2010年7月28日水曜日

パッチワクチン

動物実験でパッチによるワクチン接種の確認ができたようだ。
 微小な針が多数ついたパッチを皮膚にはるだけで接種できるインフル
ワクチンを、米ジョージア工科大などの研究チームが開発し、動物実験で
効果を確認した。

パッチは、生体に吸収されやすい物質でできた高さ0.7mmの針が100本。
針の中に、液体ワクチンを凍結乾燥させた粉末が封入。
豚の皮膚を使った実験で、親指でパッチを皮膚に押しつけただけで表皮に
刺さり、数分以内に溶け、ワクチンと針が皮膚に吸収されることを確認。
マウス6匹にインフルウイルスを感染させたところ、すべて生き残り、体重も
5%以下しか減らなかった。
実用化すれば、自分でも接種でき、輸送や保存も簡便になり、接種費用が
抑えられる。

ワクチンの種類が書いていないし、詳細は不明。
過去に注射針で奇形が生じたこともあり、皮膚近くであれば、問題は少ない
かもしれないが、実際にはワクチンの成分の方が問題になるのだろう。

動物細胞でワクチン開発


US scientists invent new vaccine patch Al Jazeera


---パッチはるだけでインフルワクチン接種 米研究チーム---
2010年7月20日1時0分
http://www.asahi.com/science/update/0719/TKY201007190310.html

 微小な針が多数ついたパッチを皮膚にはるだけで接種できるインフルエンザワクチンを、米ジョージア工科大などの研究チームが開発し、動物実験で効果を確認した。針は皮膚に刺さると溶け、ワクチンと共に吸収される。実用化すれば、自分でも接種でき、輸送や保存も簡便になり、接種費用が抑えられる。米医学誌ネイチャー・メディシン(電子版)で発表した。
 開発したパッチは、生体に吸収されやすい物質でできた高さ0.7ミリの針が100本ついている。針の中に、液体ワクチンを凍結乾燥させた粉末が入っている。
 人の皮膚に似た豚の皮膚を使った実験で、親指でパッチを皮膚に押しつけただけで表皮に刺さり、数分以内に溶け、ワクチンと針が皮膚に吸収されることを確認した。深く刺さらないため、研究チームは「痛くはないはずだ」としている。
 このワクチンを接種したマウス6匹にインフルウイルスを感染させたところ、すべて生き残り、体重も5%以下しか減らなかった。通常のワクチンを注射したマウスも同様だったが、接種しないマウスは6日以内にすべて死んだ。
 研究チームは「通常のワクチンと同等の効果がある。製造費用も同程度だが、接種に医師や看護師が必要なく、注射針の処理もいらず、費用は安くなる」とみている。(大岩ゆり)


---Dissolving Vaccine Patch Might Eliminate Flu Shots---
20 July 2010
Jessica Berman
http://www1.voanews.com/english/news/health/Dissolving-Vaccine-Patch-Might-Eliminate-Flu-Shots-98867364.html

Researchers have developed a skin patch that could painlessly deliver vaccines through the skin, replacing hypodermic needles. Scientists say the invention could simplify flu immunization programs by allowing patients to administer vaccines themselves.

Unlike a hypodermic needle that injects a vaccine into muscle tissue, the patch contains microscopic needles that painlessly deliver a vaccine into the outer layer of the skin within minutes after being applied. "It takes about 10 minutes for the microneedles to fully dissolve and to release the vaccine," said Mark Prausnitz, a chemical and biomedical engineer at Georgia Institute of Technology in Atlanta, who led a study of the microneedle patch in mice.

Researchers developed a prototype of the vaccine delivery system, a .65 millimeter patch with an array of 100 microneedles carrying a single dose of an influenza vaccine, which they applied to the skin of mice. A second group of mice received the same flu vaccine through a conventional hypodermic needle injection.

A month later, both groups were exposed to the influenza virus. Investigators found that the vaccine patch offered as much protection against the flu as the vaccine administered by injection.

Prausnitz says that there is evidence that the microneedle patch offers better protection against the flu than injected immunizations.

In a different group of animals, researchers found that after three months, the mice that wore the vaccine patch cleared the virus from their lungs more effectively than those that received a shot.

Prausnitz says that there is a reason why inoculation through the skin might be more effective than vaccination by injection. "The body's immune system has sentry cells that exist throughout the body looking for foreign things that have come to the body that require an immune response. The cells that are in the skin are different kinds of cells than ones that are in the muscle. So it is reasonable to expect that the immune response would be different when the vaccine is given to different tissues. We found that it is not only different, but it is better," he said.

Prausnitz says that after the patch is used, it can be thrown away because all of the microscopic needles dissolve quickly into the fluids in the skin and what remains is only the water-soluble backing.

The researchers are now working on a microneedle patch that can deliver other immunization drugs within a minute or two of being applied to the skin.

In many parts of the world, Prausnitz says, there are not enough hypodermic needles to go around, so needles frequently are reused. That increases the risk of spreading the AIDS virus and other diseases such as hepatitis B. He says there would be no such problem with single-use skin patches.

Prausnitz adds that vaccination campaigns would likely be less costly, particularly in countries where there are few clinics and medical personnel to administer the programs. He says people could simply get the patches at drug dispensaries or through the mail and then apply them to their own skin.

The Georgia Institute of Technology researchers are seeking funds to conduct clinical trials as soon as possible.

A study describing the microneedle technology is published in the journal Nature Medicine.

0 コメント: