**8. Immune based therapies**

Since the discovery of HIV repeated attempts to achieve effective protection using conven‐ tional methods of immunoprophylaxis have resulted in outright failure. The failure of the preventive strategies has lead to the concept of 'immunotherapy' or 'immune based therapy'. This strategy involves in the manipulation of the immune system in a therapeutic motive to eliminate the already acquired infection, rather than preventing new infection. The immune based therapies involve in enhancing the potency of the immune system to counteract HIV by reducing inflammation, preventing immune activation by HIV-1 or promoting effective immune responses against HIV. The different modalities used to achieve this effect can be broadly classified into non-HIV antigen specific therapies and those which use the HIV antigens (Table-6)[6, 165].

None of the immune based therapies have provided satisfactory results so far. Among the available methods of immunotherapy, HIV specific CTL induction using the dendritic cells is of recent interest and appears to be a promising strategy. Recent studies reveal that a thera‐ peutic vaccine using autologous monocyte-derived dendritic cells pulsed with heat-inactivat‐ ed whole HIV, stimulated anti-HIV immune response and shifted the virus/host balance in favor of the host when administered to patients on HAART with CD4+ T-cell count >450 cells/ mm. At week 12 after ART interruption, 55% of people in the vaccinated group represented decrease of their viral load by at least 10-fold or 90%, compared with just 9% in the control group receiving non-pulsed DCs. These proportions dropped to 35% and 0%, respectively at week 24. This significant decrease in plasma viral load observed in vaccinated recipients was associated with a consistent increase in HIV-1-specific T cell responses. These data indicate that HIV-1-specific immune responses are elicited by the therapeutic DC vaccination. This could significantly reduce plasma viremia after ART interruption in HIV patients chronically infected but controlled with sufficiently high CD4 numbers. Thus, this study warrants further investigation with new candidates and/or new optimized strategies of vaccination toward the final goal to achieve a functional cure of HIV infection. Although heat-inactivated whole HIV was used as the antigen in this strategy, direct expression of the mRNA derived from patient's cells can also be considered using DCs in the immune therapy which expects highly precise antiviral efficacy targeting not only HIV but also non-viral antigens [166].
