One series of projects in the group aim to facilitate the development of vaccination strategies capable of eliciting HIV-1 bNAbs via induction of CD4 T cell responses that provide optimal help for the development of appropriate B cell responses. The relationship between the nature and specificity of the CD4 T cell response and development of bNAbs targeting particular viral epitopes in HIV-infected individuals is being explored; and the relative ability of different vaccination platforms to elicit CD4 T follicular helper cell responses is being determined.
Innate responses can be activated very rapidly in response to pathogen exposure or infection, and play important roles both in containment of early pathogen replication and promotion of induction of the adaptive response. In acute HIV infection, innate immune responses may also mediate immunopathological effects by driving immune activation and facilitating virus replication and spread. We thus hypothesise that the nature of the innate response in acute HIV-1 infection may be among the factors involved in determining the prognostically important setpoint viral load; and that aspects of .innate responses may contribute to the resistance exhibited by certain individuals to full, seropositive HIV infection despite repeated viral exposure. A key implication of this is that modulation of innate responses could represent a novel approach to complement existing HIV vaccine strategies. A second series of projects in the group are addressing these hypotheses. We are also carrying out some comparative analysis of innate responses in the acute phase of other virus infections including hepatitis B and C virus infections and herpesvirus infections.
T cell responses play a key role in the elimination of many established virus infections, and multiple lines of evidence suggest that virus-specific CD8+ T cells make an important contribution to both the initial containment of primary viraemia and subsequent control of ongoing viral replication during HIV infection. Prophylactic and therapeutic strategies to combat HIV infection are thus also being designed to invoke this arm of the immune response. However the primary HIV-specific CD8 T cell response remains relatively poorly characterised, and how aspects of this response and its subsequent maintenance or evolution may impact on the initial and longer-term efficiency of control of virus replication are not well understood. A third series of projects within the group are analysing the relationship between qualitative aspects of the virus-specific CD8+ T cell response induced in primary HIV infection, the extent and kinetics of viral mutational escape from CD8+ T cell control, the fitness of the founder virus and its reduction as a consequence of acquisition of T cell escape mutations, and the subsequent efficiency of control of viral replication.