RESUMO
Perifosine treatment exhibits a complex molecular response including the inhibition of Akt or the induction of apoptosis via clustering of death receptors in lipid rafts. However, the molecular response can vary between different tumor entities and the contribution of each target pathway to the activity of Perifosine might be distinct depending on the tumor entity or the agent combined with Perifosine. In this review we discuss the current view on the mechanism of action of perifosine in cancer and the contribution of the molecular targets of Perifosine to its activity.
Assuntos
Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Fosforilcolina/análogos & derivados , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Microdomínios da Membrana/efeitos dos fármacos , Microdomínios da Membrana/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Fosforilcolina/química , Fosforilcolina/metabolismo , Fosforilcolina/farmacologia , Fosforilcolina/uso terapêutico , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Morte Celular/metabolismo , Transdução de SinaisRESUMO
BACKGROUND: Specific cell targeting is an important, yet unsolved problem in bacteria-based therapeutic applications, like tumor or gene therapy. Here, we describe the construction of a novel, internalin A and B (InlAB)-deficient Listeria monocytogenes strain (Lm-spa+), which expresses protein A of Staphylococcus aureus (SPA) and anchors SPA in the correct orientation on the bacterial cell surface. RESULTS: This listerial strain efficiently binds antibodies allowing specific interaction of the bacterium with the target recognized by the antibody. Binding of Trastuzumab (Herceptin®) or Cetuximab (Erbitux®) to Lm-spa+, two clinically approved monoclonal antibodies directed against HER2/neu and EGFR/HER1, respectively, triggers InlAB-independent internalization into non-phagocytic cancer cell lines overexpressing the respective receptors. Internalization, subsequent escape into the host cell cytosol and intracellular replication of these bacteria are as efficient as of the corresponding InlAB-positive, SPA-negative parental strain. This specific antibody/receptor-mediated internalization of Lm-spa+ is shown in the murine 4T1 tumor cell line, the isogenic 4T1-HER2 cell line as well as the human cancer cell lines SK-BR-3 and SK-OV-3. Importantly, this targeting approach is applicable in a xenograft mouse tumor model after crosslinking the antibody to SPA on the listerial cell surface. CONCLUSIONS: Binding of receptor-specific antibodies to SPA-expressing L. monocytogenes may represent a promising approach to target L. monocytogenes to host cells expressing specific receptors triggering internalization.
Assuntos
Anticorpos Antibacterianos/metabolismo , Proteínas de Bactérias/genética , Endocitose , Listeria monocytogenes/patogenicidade , Proteínas de Membrana/deficiência , Proteína Estafilocócica A/metabolismo , Animais , Linhagem Celular Tumoral , Receptores ErbB/imunologia , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Ligação Proteica , Receptor ErbB-2/imunologia , Proteína Estafilocócica A/genéticaRESUMO
A tumor promoting role of macrophages has been described for a transgenic murine breast cancer model. In this model tumor-associated macrophages (TAMs) represent a major component of the leukocytic infiltrate and are associated with tumor progression. Shigella flexneri is a bacterial pathogen known to specificly induce apotosis in macrophages. To evaluate whether Shigella-induced removal of macrophages may be sufficient for achieving tumor regression we have developed an attenuated strain of S. flexneri (M90TDeltaaroA) and infected tumor bearing mice. Two mouse models were employed, xenotransplantation of a murine breast cancer cell line and spontanous breast cancer development in MMTV-HER2 transgenic mice. Quantitative analysis of bacterial tumor targeting demonstrated that attenuated, invasive Shigella flexneri primarily infected TAMs after systemic administration. A single i.v. injection of invasive M90TDeltaaroA resulted in caspase-1 dependent apoptosis of TAMs followed by a 74% reduction in tumors of transgenic MMTV-HER-2 mice 7 days post infection. TAM depletion was sustained and associated with complete tumor regression.These data support TAMs as useful targets for antitumor therapy and highlight attenuated bacterial pathogens as potential tools.
Assuntos
Macrófagos/metabolismo , Neoplasias Mamárias Animais/metabolismo , Shigella/metabolismo , Animais , Apoptose , Linhagem Celular Tumoral , Separação Celular , Progressão da Doença , Feminino , Células HeLa , Humanos , Camundongos , Camundongos Transgênicos , Mutação , Invasividade Neoplásica , Transplante de NeoplasiasRESUMO
BACKGROUND: Intravesical immunotherapy with Mycobacterium bovis (M. bovis) bacillus Calmette-Guerin (BCG) is the current standard of care against superficial, high-grade transitional cell carcinoma (TCC) of the urinary bladder (carcinoma in situ and pathologic T1, grade 3 disease). However, individual patient outcome is barely predictable because of the lack of serum markers. Consequently, progression to muscle-invasive bladder cancer and critical delay of treatments (such as neoadjuvant combination chemotherapy and/or radical cystectomy) often occur. The objectives of this study were to identify a marker for measuring the BCG-induced immune response and to predict the outcomes and potential improvements of BCG immunotherapy. METHODS: Because host immunoresponse mediates BCG activity, the authors screened a combinatorial random peptide library on the circulating pool of immunoglobulins (Igs) purified from an index patient after successful BCG immunotherapy to identify the corresponding target antigen(s). RESULTS: An immunogenic peptide motif was selected, isolated, and validated from M. bovis BCG heat-shock protein 65 (HSP-65) as a dominant epitope of the humoral response to treatment. Increasing IgA and IgG anti-HSP-65 titers specifically predicted a positive patient outcome in a cohort of patients with bladder cancer relative to several cohorts of control patients. CONCLUSIONS: The current results indicated that antibody production against M. bovis BCG HSP-65 can serve as a serologic marker for the predictive outcome of BCG immunotherapy. Subsequent studies will determine the value of this candidate marker to modify BCG-based treatment for individual patients with bladder cancer.
Assuntos
Anticorpos Antibacterianos/biossíntese , Vacina BCG/uso terapêutico , Carcinoma de Células de Transição/terapia , Proteínas de Choque Térmico/imunologia , Neoplasias da Bexiga Urinária/terapia , Idoso , Idoso de 80 Anos ou mais , Vacina BCG/imunologia , Biomarcadores/análise , Carcinoma de Células de Transição/imunologia , Proteínas de Choque Térmico/análise , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium bovis/metabolismo , Resultado do Tratamento , Neoplasias da Bexiga Urinária/imunologiaRESUMO
The attenuated Salmonella enterica serovar Typhi strain Ty21a (Ty21a) is the only attenuated live oral vaccine against typhoid fever. Ty21a is also an attractive carrier for the delivery of heterologous antigens. We have used Ty21a for antigen delivery via the hemolysin (HlyA) secretion system of Escherichia coli, the prototype of the type I secretion system (T1SS). In this study, we identified by genetic complementation that the specific mutation of rpoS correlated with the hemolysin production of strain Ty21a. We furthermore showed that complementation with a plasmid encoding rfaH, which is described to be a downstream target of rpoS, led to increased expression and secretion of hemolysin. Finally, we demonstrated a significant enhancement of antibody responses against the heterologous HlyA antigen of Ty21a after immunization of mice with rfaH complemented S. typhi strain secreting HlyA compared with the same strain without rfaH plasmid.
Assuntos
Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Salmonella typhi/genética , Salmonella typhi/imunologia , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/fisiologia , Teste de Complementação Genética , Proteínas Hemolisinas/biossíntese , Camundongos , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/metabolismo , Plasmídeos , Fator sigma/genética , Fator sigma/fisiologia , Transativadores/genética , Transativadores/metabolismo , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologiaRESUMO
The attenuated Salmonella typhi strain Ty21a is the main constituent of Vivotif, the only attenuated live oral vaccine against typhoid fever. In comparison with antibiotics, the 'magic bullets' which Paul Ehrlich was striving for to treat infectious diseases, this vaccine should be viewed as a 'magic shield', because rather than treating typhoid fever after the infection has started, immunisation with this vaccine strain prevents infection and disease by the induction of specific immune responses. Ty21a is also an attractive carrier for the delivery of heterologous antigens. Recently, we successfully used Ty21a for antigen delivery via the haemolysin secretion system of Escherichia coli, which allows efficient protein secretion from the carrier bacteria.
Assuntos
Antígenos Heterófilos/imunologia , Polissacarídeos Bacterianos , Febre Tifoide/prevenção & controle , Vacinas Tíficas-Paratíficas , Vacinas Atenuadas , Animais , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/imunologia , Vetores Genéticos , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/imunologia , Humanos , Salmonella typhi/genética , Salmonella typhi/imunologiaRESUMO
Many cellular signaling pathways are involved in the development of cancer. Depending on the tumor entity, the nature as well as the mode of activation can differ. Some signaling pathways frequently show changes as all tumor cells have to fulfill some basic requirements such as independence from growth factors or insensitivity against apoptosis. In this review, the possibilities of a tumor to manipulate signaling pathways to reach these goals are exemplified based on an archetypical melanoma cell. In addition, new therapeutic options based on the knowledge of signaling pathways will be discussed.
Assuntos
Biomarcadores Tumorais/metabolismo , Melanoma/metabolismo , Proteínas de Neoplasias/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/metabolismo , Animais , Regulação Neoplásica da Expressão Gênica , Humanos , Melanoma/terapia , Modelos Biológicos , Neoplasias Cutâneas/terapiaRESUMO
BACKGROUND: Differences in HLA allele frequencies between the diseased and healthy populations may signify efficient immune responses, a notion that has been successfully tested for infectious diseases or for association with genetic elements involved in a distinct type of immunity. This retrospective study is intended to detect differences in MHC class I carrier frequencies of advanced melanoma patients compared to healthy bone marrow donors. METHODS: The HLA-A and -B carrier frequencies of 748 stage IV melanoma patients retrieved from serotyping at 6 different centers in Germany were compared using a chi-square test to 13,386 fully HLA typed bone marrow donors registered in the German national bone marrow donor registry. RESULTS: The comparison of HLA carrier frequencies in advanced cancer patients with healthy bone marrow donors revealed a significant decrease in HLA-B8 carrier frequencies, which was also apparent in patients with advanced disease compared to patients with loco-regional disease. CONCLUSION: The data suggest that protective immune responses restricted to distinct MHC class I molecules may be operational in a subset of melanoma patients, which is the prerequisite for a large scale screen for the corresponding epitopes. Alternatively, the known association of the ancestral haplotype HLA-A1, -B8 and -DR3 with genetic elements such as distinct TNF-alpha alleles might have a protective effect on disease progression. In any case, identification of the cause of protection within this patient subset might lead to a significant improvement in the efficacy of current immunotherapeutic approaches.
Assuntos
Antígeno HLA-B8/imunologia , Melanoma/imunologia , Melanoma/patologia , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Frequência do Gene , Genes MHC Classe I , Antígenos HLA-A , Antígenos HLA-B , Antígeno HLA-B8/genética , Teste de Histocompatibilidade , Humanos , Imunoterapia , Melanoma/genética , Estadiamento de Neoplasias , Fenótipo , Estudos Retrospectivos , Neoplasias Cutâneas/genéticaRESUMO
BACKGROUND: Serine-threonine kinases of the Raf family (A-Raf, B-Raf, C-Raf) are central players in cellular signal transduction, and thus often causally involved in the development of cancer when mutated or over-expressed. Therefore these proteins are potential targets for immunotherapy and a possible basis for vaccine development against tumors. In this study we analyzed the functionality of a new live C-Raf vaccine based on an attenuated Salmonella enterica serovar Typhimurium aroA strain in two Raf dependent lung tumor mouse models. METHODS: The antigen C-Raf has been fused to the C-terminal secretion signal of Escherichia coli alpha-hemolysin and expressed in secreted form by an attenuated aroA Salmonella enterica serovar Typhimurium strain via the alpha-hemolysin secretion pathway. The effect of the immunization with this recombinant C-Raf strain on wild-type C57BL/6 or lung tumor bearing transgenic BxB mice was analyzed using western blot and FACS analysis as well as specific tumor growth assays. RESULTS: C-Raf antigen was successfully expressed in secreted form by an attenuated Salmonella enterica serovar Typhimurium aroA strain using the E. coli hemolysin secretion system. Immunization of wild-type C57BL/6 or tumor bearing mice provoked specific C-Raf antibody and T-cell responses. Most importantly, the vaccine strain significantly reduced tumor growth in two transgenic mouse models of Raf oncogene-induced lung adenomas. CONCLUSIONS: The combination of the C-Raf antigen, hemolysin secretion system and Salmonella enterica serovar Typhimurium could form the basis for a new generation of live bacterial vaccines for the treatment of Raf dependent human malignancies.
Assuntos
Adenoma/prevenção & controle , Vacinas Anticâncer/imunologia , Proteínas de Escherichia coli/imunologia , Proteínas Hemolisinas/imunologia , Neoplasias Pulmonares/prevenção & controle , Proteínas Proto-Oncogênicas c-raf/imunologia , Salmonella typhimurium/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Vacinas Anticâncer/uso terapêutico , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Imunidade Celular , Imunização/métodos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Plasmídeos/genética , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/uso terapêutico , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Vacinas Atenuadas/imunologia , Vacinas Atenuadas/uso terapêuticoRESUMO
This study examined the suitability of the hemolysin secretion system of Escherichia coli for expression and delivery of alpha-hemolysin (HlyA) by the S. typhi Ty21a strain, the only live oral Salmonella vaccine strain licensed for human use, under in vitro and in vivo conditions. For this purpose, two plasmid vectors encoding either the whole alpha-hemolysin of E. coli (pANN202-812/pMOhly2) or the hemolysin secretion signal (pMOhly1) were transferred into S. typhi Ty21a. S. typhi Ty21a carrying pANN202-812/pMOhly2 revealed efficient secretion of hemolysin in vitro. After formulation according to a process suitable for commercial production of Salmonella-based live bacterial vaccines, plasmids were shown to be stable in Ty21a and hemolysin secretion was demonstrated even after storage of the strains under real-time and stress conditions. After intranasal immunization of mice with S. typhi Ty21a/pANN202-812 plasmids are stable in vivo, and immunization induced a profound immune response against the heterologous HlyA antigen. Therefore, the combination of the hemolysin secretion system and S. typhi Ty21a could form the basis for a new generation of live bacterial vaccines.
Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/metabolismo , Proteínas de Escherichia coli/imunologia , Proteínas de Escherichia coli/metabolismo , Proteínas Hemolisinas/imunologia , Vacinas contra Salmonella/administração & dosagem , Salmonella typhi/metabolismo , Animais , Antígenos de Bactérias/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Vetores Genéticos , Proteínas Hemolisinas/genética , Imunização , Camundongos , Camundongos Endogâmicos C57BL , Plasmídeos , Vacinas contra Salmonella/genética , Salmonella typhi/genéticaRESUMO
BACKGROUND: Mutations of the BRAF gene are the most common genetic alteration in melanoma. Moreover, BRAF mutations are already present in benign nevi. Being overexpressed and mutated, B-Raf is a potential target for the immune system and as this mutation seems to be an early event, a humoral immune response against this antigen might serve as a diagnostic tool for detection of high risk patients. METHODS: 372 sera of 148 stage IV melanoma patients and 119 sera of non-melanoma patients were screened for B-Raf, B-Raf V599E and C-Raf specific antibodies by an ELISA assay. Sera were screened for specific total Ig and for IgG. Serum titers were compared with a two tailed Mann-Whitney U test. Sera with titers of 1:300 or higher were termed positive and groups were compared with a two tailed Fisher's exact test. RESULTS: B-Raf specific antibodies recognizing both B-Raf and B-Raf V599E were detected in 8.9% of the sera of melanoma patients and in 2,5% of the control group. Raf specific IgG was detected in some patients at very low levels. B-Raf specific antibody responses did not correlate with clinical parameters but in some cases, B-Raf antibodies emerged during disease progression. CONCLUSION: These findings imply that B-Raf is immunogenic in melanoma patients and that it might serve as a potential target for immunotherapy. However, B-Raf specific antibodies emerge at rather late stages of melanoma progression and are present only with a low frequency indicating that spontaneous B-Raf specific antibodies are not an early marker for melanoma, but rather may serve as a therapeutic target.
Assuntos
Anticorpos Antineoplásicos/sangue , Melanoma/imunologia , Proteínas Proto-Oncogênicas B-raf/imunologia , Neoplasias Cutâneas/imunologia , Anticorpos Antineoplásicos/imunologia , Especificidade de Anticorpos , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/sangue , Neoplasias Cutâneas/sangueRESUMO
Activating BRAF somatic missense mutations within the kinase domain are present in 60-66% of melanomas. The vast majority of these represent a single substitution of glutamate for valine (V599E). Here, we demonstrate spontaneous HLA-B*2705-restricted cytotoxic T-cell responses against an epitope derived from (V599E)BRaf. These T-cell responses were mutation specific as the corresponding epitope derived from wild-type BRaf was not recognized. The loss of the (V599E)BRAF genotype during progression from primary to metastatic melanoma in patients with (V599E)BRaf specific T-cell responses suggests an active immune selection of nonmutated melanoma clones by the tumor-bearing host.
Assuntos
Epitopos/imunologia , Antígenos HLA-B/imunologia , Melanoma/genética , Melanoma/imunologia , Fragmentos de Peptídeos/imunologia , Proteínas Proto-Oncogênicas c-raf/genética , Progressão da Doença , Epitopos/genética , Epitopos/metabolismo , Genótipo , Antígenos HLA-B/metabolismo , Antígeno HLA-B27 , Humanos , Melanoma/secundário , Mutação de Sentido Incorreto , Fragmentos de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas B-raf , Proteínas Proto-Oncogênicas c-raf/imunologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/metabolismo , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/metabolismoRESUMO
Immunization with plasmid DNA vectors represents a promising new approach to vaccination. It has been shown to elicit humoral and cellular immunity and protection in various infection models. Here, we assessed the immunogenicity and protective efficacy of a DNA vaccine vector encoding the antigen 85A (Ag85A) of Mycobacterium tuberculosis. Since intramuscular (i.m.) immunization with naked DNA requires considerable amounts of DNA in order to be effective, we evaluated a strategy to reduce the amount of DNA needed. To this end, we used Ag85A DNA adsorbed onto cationic poly(DL-lactide-co-glycolide) (PLG) microparticles and observed similar levels of protection against aerosol challenge in mice using doses of PLG-DNA two orders of magnitude lower than with naked DNA itself.
Assuntos
Vacinas contra a Tuberculose/administração & dosagem , Vacinas contra a Tuberculose/uso terapêutico , Tuberculose/prevenção & controle , Adsorção , Animais , Primers do DNA , Sistemas de Liberação de Medicamentos , Injeções Intramusculares , Interferon gama/metabolismo , Ácido Láctico , Camundongos , Camundongos Endogâmicos BALB C , Microesferas , Mycobacterium bovis/genética , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/imunologia , Ácido Poliglicólico , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Polímeros , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Baço/citologia , Baço/metabolismo , Baço/microbiologia , Linfócitos T/metabolismo , Tuberculose/imunologia , Tuberculose/microbiologia , Vacinas contra a Tuberculose/química , Vacinas de DNA/administração & dosagem , Vacinas de DNA/química , Vacinas de DNA/uso terapêuticoAssuntos
Neoplasias Pulmonares/enzimologia , Proteínas Proto-Oncogênicas c-raf/fisiologia , Animais , Antígenos de Neoplasias/química , Humanos , Imunoterapia/métodos , Modelos Biológicos , Modelos Moleculares , Mutação , Fenótipo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteína Supressora de Tumor p53/genéticaRESUMO
CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica , Receptores de Interleucina-2/imunologia , Transferência Adotiva , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Vacinas Bacterianas/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/transplante , Linfócitos T CD8-Positivos/metabolismo , Imunização Secundária , Listeria monocytogenes/imunologia , Listeriose/imunologia , Ativação Linfocitária , Depleção Linfocítica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Peptídeos/imunologia , Baço/citologia , Baço/imunologia , Vacinação , Vacinas de DNA/imunologiaRESUMO
Live recombinant vaccines expressing defined pathogen-derived Ags represent powerful candidates for future vaccination strategies. In this study, we report on the differential induction of protective cell-mediated immunity elicited by different recombinant Mycobacterium bovis Bacille Calmette-Guérin (BCG) strains displaying p60 Ag of Listeria monocytogenes in secreted, cytosolic, or membrane-attached form for T cell recognition. Anti-listerial protection evoked by the membrane-linked p60 lipoprotein of rBCG Mp60 and that of the p60 derivative secreted by rBCG Sp60-40 were nearly equal, whereas cytosolic p60 displayed by rBCG Np60 failed to protect mice from listeriosis. In vivo depletion of CD4 or CD8 T cell subpopulations in rBCG Mp60-vaccinated mice before listerial challenge revealed interactions of both T cell subsets in anti-listerial protection. In rBCG Sp60-40-vaccinated animals, CD4 T cells predominantly contributed to anti-listerial control as shown by the failure of anti-CD8 mAb treatment to impair the outcome of listeriosis in rBCG Sp60-40-vaccinated mice after L. monocytogenes challenge. Hence, differential Ag display by rBCG influences cell-mediated immunity, which in turn may impact vaccine efficacy due to the different requirements of CD4 or CD8 T cells for pathogen elimination.