Intracerebroventricular administration of TNF-like weak inducer of apoptosis induces depression-like behavior and cognitive dysfunction in non-autoimmune mice.

Fn14, the sole known signaling receptor for the TNF family member TWEAK, is inducibly expressed in the central nervous system (CNS) in endothelial cells, astrocytes, microglia, and neurons. There is increasing recognition of the importance of the TWEAK/Fn14 pathway in autoimmune neurologic conditions, including experimental autoimmune encephalomyelitis and neuropsychiatric lupus. Previously, we had found that Fn14 knockout lupus-prone MRL/lpr mice display significantly attenuated neuropsychiatric manifestations. To investigate whether this improvement in disease is secondary to inhibition of TWEAK/Fn14 signaling within the CNS or the periphery, and determine whether TWEAK-mediated neuropsychiatric effects are strain dependent, we performed intracerebroventricular (ICV) injection of Fc-TWEAK or an isotype matched control protein to C57Bl6/J non-autoimmune mice. We found that Fc-TWEAK injected C57Bl6/J mice developed significant depression-like behavior and cognitive dysfunction. Inflammatory mediators associated with lupus brain disease, including CCL2, C3, and iNOS, were significantly elevated in the brains of Fc-TWEAK treated mice. Furthermore, Fc-TWEAK directly increased blood brain barrier (BBB) permeability, as demonstrated by increased IgG deposition in the brain and reduced aquaporin-4 expression. Finally, Fc-TWEAK increased apoptotic cell death in the cortex and hippocampus. In conclusion, TWEAK can contribute to lupus-associated neurobehavioral deficits including depression and cognitive dysfunction by acting within the CNS to enhance production of inflammatory mediators, promote disruption of the BBB, and induce apoptosis in resident brain cells. Our study provides further support that the TWEAK/Fn14 signaling pathway may be a potential therapeutic target for inflammatory diseases involving the CNS.

Tumor necrosis factor reduces the amplitude of rat cortical spreading depression in vivo.

OBJECTIVE: Brain damage and ischemia often trigger cortical spreading depression (CSD), which aggravates brain damage. The proinflammatory cytokine tumor necrosis factor (TNF) is significantly upregulated during brain damage, but it is unknown whether TNF influences spreading depression in cerebral cortex in vivo. This question is important because TNF not only furthers inflammatory reactions but might also be neuroprotective. Here we tested the hypothesis that TNF affects CSD, and we explored the direction in which CSD is modified by TNF. METHODS: CSD, elicited by pressure microinjection of KCl, was recorded in anesthetized rats and mice. TNF was administered locally into a trough, providing local TNF treatment of a cortical area. For further analysis, antibodies to TNF receptor (TNFR) 1 or 2 were applied, or CSD was monitored in TNFR1 and TNFR2 knockout mice. γ-Aminobutyric acid (GABA)A receptors were blocked by bicuculline. Immunohistochemistry localized the cortical expression of TNFR1 and TNFR2. RESULTS: Local application of TNF to the cortex reduced dose-dependently the amplitude of CSD. This effect was prevented by blockade or knockout of TNFR2 but not by blockade or knockout of TNFR1. TNFR2 was localized at cortical neurons including parvalbumin-positive inhibitory interneurons, and blockade of GABAA receptors by bicuculline prevented the reduction of CSD amplitudes by TNF. INTERPRETATION: We identified a functional link between TNF and CSD. TNF activates TNFR2 in cortical inhibitory interneurons. The resulting release of GABA reduces CSD amplitudes. In this manner, TNF might be neuroprotective in pathological conditions.

A disease- and phosphorylation-related nonmechanical function for keratin 8.

Keratin 8 (K8) variants predispose to human liver injury via poorly understood mechanisms. We generated transgenic mice that overexpress the human disease-associated K8 Gly61-to-Cys (G61C) variant and showed that G61C predisposes to liver injury and apoptosis and dramatically inhibits K8 phosphorylation at serine 73 (S73) via stress-activated kinases. This led us to generate mice that overexpress K8 S73-to-Ala (S73A), which mimicked the susceptibility of K8 G61C mice to injury, thereby providing a molecular link between K8 phosphorylation and disease-associated mutation. Upon apoptotic stimulation, G61C and S73A hepatocytes have persistent and increased nonkeratin proapoptotic substrate phosphorylation by stress-activated kinases, compared with wild-type hepatocytes, in association with an inability to phosphorylate K8 S73. Our findings provide the first direct link between patient-related human keratin variants and liver disease predisposition. The highly abundant cytoskeletal protein K8, and possibly other keratins with the conserved S73-containing phosphoepitope, can protect tissue from injury by serving as a phosphate "sponge" for stress-activated kinases and thereby provide a novel nonmechanical function for intermediate filament proteins.

CTRP3 is Significantly Decreased in Patients with Primary Hyperparathyroidism and Closely Related with Osteoporosis.

BACKGROUND: Adipokines derived from adipocytes are one of the important factors that act as circulating regulators of bone metabolism. Complement C1q/tumor necrosis factor-related protein-3 (CTRP3), a paralog of adiponectin, is are member of the CTRP superfamily. The aim of this study was to investigate the role of serum CTRP3 in the development of osteoporosis in patients with primary hyperparathyroidism. METHODS: This study included 53 patients with diagnosed primary hyperparathyroidism and 30 healthy controls. Laboratory tests for the diagnosis of primary hyperparathyroidism and serum levels of CTRP3 measured for all patients. Bone mineral density was obtained on lumbar spine 1 and 4 by dual energy X-ray absorptiometry. RESULTS: Serum CTRP3 levels were lower in patients with primary hyperparathyroidism than in the control group (p<0.001). In addition, primary hyperparathyroidism patients are were divided into two groups as, with and without osteoporosis; the levels of CTRP3 were lower in patients with osteoporosis than in patients without osteoporosis (p=0.004). In logistic regression analysis, only CTRP3 levels independently determined the patients to be osteoporosis (p<0.05). According to this analysis, decreased CTRP3 (per 1 ng/mL) levels were found to increase the risk of patients for osteoporosis by 6.9%. When the CTRP3 cut-off values were taken as 30 ng/mL, it determined osteoporosis with 76.4% sensitivity and 73.2% specificity. CTRP3 and urine calcium levels were independently associated with T score in dual energy X-ray absorptiometry. CONCLUSIONS: CTRP3 levels were significantly decreased in patients with primary hyperparathyroidism, and it is also related to osteoporosis.

Construction and preclinical characterization of Fc-mGITRL for the immunotherapy of cancer.

PURPOSE: To provide proper costimulation required for effective cancer T-cell immunity, Fc-GITRL fusion proteins were generated for use in immunotherapy protocols. EXPERIMENTAL DESIGN: Soluble fusion proteins consisting of the Fc fragment of immunoglobulin and the murine glucocorticoid-induced tumor necrosis factor-related receptor ligand (mGITRL) connected with different linkers were genetically engineered and tested for their potency in two BALB/c solid tumor models. RESULTS: In vivo, construct #178-14 (-5aa, -linker) showed the best activity (>90% tumor reduction) at doses ranging from 5 to 25 microg and was found to be intact by gel electrophoresis. Similar doses used with construct #175-2 (-linker) produced good but not as high tumor regression. Construct #5-1 (+linker), which was found to be relatively unstable by SDS gel electrophoresis, produced <60% tumor regression and required a higher dose (100 microg) to produce optimal results. Survival curves showed that Fc-mGITRL treatment extended the life of 80% of tumor-bearing mice to >3 months compared with controls that died by day 40. T-cell depletion studies showed that CD8(+) T cells play a major role in Fc-mGITRL immunotherapy, and tumors removed from Fc-mGITRL- and DTA-1-treated mice showed a significant influx of granzyme B(+) lymphocytes compared with controls. Finally, T regulatory (Treg) cell assays showed that, unlike other Fc fusion proteins, all three Fc-mGITRL constructs profoundly suppressed Treg activity. CONCLUSIONS: These studies suggest that a stable, intact Fc-mGITRL fusion protein can provide missing costimulation for the immunotherapy of solid tumors. In addition, Fc-mGITRL may alter Treg activity to enhance its effectiveness for tumor immunotherapy.

Intratumoral administration of IL2- and TNF-based fusion proteins cures cancer without establishing protective immunity.

AIM: The combination of tumor-targeting IL2- and TNF-based antibody-cytokine fusions has exhibited encouraging results in mouse and men. Here, we studied their combination to assess efficacy and mechanism of action in four different immunocompetent mouse models of cancer. METHODS: Mice receiving a single intratumoral injection of F8-IL2, F8-TNF or the combination were investigated for tumor-infiltrating leukocytes and rechallenged when cured. RESULTS: In three models, a proportion of treated animals could be cured, most probably by infiltrating NK and CD8+ T cells. Most of the cured mice did not acquire protective immunity when rechallenged with the same tumor cell line. CONCLUSION: Immunocompetent mouse tumor models may not be adequate enough to predict the search for more efficacious therapy regimens.

The Proinflammatory Cytokine GITRL Contributes to TRAIL-mediated Neurotoxicity in the HCN-2 Human Neuronal Cell Line.

BACKGROUND: Cytokines belonging to the TNF superfamily play a relevant role in neurodegenerative processes. Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL), released during neuronal injury, has proven to potently mediate and sustain neurotoxic processes leading to neuronal death. Similarly to TRAIL, the cytokine Glucocorticoid-induced TNF receptor ligand (GITRL) is able to transduce proapoptotic signals. In spite of the array of reports suggesting relationships between TRAIL and other cytokines, scanty data are, so far, available about a GITRL/TRAIL crosstalk. METHODS: Here, we investigated possible interactions between TRAIL and the GITRL system in an in vitro model of neurodegeneration, using the human cortical neuronal cell line HCN-2. Cultured HCN-2 neurons were incubated at different times with GITRL and/or TRAIL, and thereafter nucleic acid and protein expression were measured. Real-time PCR analysis showed that the human cortical neuronal cell line HCN-2 does not express GITRL mRNA, but the latter is induced after treatment with TRAIL. In addition, HCN-2 cells did not express the GITRL receptor GITR mRNA, neither in control cultures, nor after treatment with TRAIL. All mRNA data were confirmed by western blot analysis of proteins. Cell viability assay showed that TRAIL, when associated to GITRL, was able to exert additive toxic effects. A counterproof was provided in experiments performed blocking GITRL, in which TRAIL-mediated toxicity appeared significantly reduced. Results suggest that GITRL/TRAIL redundancy during neurodegenerative processes implies extended potentiation of detrimental effects of both cytokines on neurons, eventually leading to larger cell damage and death. CONCLUSION: Finally, characterization of novel molecular targets within the TRAIL/GITRL interplay may represent a platform for innovative therapy of neurodegenerative disorders.

[Atorvastatin inhibits the atherosclerotic lesion induced by tumor necrosis factor-like weak inducer of apoptosis in apolipoprotein E deficient mice]. / La atorvastatina inhibe la progresión de la lesión aterosclerótica inducida por el factor inductor débil de apoptosis similar al factor de necrosis tumoral en ratones deficientes en apolipoproteína E.

AIM: Interaction of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) with its receptor Fn14 accelerates atherosclerotic plaque development in ApoE deficient mice (ApoE KO). In this work, an analysis has been made on the effect of an HMG-CoA reductase inhibitor, atorvastatin, on atherosclerotic plaque development accelerated by TWEAK in ApoE KO mice. MATERIALS AND METHODS: Eight week-old ApoE KO mice were fed with a high cholesterol diet for 4 weeks. The animals were then randomized into 3 groups: mice injected i.p. with saline, recombinant TWEAK (10 µg/kg/twice a week), or recombinant TWEAK plus atorvastatin (1 mg/kg/day) for 4 weeks. The lesion size, cellular composition, lipid and collagen content were analyzed, as well as inflammatory response in atherosclerotic plaques present in aortic root of mice. RESULTS: TWEAK treated mice showed an increase in atherosclerotic plaque size, as well as in collagen/lipid ratio compared with control mice. In addition, macrophage content, MCP-1 and RANTES expression, and NF-κB activation were augmented in atherosclerotic plaques present in aortic root of TWEAK treated mice compared with control mice. Treatment with atorvastatin prevented all these changes induced by TWEAK in atherosclerotic lesions. Atorvastatin treatment also decreased Fn14 expression in the atherosclerotic plaques of ApoE KO mice. CONCLUSIONS: Atorvastatin prevents the pro-atherogenic effects induced by TWEAK in ApoE KO mice, which could be related to the inhibition of Fn14 expression. The results of this study provide new information on the beneficial effects of statin treatment in cardiovascular diseases.

Regression of established AB1 murine mesothelioma induced by peritumoral injections of CpG oligodeoxynucleotide either alone or in combination with poly(I:C) and CD40 ligand plasmid DNA.

INTRODUCTION: Stimulation of the CD40 receptor using an agonistic anti-CD40 antibody can slow the growth of AB1 tumors. Stimulation of the GITR receptor may also have antitumor activity by countering the immunosuppressive effects of regulatory CD4 T cells. Similarly, agonists for Toll-Like Receptors (TLR) such as CpG oligodeoxynucleotides (TLR9 agonist) have activity against AB1 tumors. Combinations of CpG with CD40 ligand and polyinosinic-polycytidylic acid (poly(I:C), TLR3 agonist) may be even stronger than CpG alone. The synergistic effects of these combinations have been tested in other tumor types but not in mesothelioma. METHODS: Established AB1 mesothelioma tumors were injected with either plasmid DNA encoding a novel 4-trimer form of murine CD40 ligand (pSP-D-CD40L), GITR ligand (GITRL), or control plasmid DNA. In addition, CpG with or without poly(I:C) was also injected intratumorally. RESULTS: Plasmid injections of pSP-D-CD40L or pSP-D-GITRL, had no significant antitumor effect, possibly reflecting the difficulty of administering DNA injections into this very dense tissue. However, the injection of CpG with or without poly(I:C) strongly suppressed tumor growth and led to long-term tumor-free survival. The response to a triple combination of pSP-D-CD40L + CpG + poly(I:C) was demonstrated by an increase in intratumoral CD8 T cells and a dramatic increase in F4/80 macrophages. CONCLUSIONS: Intratumoral injections of plasmid DNAs encoding highly active forms of either CD40 ligand or GITR ligand had no significant antitumor effects in this model, although improved DNA delivery techniques could possibly improve this strategy. In contrast, intratumoral CpG injections had significant antitumor effects and there were indications that CpG plus poly(I:C) was even more effective. Taken together, these data confirm previous reports that immune stimulants, especially CpG TLR9 agonists, have potential as a treatment for mesothelioma.

Co-immunization of mice with a retroviral DNA vaccine and GITRL-encoding plasmid augments vaccine-induced protection against retrovirus infection.

After more than 30 years of research a HIV vaccine is still not at hand. DNA vectors expressing viral antigens are very safe vaccines, but so far they have not been efficient enough to induced broad protective immunity against retroviruses. One strategy to enhance the efficiency of DNA vaccines is to augment effector T-cell priming against viral components by manipulating regulatory T-cell functions (Treg). Glucocorticoid-induced tumor necrosis factor receptor (GITR) is a molecule that is constitutively expressed on CD4(+) Treg cells, and antibodies or natural ligands binding this molecule can impair Treg cell suppression. Here we demonstrate using the retroviral Friend virus (FV) mouse model, that co-immunization of FV antigens along with GITR-ligand (GITRL) encoding plasmids protected mice efficiently against a FV challenge. On the other hand, treatment of DNA-vaccinated mice with alpha-GITR antibody did not improve vaccine-induced protection at all. Thus, for an effective priming of immunity against FV, GITRL and viral antigens might have to be expressed within the same local environment. The data suggest that limitations in DNA vaccination can be overcome by co-expressing co-stimulatory molecules that potentially manipulate the function of Treg cells during priming of anti-retroviral immunity.

Towards the development of tumor necrosis factor (TNF) sensitizers: making TNF work against cancer.

Although TNF antitumor activity has been demonstrated in many preclinical models and in non-comparative clinical trials, no evidence exists that TNF-based treatments increase patient survival. Moreover, due to systemic toxicity, TNF can only be administered through sophisticated locoregional drug-delivery systems in patients with some types of organ-confined solid tumors; as a corollary, the impossibility to administer TNF through the systemic route does not allow to test the effectiveness of this cytokine in other clinical settings for the treatment of a broader spectrum of tumor types. A challenge many researchers are tackling is to dissect the cascade of molecular events underlying tumor sensitivity to TNF so to fully explore the anticancer potential of this molecule. The rationale for the development of strategies aimed at sensitizing malignant cells to TNF is to exploit tumor-specific molecular derangements to modulate TNF biological activities and ultimately maximize its tumor-selective cytotoxicity. This would not only enhance the anticancer activity of current TNF-based locoregional regimens, but would also open the avenue to the systemic administration of this cytokine and thus to a much wider clinical experimentation of TNF in the oncology field. In this review we first summarize the molecular biology of TNF and its cancer-related properties; then, the available findings regarding some among the most promising and best characterized TNF sensitizers are overviewed.

Eficacia de adalimumab en pacientes con enfermedad de Crohn y fracaso previo a la terapia con infliximab: resultados de una serie clínica / Efficacy of adalimumab in patients with Crohn's disease and failure to infliximab therapy: a clinical series

Introducción: adalimumab, un anti-TNF humano, ha demostrado ser efectivo en la inducción y tratamiento de mantenimiento de la enfermedad de Crohn moderada-grave. Existe menos experiencia, pero este fármaco parece también eficaz en los pacientes con pérdida de respuesta o intolerancia al infliximab. Objetivo: evaluar la eficacia de adalimumab durante un año, en nuestra serie de pacientes con enfermedad de Crohn (EC) y fracaso en el tratamiento previo con infliximab. Métodos: se incluyen 25 pacientes con enfermedad de Crohn y fracaso previo a la terapia con infliximab, que son tratados con adalimumab. Se utilizaron dosis de inducción de 160/80 mg en 24 pacientes y dosis de 80/40 en un paciente. Analizamos la respuesta clínica al tratamiento con adalimumab mediante el Índice de actividad de la enfermedad de Crohn (CDAI) y las concentraciones plasmáticas de proteína C reactiva (PCR), el cese de la corticoterapia y el cierre completo de las fistulas en la semana 48. Resultados: dieciocho de veinticinco pacientes (72%) alcanzan la remisión clínica (CDAI < 150) en la semana 24 y 15/25 pacientes (60%) en la semana 48. Esto se acompañó de un descenso de los niveles de PCR de 21 a 8 mg/l en la semana 48. En nueve de quince pacientes (60%) que tomaban corticoides, se consiguió su retirada. Tres de once pacientes (27%) con enfermedad fistulosa presentaron un cierre completo de las fístulas tras el tratamiento con adalimumab. Un 72% de los pacientes (18/25) necesitaron, a lo largo del seguimiento, acortar el intervalo de tratamiento a una semana para mantener la respuesta. Cinco de veinticinco pacientes (20%) presentan efectos secundarios y en 2 de ellos (8%) fue precisa la retirada del fármaco (meningitis tuberculosa y absceso abdominal). Conclusiones: el tratamiento con adalimumab proporciona una mejoría clínica y analítica en un número significativo de pacientes con EC y fracaso previo a la terapia con infliximab(AU)

Background: adalimumab, a human anti-TNF, is an effective induction and maintenance therapy for patients with moderate to severe Crohn’s disease. It seems to be effective in patients with resistance to infliximab, too, though the experience is more limited. Aim: to evaluate the efficacy of adalimumab, in patients with Crohn’s disease (CD) and failure to previous treatment with infli - ximab. Methods: twenty-five patients with CD and failure to previous treatment with infliximab were enrolled; they were treated with 160/80 (24 patients) and 80/40 (1 patient) induction doses. We analyze clinical response to treatment with adalimumab by the Crohn’s disease Activity Index (CDAI) and plasma concentration of C-reactive protein (CRP), steroid sparing and complete fistula closure at week 48. Results: eighteen out of twenty-five patients (72%) achieved clinical remission (CDAI score < 150) at week 24 and 15/25 (60%) patients at week 48. There was a statistically significant difference (p < 0.01) in CRP serum levels from 21 to 8 mg/dl at week 48. Nine out of fifteen patients (60%) treated with corticosteroids were able to discontinue steroids. Three out of eleven patients (27%) with fistulizing Crohn’s disease had complete fistula closure after the treatment. Seventy two percent of the patients (18/25) needed to increase adalimumab to weekly dose, in order to maintain clinical response. Five out of twenty-five patients (20%) had adverse events; two of them (8%) with serious adverse events (tuberculous meningitis and abdominal abscess) that forced the withdrawal of treatment. Conclusions: according to these data, adalimumab provides a clinical and analytical improvement in patients with CD and failure to previous therapy with infliximab(AU)

CTLA-4.FasL inhibits allogeneic responses in vivo.

CTLA-4.Fas ligand (CTLA-4.FasL), a paradigmatic 'trans signal converter protein (TSCP)', can attach to APC (via CTLA-4 binding to B7) and direct intercellular inhibitory signals to responding T cells (via FasL binding to Fas receptor), converting an activating APC-to-T cell signal into an inhibitory one. Our previous studies established that CTLA-4.FasL inhibits human primary mixed lymphocyte reactions (MLR) and induces alloantigen-specific hyporesponsiveness ex vivo. The present study extends this to an in vivo context. Using splenocytes from MHC-mismatched C57BL/6 and Balb/c mice, we demonstrated that his(6)CTLA-4.FasL, effectively inhibits murine MLR. Moving in vivo, we demonstrated that subcutaneously administered his(6)CTLA-4.FasL modulates the in vivo response of infused allogeneic splenocytes. his(6)CTLA-4.FasL reduces the number of cells in each cell division, and increases the percentage of dead cells in each division. These findings are consistent with an antigen-induced cell death of the alloreactive cells, and bolsters recombinant TCSP promise as a therapeutic for transplantation diseases.

Presentación atípica de un adenoma pleomorfo de la glándula lagrimal con focos de necrosis / Atypical presentation of lacrimal gland pleomorphic adenoma with necrotic foci

CASO CLÍNICO: Varón de 48 años que acude por dolor en región periorbitaria superior izquierda, con sospecha de dacrioadenitis. Tras mejoría clínica y sospecha de dacriops se decide extirpar dicha lesión. La anatomía patológica diagnostica un adenoma pleomorfo de la glándula lagrimal con áreas de necrosis. DISCUSIÓN: La forma de presentación de un adenoma pleomorfo suele ser asintomática. Sin embargo, la presencia de dolor en este caso puede estar relacionada con la necrosis observada en el estudio histológico. Aunque no está descrito en glándulas lagrimales, sí que existen referencias de necrosis de adenomas pleomorfos de glándulas salivares con dolor en la presentación

CLINICAL CASE: The case is presented of 48 year-old male complaining of a painful left upper eyelid and swelling of the lacrimal gland, with a suspicion of dacryoadenitis. Removal was decided after dacriops suspicion. Histopathology diagnosed a pleomorphic adenoma of the lacrimal gland, with areas of necrosis. DISCUSSION: Lacrimal gland pleomorphic adenoma usually presents as a slowly progressive painless mass. However, painful presentation in this case might be related with necrotic foci found in the histopathological examination. Although not described in lacrimal glands, pleomorphic adenomas have already been reported in the major and minor salivary glands, and these patients also presented with a painful mass

Enhancement of HIV-specific CD8 T cell responses by dual costimulation with CD80 and CD137L.

HIV-specific CD8 T cell responses are defective in chronic HIV infection. In this study, we report that costimulation with either CD137L (4-1BBL) or CD80 (B7.1) enhanced the Ag-specific expansion and acquisition of effector function by HIV-specific memory CD8 T cells. Ag-specific T cells from recently infected donors showed maximal expansion with single costimulatory molecules. Dual costimulation of T cells from recently infected donors or from healthy donors responding to influenza epitopes led to enhanced responses when the accumulation of cytokines was measured. However, accumulation of regulatory cytokines, particularly IFN-gamma, led to inhibition of further Ag-specific CD8 T cell expansion in the cultures. This inhibition was relieved by neutralization of IFN-gamma or of IFN-gamma, TNF, and IL-10. Thus, strong costimulation of T cells in vitro can lead to induction of regulatory cytokines at levels that limit further T cell expansion. In marked contrast, T cells from long-term (>4 years) infected HIV+ donors exhibited reduced Ag-specific CD8 T cell expansion, reduced CD4 T cell responses, and minimal cytokine accumulation. Dual costimulation with both 4-1BBL and B7.1 enhanced responses of T cells from long-term infected subjects to a level similar to that obtained with T cells from early in HIV infection. Experiments with purified CD8 T cells showed that B7.1 and 4-1BBL could act directly and synergistically on CD8 T cells. Taken together, these data suggest that 4-1BBL and B7.1 have additive or synergistic effects on HIV-specific CD8 T cell responses and represent a promising combination for therapeutic vaccination for HIV.