1. English audio file (mp3 format, 23.6 MB)

This session incudeed several presentations that focused on different approaches that can trigger or enhace potent cellular and humoral respones . These approaches included the development of novel delivery systems such as vectors or viral particles , cytokines and also the inclusion in vaccines of molecules that can enhance immune responses . [

Dr S Kent presented a novel approach or OPAL which consists in loading peripheral blood mononuclear cells or whole blood with SIV peptides and reinfusing these cells into infected macaques to determine whether such loaded cells can trigger immune responses to the peptides . He was able to demonstrate that such loaded cells were indeed able to induce the production of cytokines after in vivo immunisation with laoded cells . This approach is safe and can be used without any prior knowledge of HLA polymorphism .  It remains to be seen whether such immune responses are protetive and whether they can allow the control of viral load .

Dr Fakruddin pesented a very interstung set of exoperiments showing that the HPV VLPs can induce the production of IL-27 by monocytes and dendritic cells leading to the control of viral replication in CD4 cells . Il-27 in a recombinant form was able to mimick such an effect and of note IL-27 production inhibited the replciation of both X4 and R5 strains .

[Major themes in the discussion, including comments from the audience, quotes and recommendations]

This session included several presentations that focused on different approaches that can trigger or enhance potent cellular and humoral responses . These approaches included the development of novel delivery systems such as vectors or viral particles , cytokines and also the inclusion in vaccines of molecules that can enhance immune responses . [

Dr S Kent presented a novel approach or OPAL which consists in loading peripheral blood mononuclear cells or whole blood with SIV peptides and reinfusing these cells into infected macaques to determine whether such loaded cells can trigger immune responses to the peptides . He was able to demonstrate that such loaded cells were indeed able to induce the production of cytokines after in vivo immunization with loaded cells . This approach is safe and can be used without any prior knowledge of HLA polymorphism .  It remains to be seen whether such immune responses are protective and whether they can allow the control of viral load .

Dr Fakruddin presented a very interesting set of experiments showing that the HPV VLPs can induce the production of IL-27 by monocytes and dendritic cells leading to the control of viral replication in CD4 cells . Il-27 in a recombinant form was able to mimic such an effect and of note IL-27 production inhibited the replication of both X4 and R5 strains .

Dr Xin generated recombinant adenoviruses between Ad5 and which included the fiber of Ad35 . These chimeric viruses were much more efficient in infecting Dendritic cells ( DCs) . In vivo they triggered in mice more potent immune responses than vaccinia vectors or Ad5 encompassing the same immunogen . They were more immunogenic in primates . Finally they were capable of inducing a more efficient control of viral replciation in macaques that had been immunized during HAART treatment and in which treatment was interrupted . 

Dr Wang explored the capacity of different ligands  of  TNF-R family members to induce the proliferation and effector and functional differentiation of CD8 T cells . She used CD70 ( CD27)  LIGHT , 4-1BBL  and showed that CD70 and 4-1BBL alone and in combination were very potent in inducing effector function of CD8 memory T cells . This offers very exciting perspectives for the development of novel adjuvants of T cells responses.

Dr Zhang presented also as very original system to induce strong cellular and humoral responses . This system relied on the expression by SHIV VLPs of CD40L ; incorporation of CD40L in these VLPs led to a much more efficient maturation of DCs as evidenced by the expression of several cell surface markers associated with mature DCs , the capacity to induce strong allogeneic responses and the increased production of cytokines such as IL-12 . More importantly these VLPs which included CD40L were very potent in inducing strong cellular and humoral responses specific for the SHIV envelope.

Altogether the talks in this session highlighted novel pathways which can boost immune responses a much needed tool in the quest for an HIV vaccine .