At the fungal cell surface and may be relevant also to the interactions with other effector systems not addressed here. Nonetheless, other Fc-dependent and independent biological activities of this antibody could play a role in vivo, and these need to be evaluated in future studies. For instance, the protective mAb, through its binding to the secreted b1,3-glucan and Als3 could inhibit biofilm formation to which both this polysaccharide and the ALS3 protein seem to play a role, and thus interfere with this process which has a key role in fungal invasion. Conceivably, this antibody may also modulate, to the host��s advantage, the interactions of fungal cells with Dectin-1 and other critical receptors of innate immunity or also abrogate the inhibitory capacity expressed by some b-glucans on maturation of host dendritic cells, which are critically involved in the generation of protective anti-fungal immunity. Taken together, the data presented in this study identify blockade of adherence and interference with hyphal growth as possible mechanisms of protection by anti-b-1,3-glucan antibodies. This highlights the exciting possibility that antibodies which neutralize virulence factors of the fungus, thus not relying entirely upon host factors for their therapeutic activity, would be of value in the fight against pathogenic fungi in immuno-compromized subjects. Nonetheless, further studies are needed to address in detail the mechanisms of antibody protection in vivo. The human immunodeficiency virus type 1, like 
all other complex retroviruses, tightly regulates transcription from its genome. This regulation is mediated by both viral and cellular factors. The viral regulatory protein, Tat, stimulates transcription elongation of HIV-1 through a series of events termed Tat Benzethonium Chloride transactivation. Tat recruits the human positive transcription elongation factor b to the TAR RNA element at the 59 end of nascent transcripts. Tat interacts directly with cyclin T1, a component of PTEFb, which allows recognition of TAR. P-TEFb recruitment has been proposed to be necessary and sufficient for transcriptional elongation. The CDK9 kinase activity of P-TEFb results in hyperphosphorylation of the carboxyl-terminus domain of the largest subunit of RNA Polymerase II, leading to efficient elongation. Many groups have investigated the LOUREIRIN-B mechanism by which HIV-1 utilizes P-TEFb as a cellular cofactor for Tat transactivation.