Up to date, many transgenes have been successfully introduced into the plastid genome of model plant tobacco and many other important crop plants for various agronomic traits. Initially, this technology was limited to model plant species, but now it has been extended to some other important crops. Still there are many agronomically important cereals crops in which plastid engineering has not yet been standardized. Plastid transformation has been proved to result in high levels of transgene expression. It has also provided a baseline for production of proteinaceous pharmaceuticals, such as antigens, antibodies and antimicrobials in a cost effective manner. Bock [27] believes that a great progress has been achieved over years in investigating the mechanisms that govern transgene expression from the plastid genome and in using this technology for biotechnological applications. We agree with the author that "the routine use of plastid engineering in biotechnology is still a long way off, but would surely benefit the humanity in the near future". There is no doubt that plastid engineering holds a great potential in plant biotechnology; but like every new technology, there are some challenges which need to be addressed before its widespread adoption. Among other important factors to be solved are the protein purification and expression level control. Role of glutathione in immunity and inflammation in the lung Reactive oxygen species and thiol antioxidants, including glutathione (GSH), regulate innate immunity at various levels. This review outlines the redox-sensitive steps of the cellular mechanisms implicated in inflammation and host defense against infection, and describes how GSH is not only important as an antioxidant but also as a signaling molecule. There is an extensive literature of the role of GSH in immunity. Most reviews are biased by an oversimplified picture where “bad” free radicals cause all sorts of diseases and “good” antioxidants protect from them and prevent oxidative stress. While this may be the case in certain fields (eg, toxicology), the role of thiols (the topic of this review) in immunity certainly requires wearing scientist’s goggles and being prepared to accept a more complex picture. This review aims at describing the role of GSH in the lung in the context of immunity and inflammation. The first part summarizes the history and basic concepts of this picture. The second part focuses on GSH metabolism/levels in pathology, the third on the role of GSH in innate immunity and inflammation, and the fourth gives 4 examples describing the importance of GSH in the response to infections. It is now thought that oxidative stress is implicated in the pathogenesis of several diseases and conditions, from aging to inflammation and carcinogenesis, if not as a primary cause of disease at least as an aggravating mechanism.