Ernest Dodoo

Anti-PD-1/PD-L1 therapy for infectious diseases: learning from the cancer paradigm

OBJECTIVESnImmune checkpoint pathways regulate optimal host immune responses against transformed cells, induce immunological memory, and limit tissue pathology. Conversely, aberrant immune checkpoint activity signifies a poor prognosis in cancer and infectious diseases. Host-directed therapy (HDT) via immune checkpoint blockade has revolutionized cancer treatment with therapeutic implications for chronic infections, thus laying the foundation for this review.nnnMETHODSnOnline literature searches were performed via PubMed, PubMed Central, and Google using the keywords immune checkpoint inhibition; host-directed therapy; T cell exhaustion; cancer immunotherapy; anti-PD-1 therapy; anti-PD-L1 therapy; chronic infections; antigen-specific cells; tuberculosis; malaria; viral infections; human immunodeficiency virus; hepatitis B virus; hepatitis C virus; cytomegalovirus and Epstein-Barr virus. Search results were filtered based on relevance to the topics covered in this review.nnnRESULTSnThe use of monoclonal antibodies directed against the antigen-experienced T-cell marker programmed cell death 1 (PD-1) and its ligand PD-L1 in the context of chronic infectious diseases is reviewed. The potential pitfalls and precautions, based on clinical experience from treating patients with cancer with PD-1/PD-L1 pathway inhibitors, are also described.nnnCONCLUSIONSnAnti-PD-1/PD-L1 therapy holds promise as adjunctive therapy for chronic infectious diseases such as tuberculosis and HIV, and must therefore be tested in randomized clinical trials.

Expansion of Tumor-reactive T Cells From Patients With Pancreatic Cancer.

Generation of T lymphocytes with reactivity against cancer is a prerequisite for effective adoptive cellular therapies. We established a protocol for tumor-infiltrating lymphocytes (TILs) from patients with pancreatic ductal adenocarcinoma. Tumor samples from 17 pancreatic cancer specimens were cultured with cytokines (IL-2, IL-15, and IL-21) to expand TILs. After 10 days of culture, TILs were stimulated with an anti-CD3 antibody (OKT3) and irradiated allogeneic peripheral blood mononuclear cells. Reactivity of TILs against tumor-associated antigens (mesothelin, survivin, or NY-ESO-1) was detected by intracellular cytokine production by flow cytometry. Cytotoxicity was measured using a Chromium 51 release assay, and reactivity of TILs against autologous tumor cells was detected by INF-&ggr; production (ELISA). TIL composition was tested by CD45RA, CCR7, 4-1BB, LAG-3, PD-1, TIM3, and CTLA-4 marker analysis. TCR V&bgr; was determined by flow cytometry and TCR clonality was gauged measuring the CDR3 region length by PCR analysis and subsequent sequencing. We could reliably obtain TILs from 17/17 patients with a majority of CD8+ T cells. CD3+CD8+, CD3+CD4+, and CD3+CD4−CD8− [double-negative (DN) T cells] resided predominantly in central (CD45RA−CCR7+) and effector (CD45RA−CCR7−) memory subsets. CD8+ TILs tested uniformly positive for LAG-3 (about 100%), whereas CD4+ TILs showed only up to 12% LAG-3+ staining and PD-1 showed a broad expression pattern in TILs from different patients. TILs from individual patients recognized strongly (up to 11.9% and 8.2% in CD8+) NY-ESO-1, determined by ICS, or mesothelin, determined respectively by TNF-&agr; and IFN-&ggr; production. Twelve of 17 of CD8+ TILs showed preferential expansion of certain TCR V&bgr; families (eg, 99.2% V&bgr;13.2 in CD8+ TILs, 77% in the V&bgr;1, 65.9% in the V&bgr;22, and 63.3% in the V&bgr;14 family). TCR CDR3 analysis exhibited monoclonal or oligoclonal TCRs, some of them (eg, CD8+ V&bgr;13.2) reacting strongly against autologous tumor defined by INF-&ggr; production or by cytotoxicity. We have optimized methods for generating pancreatic cancer–specific TILs that can be used for adoptive cellular therapy of patients with pancreatic cancer.

B in TB: B Cells as Mediators of Clinically Relevant Immune Responses in Tuberculosis

The protective role of B cells and humoral immune responses in tuberculosis infection has been regarded as inferior to cellular immunity directed to the intracellular pathogen Mycobacterium tuberculosis. However, B-cell–mediated immune responses in tuberculosis have recently been revisited in the context of B-cell physiology and antigen presentation. We discuss in this review the diverse functions of B cells in tuberculosis, with a focus on their biological and clinical relevance to progression of active disease. We also present the peptide microarray platform as a promising strategy to discover unknown antigenic targets of M. tuberculosis that could contribute to the better understanding of epitope focus of the humoral immune system against M. tuberculosis.

T-Cell Therapy: Options for Infectious Diseases

The emergence of drug-resistant tuberculosis is challenging tuberculosis control worldwide. In the absence of an effective vaccine to prevent primary infection with Mycobacterium tuberculosis and tuberculosis disease, host-directed therapies may offer therapeutic options, particularly for patients with multidrug-resistant and extensively drug-resistant tuberculosis where prognosis is often limited. CD8+ and CD4+ T cells mediate antigen-specific adaptive cellular immune responses. Their use in precision immunotherapy in clinical conditions, especially in treating cancer as well as for prevention of life-threatening viral infections in allogeneic transplant recipients, demonstrated safety and clinical efficacy. We review key achievements in T-cell therapy, including the use of recombinant immune recognition molecules (eg, T-cell receptors and CD19 chimeric antigen receptors), and discuss its potential in the clinical management of patients with drug-resistant and refractory tuberculosis failing conventional therapy.

Mycobacterium tuberculosis proteins involved in cell wall lipid biosynthesis improve BCG vaccine efficacy in a murine TB model

OBJECTIVESnAdvances in tuberculosis (TB) vaccine development are urgently required to enhance global disease management. We evaluated the potential of Mycobacterium tuberculosis (M. tb)-derived protein antigens Rv0447c, Rv2957 and Rv2958c to boost BCG vaccine efficacy in the presence or absence of glucopyranosyl lipid adjuvant formulated in a stable emulsion (GLA-SE) adjuvant.nnnMETHODSnMice received the BCG vaccine, followed by Rv0447c, Rv2957 and Rv2958c protein boosting with or without GLA-SE adjuvant 3 and 6 weeks later. Immune responses were examined at given time points. 9 weeks post vaccination, mice were aerosol-challenged with M. tb, and sacrificed at 6 and 12 weeks to assess bacterial burden.nnnRESULTSnVaccination of mice with BCG and M. tb proteins in the presence of GLA-SE adjuvant triggered strong IFN-γ and IL-2 production by splenocytes; more TNF-α was produced without GLA-SE addition. Antibody responses to all three antigens did not differ, with or without GLA-SE adjuvant. Protein boosting without GLA-SE adjuvant resulted in vaccinated animals having better control of pulmonary M. tb load at 6 and 12 weeks post aerosol infection, while animals receiving the protein boost with GLA-SE adjuvant exhibited more bacteria in the lungs.nnnCONCLUSIONSnOur data provides evidence for developing Rv2958c, Rv2957 and Rv0447c in a heterologous prime-boost vaccination strategy with BCG.

Immune recognition surface construction of Mycobacterium tuberculosis epitope-specific antibody responses in tuberculosis patients identified by peptide microarrays

BACKGROUNDnUnderstanding of humoral immune responses in tuberculosis (TB) is gaining interest, since B-cells and antibodies may be important in diagnosis as well as protective immune responses. High-content peptide microarrays (HCPM) are highly precise and reliable for gauging specific antibody responses to pathogens, as well as autoantigens.nnnMETHODSnAn HCPM comprising epitopes spanning 154 proteins of Mycobacterium tuberculosis was used to gauge specific IgG antibody responses in sera of TB patients from Africa and South America. Open source software for general access to this method is provided.nnnRESULTSnThe IgG response pattern of TB patients differs from that of healthy individuals, with the molecular complexity of the antigens influencing the strength of recognition. South American individuals with or without TB exhibited a generally stronger serum IgG response to the tested M. tuberculosis antigens compared to their African counterparts. Individual M. tuberculosis peptide targets were defined, segregating patients with TB from Africa versus those from South America.nnnCONCLUSIONSnThese data reveal the heterogeneity of epitope-dependent humoral immune responses in TB patients, partly due to geographical setting. These findings expose a new avenue for mining clinically meaningful vaccine targets, diagnostic tools, and the development of immunotherapeutics in TB disease management or prevention.

Humoral immune profiling of mycobacterial antigen recognition in sarcoidosis and Löfgren’s syndrome using high-content peptide microarrays

INTRODUCTIONnSarcoidosis is considered an idiopathic granulomatous disease, although similar immunological and clinical features with tuberculosis (TB) suggest mycobacterial involvement in its pathogenesis. High-content peptide microarrays (HCPM) may help to decipher mycobacteria-specific antibody reactivity in sarcoidosis.nnnMETHODSnSerum samples from patients with sarcoidosis, Löfgrens syndrome, and TB, as well as from healthy individuals (12/group), were tested on HCPM containing 5964 individual peptides spanning 154 Mycobacterium tuberculosis proteins displayed as 15-amino acid stretches. Inclusion/exclusion and significance analyses were performed according to published methods.nnnRESULTSnEach study group recognized 68-78% M. tuberculosis peptides at least once. M. tuberculosis epitope recognition by sarcoidosis patient sera was 42.7%, and by TB patient sera was 39.1%. Seven and 16 peptides were recognized in 9/12 (75%) and 8/12 (67%) sarcoidosis patient sera but not in TB patient sera, respectively. Nine (75%) and eight (67%) out of twelve TB patient sera, respectively recognized M. tuberculosis peptides that were not recognized in sarcoidosis patient sera.nnnCONCLUSIONSnSpecific IgG recognition patterns for M. tuberculosis antigens in sarcoidosis patients re-affirm mycobacterial involvement in sarcoidosis, providing biologically relevant targets for future studies pertaining to diagnostics and immunotherapy.

Mesothelin-specific Immune Responses Predict Survival of Patients With Brain Metastasis

Background Patients with advanced malignancies, e.g. lung cancer, ovarian cancer or melanoma, frequently present with brain metastases. Clinical presentation and disease progression of cancer is in part shaped by the interaction of the immune system with malignant cells. Antigen-targeted immune responses have been implicated in the prolonged survival of patients with cancer. This includes the tumor-associated antigen (TAA) mature mesothelin, a 40 kDa cell surface-bound antigen that is overexpressed in several malignancies including lung ovarian and pancreatic cancer. We examined in an observational, prospective study the survival of patients with brain metastases in association with clinical parameters and cellular immune responses to molecularly defined TAAs or viral (control) target antigens. Methods Immune cells in peripheral blood obtained from thirty-six patients with brain metastases were tested for cytokine production in response to a broad panel of defined viral and TAA target antigens, including full-length mesothelin. Incubation of immune cells with antigenic targets was carried out in i) medium alone, (ii) in a cytokine cocktail of interleukin (IL)-2/IL-15/IL-21, or (iii) IL-2/IL-7. Supernatants were tested for interferon gamma (IFN-γ) production, after which univariate and multivariate analyses (Cox stepwise regression model) were performed to identify independent clinical and immunological factors associated with patient survival. Patients were followed-up for at least 500 days after surgery or until death. Findings Univariate analysis identified age, gender, radiotherapy and mutational load as clinical parameters affecting survival of patients with brain metastases. Cox multivariate analysis showed that radiotherapy (P = 0·004), age (P = 0·029) and IFN-γ responses to mature mesothelin, conditioned by IL-2/IL-7 (P = 0·045) were independent predictors of the survival of patients from surgery up to follow-up or death. Interpretation This is the first evidence that immune responses to mesothelin serve as a marker of increased overall survival in patients with brain metastases, regardless of the primary tumor origin. Analyses of immunological markers could potentially serve as prognostic markers in patients with brain metastases and help to select patients in need for adjunct, immunological, treatment strategies.

The impact of inflationary cytomegalovirus-specific memory T cells on anti-tumour immune responses in patients with cancer

Human cytomegalovirus (CMV) is a ubiquitous, persistent beta herpesvirus. CMV infection contributes to the accumulation of functional antigen‐specific CD8+ T‐cell pools with an effector‐memory phenotype and enrichment of these immune cells in peripheral organs. We review here this ‘memory T‐cell inflation’ phenomenon and associated factors including age and sex. ‘Collateral damage’ due to CMV‐directed immune reactivity may occur in later stages of life – arising from CMV‐specific immune responses that were beneficial in earlier life. CMV may be considered an age‐dependent immunomodulator and a double‐edged sword in editing anti‐tumour immune responses. Emerging evidence suggests that CMV is highly prevalent in patients with a variety of cancers, particularly glioblastoma. A better understanding of CMV‐associated immune responses and its implications for immune senescence, especially in patients with cancer, may aid in the design of more clinically relevant and tailored, personalized treatment regimens. ‘Memory T‐cell inflation’ could be applied in vaccine development strategies to enrich for immune reactivity where long‐term immunological memory is needed, e.g. in long‐term immune memory formation directed against transformed cells.

Multidisciplinary management of clival chordomas; long-term clinical outcome in a single-institution consecutive series

ObjectiveChordomas of the skull base have high recurrence rates even after radical resection and adjuvant radiotherapy. We evaluate the long-term clinical outcome using multidisciplinary management in the treatment of clival chordomas.MethodsBetween 1984 and 2015, 22 patients diagnosed with an intracranial chordoma were treated at the Karolinska University Hospital, Stockholm, Sweden. Sixteen of 22 were treated with Gamma Knife radiosurgery (GKRS) for tumour residual or progression during the disease course. Seven of 22 received adjuvant fractionated radiotherapy and 5 of these also received proton beam radiotherapy.ResultsFifteen of 22 (68%) patients were alive at follow-up after a median of 80xa0months (range 22–370xa0months) from the time of diagnosis. Six were considered disease free after >10-year follow-up. The median tumour volume at the time of GKRS was 4.7xa0cm3, range 0.8–24.3xa0cm3. Median prescription dose was 16 Gy, range 12–20 Gy to the 40–50% isodose curve. Five patients received a second treatment with GKRS while one received three treatments. After GKRS patients were followed with serial imaging for a median of 34xa0months (range 6–180xa0months). Four of 16 patients treated with GKRS were in need of a salvage microsurgical procedure compared to 5/7 treated with conventional or proton therapy.ConclusionAfter surgery, 7/22 patients received conventional and/or photon therapy, while 15/22 were treated with GKRS for tumour residual or followed with serial imaging with GKRS as needed upon tumour progression. With this multidisciplinary management, 5- and 10-year survivals of 82% and 50% were achieved, respectively.