Limits...
Biocompatible anionic polymeric microspheres as priming delivery system for effetive HIV/AIDS Tat-based vaccines.

Titti F, Maggiorella MT, Ferrantelli F, Sernicola L, Bellino S, Collacchi B, Fanales Belasio E, Moretti S, Pavone Cossut MR, Belli R, Olivieri E, Farcomeni S, Compagnoni D, Michelini Z, Sabbatucci M, Sparnacci K, Tondelli L, Laus M, Cafaro A, Caputo A, Ensoli B - PLoS ONE (2014)

Bottom Line: Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat.Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity.Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

View Article: PubMed Central - PubMed

Affiliation: National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.

ABSTRACT
Here we describe a prime-boost regimen of vaccination in Macaca fascicularis that combines priming with novel anionic microspheres designed to deliver the biologically active HIV-1 Tat protein and boosting with Tat in Alum. This regimen of immunization modulated the IgG subclass profile and elicited a balanced Th1-Th2 type of humoral and cellular responses. Remarkably, following intravenous challenge with SHIV89.6Pcy243, vaccinees significantly blunted acute viremia, as compared to control monkeys, and this control was associated with significantly lower CD4+ T cell depletion rate during the acute phase of infection and higher ability to resume the CD4+ T cell counts in the post-acute and chronic phases of infection. The long lasting control of viremia was associated with the persistence of high titers anti-Tat antibodies whose profile clearly distinguished vaccinees in controllers and viremics. Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat. Finally, among vaccinees, titers of anti-Tat IgG1, IgG3 and IgG4 subclasses had a significant association with control of viremia in the acute and post-acute phases of infection. Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity. Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

Show MeSH

Related in: MedlinePlus

Epitope mapping and virological outcome.(A) Plasma anti-Tat IgG responses to single Tat peptide were determined by ELISA at week 38 after the first immunization. To map specific responses, individual 15mer peptides (overlapping by 10 aa) spanning the aa 1–90 of Tat were used. The histogram inserted within the graph represents the anti-Tat IgG titers of vaccinated monkeys at week 38. (B) In the area plot graph is reported the cumulative means of the O.D. values of vaccinees grouped according to their virological status (controllers in red and viremics in blue). The dashed line with one, two or three asterisks represents the statistical analyses (Mann-Whitney test or unpaired t-test; GrapPad InStat vers 3.05 software, San Diego, Ca, USA) performed by comparing the epitope reactivity to the indicated Tat domains of controllers versus viremic macaques. These analyses were performed either comparing the reactivities to each single peptide (aa 61–75; * p = 0,037) or to grouped peptides (aa 61–90, *** p = 0,0084 and aa 61–85, ** p = 0,014). On the top of the graph are reported the Tat aa sequence and the associated Tat functional domains. The colored aa sequence represents the region against which anti-Tat antibodies from controllers but not viremic animals are directed.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4214729&req=5

pone-0111360-g006: Epitope mapping and virological outcome.(A) Plasma anti-Tat IgG responses to single Tat peptide were determined by ELISA at week 38 after the first immunization. To map specific responses, individual 15mer peptides (overlapping by 10 aa) spanning the aa 1–90 of Tat were used. The histogram inserted within the graph represents the anti-Tat IgG titers of vaccinated monkeys at week 38. (B) In the area plot graph is reported the cumulative means of the O.D. values of vaccinees grouped according to their virological status (controllers in red and viremics in blue). The dashed line with one, two or three asterisks represents the statistical analyses (Mann-Whitney test or unpaired t-test; GrapPad InStat vers 3.05 software, San Diego, Ca, USA) performed by comparing the epitope reactivity to the indicated Tat domains of controllers versus viremic macaques. These analyses were performed either comparing the reactivities to each single peptide (aa 61–75; * p = 0,037) or to grouped peptides (aa 61–90, *** p = 0,0084 and aa 61–85, ** p = 0,014). On the top of the graph are reported the Tat aa sequence and the associated Tat functional domains. The colored aa sequence represents the region against which anti-Tat antibodies from controllers but not viremic animals are directed.

Mentions: As described above, vaccinated monkeys were grouped in controllers and viremics according to the patterns of viral replication dynamics in the chronic phase of the infection (Table 1). Of interest, controllers had persistently measurable anti-Tat antibodies in the post-acute and chronic infection, whereas viremics did not. When also the CD4 T cell counts were considered, it became apparent that controllers exhibited during the chronic phase of the infection a significant reduction of viral loads (p<0.0001), high and durable anti-Tat IgG antibody titers (p<0.0001) and CD4+ T cell counts (p = 0.0004), as compared to viremics (Table 1), suggesting a role for anti Tat antibody responses in the observed control of viral replication in vaccinees. To gain further insights, we analyzed the epitope specificity of IgG antibodies after the last Tat/Alum boost (week 38). In this respect, all vaccinated macaques showed reactivity directed in particular against peptides encompassing the Tat N-terminus (aa 1–20). The next most recognized domains was aa 46–60 (7 out of 9 monkeys), followed by the regions encompassed by aa 51–65, aa 61–75 and aa 71–85, which were recognized by the plasma of 6 out of 9 monkeys, while the aa 76–90 domain was recognized by 5 vaccinees (Fig. 6A). Only a minority of vaccinees had detectable antibodies against the remaining Tat domains: 4 monkeys reacted with aa 36–55, whereas only 3 macaques reacted with the aa 56–70 or aa 66–80 domain (Fig. 6A). As the anti-Tat IgG titers were similar in all monkeys (range 1∶1,600/12,600), the observed epitope specificity conceivably reflects qualitatively different responses (Fig. 6A) in vaccinated animals experiencing different challenge outcome. For instance, monkey BD765B (vaccinated and viremic), in spite of having anti-Tat IgG titers 1∶12,600, did not show reactivity to the Tat peptides encompassing aa 61–85. In contrast, the AH484 (vaccinated and controller), which exhibited a lower anti-Tat Ab response, did react to the 61–85 Tat peptides (OD range 2.9–3.1).


Biocompatible anionic polymeric microspheres as priming delivery system for effetive HIV/AIDS Tat-based vaccines.

Titti F, Maggiorella MT, Ferrantelli F, Sernicola L, Bellino S, Collacchi B, Fanales Belasio E, Moretti S, Pavone Cossut MR, Belli R, Olivieri E, Farcomeni S, Compagnoni D, Michelini Z, Sabbatucci M, Sparnacci K, Tondelli L, Laus M, Cafaro A, Caputo A, Ensoli B - PLoS ONE (2014)

Epitope mapping and virological outcome.(A) Plasma anti-Tat IgG responses to single Tat peptide were determined by ELISA at week 38 after the first immunization. To map specific responses, individual 15mer peptides (overlapping by 10 aa) spanning the aa 1–90 of Tat were used. The histogram inserted within the graph represents the anti-Tat IgG titers of vaccinated monkeys at week 38. (B) In the area plot graph is reported the cumulative means of the O.D. values of vaccinees grouped according to their virological status (controllers in red and viremics in blue). The dashed line with one, two or three asterisks represents the statistical analyses (Mann-Whitney test or unpaired t-test; GrapPad InStat vers 3.05 software, San Diego, Ca, USA) performed by comparing the epitope reactivity to the indicated Tat domains of controllers versus viremic macaques. These analyses were performed either comparing the reactivities to each single peptide (aa 61–75; * p = 0,037) or to grouped peptides (aa 61–90, *** p = 0,0084 and aa 61–85, ** p = 0,014). On the top of the graph are reported the Tat aa sequence and the associated Tat functional domains. The colored aa sequence represents the region against which anti-Tat antibodies from controllers but not viremic animals are directed.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214729&req=5

pone-0111360-g006: Epitope mapping and virological outcome.(A) Plasma anti-Tat IgG responses to single Tat peptide were determined by ELISA at week 38 after the first immunization. To map specific responses, individual 15mer peptides (overlapping by 10 aa) spanning the aa 1–90 of Tat were used. The histogram inserted within the graph represents the anti-Tat IgG titers of vaccinated monkeys at week 38. (B) In the area plot graph is reported the cumulative means of the O.D. values of vaccinees grouped according to their virological status (controllers in red and viremics in blue). The dashed line with one, two or three asterisks represents the statistical analyses (Mann-Whitney test or unpaired t-test; GrapPad InStat vers 3.05 software, San Diego, Ca, USA) performed by comparing the epitope reactivity to the indicated Tat domains of controllers versus viremic macaques. These analyses were performed either comparing the reactivities to each single peptide (aa 61–75; * p = 0,037) or to grouped peptides (aa 61–90, *** p = 0,0084 and aa 61–85, ** p = 0,014). On the top of the graph are reported the Tat aa sequence and the associated Tat functional domains. The colored aa sequence represents the region against which anti-Tat antibodies from controllers but not viremic animals are directed.
Mentions: As described above, vaccinated monkeys were grouped in controllers and viremics according to the patterns of viral replication dynamics in the chronic phase of the infection (Table 1). Of interest, controllers had persistently measurable anti-Tat antibodies in the post-acute and chronic infection, whereas viremics did not. When also the CD4 T cell counts were considered, it became apparent that controllers exhibited during the chronic phase of the infection a significant reduction of viral loads (p<0.0001), high and durable anti-Tat IgG antibody titers (p<0.0001) and CD4+ T cell counts (p = 0.0004), as compared to viremics (Table 1), suggesting a role for anti Tat antibody responses in the observed control of viral replication in vaccinees. To gain further insights, we analyzed the epitope specificity of IgG antibodies after the last Tat/Alum boost (week 38). In this respect, all vaccinated macaques showed reactivity directed in particular against peptides encompassing the Tat N-terminus (aa 1–20). The next most recognized domains was aa 46–60 (7 out of 9 monkeys), followed by the regions encompassed by aa 51–65, aa 61–75 and aa 71–85, which were recognized by the plasma of 6 out of 9 monkeys, while the aa 76–90 domain was recognized by 5 vaccinees (Fig. 6A). Only a minority of vaccinees had detectable antibodies against the remaining Tat domains: 4 monkeys reacted with aa 36–55, whereas only 3 macaques reacted with the aa 56–70 or aa 66–80 domain (Fig. 6A). As the anti-Tat IgG titers were similar in all monkeys (range 1∶1,600/12,600), the observed epitope specificity conceivably reflects qualitatively different responses (Fig. 6A) in vaccinated animals experiencing different challenge outcome. For instance, monkey BD765B (vaccinated and viremic), in spite of having anti-Tat IgG titers 1∶12,600, did not show reactivity to the Tat peptides encompassing aa 61–85. In contrast, the AH484 (vaccinated and controller), which exhibited a lower anti-Tat Ab response, did react to the 61–85 Tat peptides (OD range 2.9–3.1).

Bottom Line: Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat.Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity.Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

View Article: PubMed Central - PubMed

Affiliation: National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.

ABSTRACT
Here we describe a prime-boost regimen of vaccination in Macaca fascicularis that combines priming with novel anionic microspheres designed to deliver the biologically active HIV-1 Tat protein and boosting with Tat in Alum. This regimen of immunization modulated the IgG subclass profile and elicited a balanced Th1-Th2 type of humoral and cellular responses. Remarkably, following intravenous challenge with SHIV89.6Pcy243, vaccinees significantly blunted acute viremia, as compared to control monkeys, and this control was associated with significantly lower CD4+ T cell depletion rate during the acute phase of infection and higher ability to resume the CD4+ T cell counts in the post-acute and chronic phases of infection. The long lasting control of viremia was associated with the persistence of high titers anti-Tat antibodies whose profile clearly distinguished vaccinees in controllers and viremics. Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat. Finally, among vaccinees, titers of anti-Tat IgG1, IgG3 and IgG4 subclasses had a significant association with control of viremia in the acute and post-acute phases of infection. Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity. Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

Show MeSH
Related in: MedlinePlus