Introduction. We previously reported that in HIV-1 infected patients circulating Vdelta1 T lymphocytes (V?1) increase and proliferate in vitro in response to Candida albicans (Ca). Herein, we analysed the effects of MF59 adjuvant on the V?1 T cell responses to hemagglutinin (HA) and Ca in HIV-1 seropositive and seronegative adults after influenzal vaccine, to clarify the molecular mechanisms triggered in vivo by an adjuvanted vac-
cine against influenza virus.
Materials and methods. 58 seropositive (HIV-1+) and 48 seronegative (HIV-1-) subjects received influenzal vaccines containing or not the MF59 adjuvant. The follow-up of in vitro T cell proliferation and cytokine production (IL-17A, IL-22, IL-23, IL-6) to HA and Ca antigens were performed at different time points
(at basal time and after 30 and 90 days from vaccination) by cytofluorimetric approaches.
Results. We confirmed that in HIV-1 infected individuals the V?1 T cell subset is expanded in HIV-1 infected individuals and moreover the number of circulating V?1 T cells significantly enhanced in all HIV-1+ subjects on day 90 after influenza vaccination. Regard the follow-up of proliferative responses, the increments of CD3+ response to HA and V?1 T cells to Ca in HIV-1+ individuals were detectable earlier on day 30 for MF59-vaccinated patients, instead on day 90 post-vaccination in HIV+-vaccinated without MF59 adjuvant. Of note, production of IL-17A and IL-22, two cytokines with anti-fungal activity, in response to Ca was enhanced (for IL-17A) or restored (for IL-22) by vaccination in HIV-1+ donors, mainly using the MF59-adjuvanted vaccine. Moreover, after vaccination IL-23 and IL-6 production increased in response to HA in the HIV+ and HIV- groups vaccinated with MF59 adjuvant.
Conclusions. We suggest that in HIV-1 infected patients the circulating V?1 T lymphocytes reactive to Ca upon challenge with influenza virus vaccine receive an activating/enhancing signal mediated by cytokines triggered by the boost with HA antigen particularly in presence of MF59 adjuvant.