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HIV remains a significant global burden and without an effective vaccine, it is crucial to develop microbicides to halt the initial transmission of the virus. Several microbicides have been researched with various levels of success. Amongst these, the broadly neutralising antibodies and peptide lectins are promising in that they can immediately act on the virus and have proven efficacious in in vitro and in vivo protection studies. For the purpose of development and access by the relevant population groups, it is crucial that these microbicides be produced at low cost. For the promising protein and peptide candidate molecules, it appears that current production systems are overburdened and expensive to establish and maintain. With recent developments in vector systems for protein expression coupled with downstream protein purification technologies, plants are rapidly gaining credibility as alternative production systems. Here we evaluate the advances made in host and vector system development for plant expression as well as the progress made in expressing HIV neutralising antibodies and peptide lectins using plant-based platforms., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Maize (Zea mays L.) is the most important cereal food crop in sub-Saharan Africa and Latin America, and a key feed crop in Asia, whereas pearl millet (Pennisetum glaucum (L.) R. Br.) is a staple food that supplies a major proportion of calories and protein to large segments of the populations living in the semi-arid tropical regions of Africa and Asia. The limitations of biological gene transfer with Agrobacterium tumefaciens specifically related to recalcitrant cereal crops, led to the development of alternative methods of which high-velocity microprojectiles, biolistic genetic transfer is the most successful and also the most widely employed. Agrobacterium facilitated transformation is the method of choice especially for deregulation of commercial transgenic food crop products, but biolistic-mediated transformation is still valid for proof of concept and functional genomics applications. Biolistic-mediated transformation and the production of transgenic plantlets via somatic embryogenesis of two maize strains viz. Hi-II (a laboratory strain) and M37W (a South African elite white maize genotype) as well as a pearl millet strain (842B) are described in this chapter. The stages described include: (1) proliferation of immature zygotic embryos for biolistic-mediated transformation, (2) induction and maintenance of transgenic embryogenic tissue on selection medium; (3) maturation (both morphological and physiological) of transgenic somatic embryos; and (4) germination of the somatic embryos to putative transgenic primary events. Maize and pearl millet cultures were regenerated via somatic embryogenesis as they are bipolar structures that shoot and root simultaneously. The culture media described in this chapter rarely induced or regenerated plantlets via organogenesis.