A novel immunodominant CD8+ T cell response restricted by a common HLA-C allele targets a conserved region of Gag HIV-1 clade CRF01_AE infected Thais.

BACKGROUND: CD8+ T cell responses play an important role in the control of HIV-1. The extensive sequence diversity of HIV-1 represents a critical hurdle to developing an effective HIV-1 vaccine, and it is likely that regional-specific vaccine strains will be required to overcome the diversity of the different HIV-1 clades distributed world-wide. Unfortunately, little is known about the CD8+ T cell responses against CRF01_AE, which is responsible for the majority of infections in Southeast Asia. METHODOLOGY/PRINCIPAL FINDINGS: To identify dominant CD8+ T cell responses recognized in HIV-1 clade CRF01_AE infected subjects we drew upon data from an immunological screen of 100 HIV-1 clade CRF01_AE infected subjects using IFN-gamma ELISpot to characterize a novel immunodominant CD8+ T cell response in HIV-1 Gag restricted by HLA-Cw*0102 (p24, (277)YSPVSILDI(285), YI9). Over 75% of Cw*0102+ve subjects targeted this epitope, representing the strongest response in more than a third of these individuals. This novel CD8 epitope was located in a highly conserved region of HIV-1 Gag known to contain immunodominant CD8 epitopes, which are restricted by HLA-B*57 and -B*27 in clade B infection. Nonetheless, viral escape in this epitope was frequently observed in Cw*0102+ve subjects, suggestive of strong selection pressure being exerted by this common CD8+ T cell response. CONCLUSIONS/SIGNIFICANCE: As HLA-Cw*0102 is frequently expressed in the Thai population (allelic frequency of 16.8%), this immunodominant Cw*0102-restricted Gag epitope may represent an attractive candidate for vaccines specific to CRF01_AE and may help facilitate further studies of immunopathogenesis in this understudied HIV-1 clade.

Effect of solid lipid nanoparticles formulation compositions on their size, zeta potential and potential for in vitro pHIS-HIV-hugag transfection.

PURPOSE: This work was conducted to determine model equations describing the effect of solid lipid nanoparticles (SLN) formulation compositions on their size and zeta potential using the face-centered central composite design and to determine the effect of SLN formulation compositions on the potential for in vitro pHIS-HIV-hugag transfection. MATERIALS AND METHODS: SLN were prepared by the hot high pressure homogenization technique using cetylpalmitate as lipid matrix at varying concentrations of Tween 80 and Span 85 mixture, dimethyldioctadecyl ammonium bromide (DDAB) and cholesterol. Size and zeta potential used as responses of the design were measured at pH 7.0. The model equations were accepted as statistical significance at p value of less than 0.05. Ability of SLN to form complex with pHIS-HIV-hugag was evaluated by electrophoretic mobility shift assay. In vitro cytotoxicity of SLN was studied in HeLa cells using alamar blue bioassay. The potential of SLN for in vitro pHIS-HIV-hugag transfection was also determined in HeLa cells by western blot technique. RESULTS: SLN possessed diameter in a range of 136-191 nm and zeta potential 11-61 mV depending on the concentrations of surfactant mixture, DDAB and cholesterol. The regression analysis showed that the model equations of responses fitted well with quadratic equations. The ability of SLN to form complex with pHIS-HIV-hugag was also affected by formulation compositions. In vitro cytotoxicity results demonstrated that HeLa cells were not well tolerant of high concentrations of SLN but still survived in a range of 100-200 microg/ml of SLN in culture medium. The results of transfection study showed ability of SLN to use as a vector for in vitro pHIS-HIV-hugag transfection. However, their potential for in vitro transfection was lower than the established transfection reagent. CONCLUSIONS: Size and zeta potential of SLN could be predicted from their quadratic model equations achieved by combination of three variables surfactant, DDAB and cholesterol concentrations. In addition, these variables also affected the potential of SLN as a vector for in vitro pHIS-HIV-hugag transfection. The results here provide the framework for further study involving the SLN formulation design for DNA delivery.