iPS) cells are made from a patient’s own skin cells and are thus genetically matched, scientists have assumed the cells would not trigger a patient’s immune response. But Yang Xu at the University of California, San Diego, and colleagues overturn this dogma, demonstrating that iPS cells trigger immune reactions when implanted into mice. In some cases, the implanted cells were completely destroyed by the mouse’s immune system. The immune response “is the same as that triggered by organ transplant between individuals,” Xu told ScienceNow. The study was published Friday (May 13) in Nature.

Destroying smallpox stocks

This week, health ministers from the World Health Organization’s member countries will gather to decide the fate of the last two known remaining stocks of smallpox virus. Scientists and health officials are divided over whether the final stocks of the virus should be kept for research into drugs and vaccines, in case of a reappearance of smallpox, or whether they should be destroyed to eliminate any risk of accidental outbreak.

The disagreement is a consequence of differing perceptions of risks and benefits among developed and developing countries, David Heymann, chairman of the board of UK Health Protection Agency, told Nature. Many poorer countries see smallpox research as a potentially dangerous luxury, he noted, while developed countries want to continue research due to fear that the virus could be used in a deliberate terrorist attack.

Preventing HIV transmission

A large, randomized trial involving over 1,700 couples in 9 countries has found that early antiretroviral treatment lowers an HIV-infected individual’s risk of transmitting the virus by 96 percent. The results, announced by the National Institute of Allergy and Infectious Disease last Thursday (May 12), were so convincing that an independent panel monitoring the research recommended they be released four years before the study had been scheduled to end, the Wall Street Journal reports. “The divorce between treatment and prevention is not real,” Michel Sidibé, head of the Joint United Nations Programme on HIV/AIDS, told ScienceInsider. “Treatment can reduce the number of new infections, which can increase the value of treatment.”

Salmonella hits US labs

An outbreak of lab-associated Salmonella infections is prompting health officials to examine laboratory safety protocols. Seventy-three infections across 35 states, tracked back to laboratories, caused illness and one death between August 2010 and March this year, the Centers for Disease Control and Prevention (CDC) reported on 28 April. Some of the infected individuals never visited a lab, but lived with someone who worked there, suggesting the lab worker carried the bacteria home on items of clothing or bags, the CDC’s Casey Barton Behravesh told Nature. It raises the question of whether use of this pathogenic Salmonella strain in teaching labs is necessary, he noted. For now, the outbreak seems to have ended, with the number of reported new infections dropping to the usual baseline of 0–4 per week.

An improved sense of touch

The blind have a better sense of touch than those with sight because of daily dependence on touch, not because the brain compensates for vision loss, new research suggests. Published on Wednesday (May 11) in the Journal of Neuroscience, researchers at McMaster University in Ontario found that blind participants outperform sighted individuals on all fingers, but blind Braille readers show particular sensitivity on their reading fingers, and both sighted and blind participants performed equally when the lips were tested for sensitivity. “There have always been these two competing ideas about why blind people have a better sense of touch,” said author Daniel Goldreich in a press release. “We found that dependence on touch is a driving force here.”

Wikimedia Commons, Arjun

Silk-shooting tarantulas

Tarantulas, large spiders that do not have the anchors that daintier spiders use to cling to vertical surfaces, shoot silk safety threads from their feet to reattach themselves to surfaces when they lose hold. The results, published in The Journal of Experimental Biology, support a 2006 paper that first suggested tarantulas release silk threads from their feet, a report that was refuted when another group found no evidence of the silk.

Related News Stories:

  • iPS cells yield live mice
    [23rd July 2009]
  • Piggybacking to pluripotency
    [1st March 2009]
  • Salmonella vaccine lift-off
    [2nd June 2008]
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    Filed under News in a Nutshell.

    6 comments

    1. Mike says:

      Interesting news this week! I hope that everyone had both a great weekend and Nurses’ Day, is having a great week and I hope that they have another great weekend!

    2. Shi V. Liu says:

      I am not surprised at all with this finding of immune rejection of iPSCs. As a matter of fact, I have specifically pointed out a severe flaw in previous publications claiming success of iPSC-based cell therapy. For example, in my article “Questions Regarding iPSC-based Correction of Hemophilia” which was rejected by PNAS but published in Top Watch ()4:506,2009; http://im1.biz/albums/userpics/10001/TW2009V4N1A2_PNAS.htm ), I stated:”why a study aimed at showing a circumvention of the immune rejection barrier by using iPSC-based therapy would still use sub-lethally irradiated mice as the recipients?”
      Now, my worry has just been confirmed.
      So iPSCs are indeed incorrectly programmed stem cells that are even disliked by its source organism. What an irony for the whole iPS research!.

    3. Shi V. Liu says:

      This Nature “discovery” is not a new discovery. I have published many criticisms on using immuno-suppressed animals for demonstrating “successful ” iPSC-based therapy. For example, I have indicated (Top Watch 4:506,2009; http://im1.biz/albums/userpics/10001/TW2009V4N1A2_PNAS.htm) the experimental flaw in using sub-lethally irradiated mice for demonstrating a circumvention of the immune rejection barrier by using iPSC-based therapy (PNAS 106, 808-813, 2009)

      In addition, 《Biology Direct》published a paper“Multipotent adult germ-line stem cells, like other pluripotent stem cells, can be killed by cytotoxic T lymphocytes despite low expression_r of major histocompatibility complex class I molecules ”(HTM,PDF)。This paper clearly shows that“All pluripotent stem cell lines were killed in a peptide-dependent manner by activated CTLs derived from T cell receptor transgenic OT-I mice”。The conclusion of this paper is “Pluripotent stem cells, including maGSCs, ESCs, and iPSCs can become targets for CTLs, even if the expression_r level of MHC class I molecules is below the detection limit of flow cytometry. Thus they are not protected against CTL-mediated cytotoxicity. Therefore, pluripotent cells might be rejected after transplantation by this mechanism if specific antigens are presented and if specific activated CTLs are present. ”

      I have published my comment on this paper even in Chinese (http://blog.sina.com.cn/s/blog_502041670100eisp.html).

    4. H. Fletcher says:

      Did the authors whose stem cells were rejected rule out serum effects? Someone years ago pointed out that cultured cells could incorporate proteins from serum in medium into their membranes, that it could persist for a long time and was diluted by about half at each cell division. It could also produce an immune response. The cure was to use serum free medium. The paper cited as the method is not much help, but used foetal bovine serum (FBS). If the recent paper did the same it is possible that the stem cells carried bovine markers.

    5. Shi V. Liu says:

      By carefully reading this “new” discovery reported in Nature, I realized that my original discoveries on iPSCs have all been proved here.
      Make no mistake on this: I was the FIRST in this world to PUBLICALLY criticize the hype or deception in iPS research (see numerous PUBLICATIONS collected in part at http://im1.biz/iPS.htm ). As a matter of FACT, the first PEER-reviewed Critical Review on iPSCs was written by me and published in Stem Cells and Dev. (17:391-397, 2008; http://www.liebertonline.com/doi/abs/10.1089/scd.2008.0062 ). This review has been downloaded over 6500 times (a number given to me a year ago) but, INTERESTINGLY, cited only a few times. More PROBLEMATICALLY, it has NOT been cited by any BIG SHOTS in the iPS research field even though many of their later “discoveries” are merely confirmations of my original discoveries. I should point out many of these BIG SHOTS have been DIRECTLY criticized by me and were given my PUBLICATIONS and invited for rebuttal but all of them failed to do that, at least in public.
      Now, why should I say that this “new” discovery confirmed essentially all of my old discoveries on iPSCs?
      First, it proved that, just I pointed out many times and my views were rejected many times by all “top” journals including Nature, iPSCs are distinct from ESCs and this distinction can be revealed in many different ways.
      Second, it supported my discovery that iPSCs are incorrectly programmed stem cells or, in other words, man-made cancer stem cells (mmCSCs).
      Thirdly, it corresponded with my charge that using severe combined immunodeficiency (SCID) animals to demonstrate the “success” of iPSC-based therapy is a severe flaw in study design or an intention for hiding some natural problems.
      Now, the so-called “ethical” and “safe” iPSCs claimed as “indistinguishable” from ESCs have been shown to be “unwanted” by even their original donors. What a “bright” future would it be for the iPSC-based cell therapy, if the patients do not want to be first sub-lethally irradiated and thus become immuno-deficient for receiving such a “regenerative” medicine?
      By the way, I congratulate the authors of this Nature paper for reaching a sound conclusion that “the abnormal expression of antigens not expressed during normal development or differentiation of ESCs [likely] leading to the break of peripheral tolerance”. However, if I was the author of this paper, I would conclude the paper with this statement: we may just realize some dark sides of the iPSCs such as their over-expression of some tumor genes. But the bright side of this negative result for iPSC therapy is that nature may not be fooled when we force it to accept some wrong programs. It is a fortune that the original life program has ability to distinct normal ESCs from abnormal iPSCs and uses its uncompromised immunity to destroy cancerous iPSCs before they can do more harm.
      With this insight in mind, when should iPS research come out of a detour?
      When should iPSCs’ real value as surrogates for natural cancer cells be utilized for searching anti-cancer drugs more effectively and efficiently?
      I hope that day will come soon and I wish to offer my invention of using iPSCs for discovering anti-cancer drugs (patent-pending) for anyone interested in improving human health.

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